Week of December 15, 2014

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, December 15.  All times are given as local St. Louis time (Central Standard Time).  For definitions of terminology used in the night sky update, click the highlighted text.

Information updated weekly or as needed.

Join us for our next star party, Friday, January 2, 2015 held in association with the St. Louis Astronomical Society. For details, see the information at the bottom of this page.

The Sun and the Moon

Sunrise is at 7:12 a.m. on Monday, December 15 and sunset is at 4:41 p.m. providing us with about 9 hours and 30 minutes of daylight.  Even after sunset, the light from the Sun will still dimly illuminate our sky for about 1.5 hours.  This period of time is called twilight, which ends around 6:16 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 11:56 a.m. this week.

December 21 is the winter solstice.  This is the first day of winter in the northern hemisphere and the longest night of the year.  Cultures around the world observed this day for various cultural and scientific reasons.  Numerous ancient observatories were constructed some of which still stand today.  At sites such as Stonehenge, Newgrange, Chaco Canyon and Cahokia Mounds people still gather today to celebrate the winter solstice.  Ancient astronomy is fascinating and learning about such practices can enrich our own interests in observational astronomy.  Any of the sites listed above would be a good place to start learning about ancient astronomy.

Day

Sunrise

Sunset

15 Dec

7:12 a.m.

4:41 p.m.

16 Dec

7:12 a.m.

4:41 p.m.

17 Dec

7:13 a.m.

4:41 p.m.

18 Dec

7:13 a.m.

4:42 p.m.

19 Dec

7:14 a.m.

4:42 p.m.

20 Dec

7:15 a.m.

4:43 p.m.

21 Dec

7:15 a.m.

4:43 p.m.

22 Dec

7:16 a.m.

4:44 p.m.

Moonrise for Monday, December 15 occurs at 12:34 a.m. and moonset will occur at 12:34 p.m.  On Monday, December 8 the Moon will be exhibiting a waning crescent phase with about 39% of the lunar disk illuminated.  New moon occurs on December 21 at 7:37 p.m.

International Space Station (ISS) Observing

Visible passes of ISS from St. Louis this week occur during the evening hours.  The best of these is on the evening of December 22.  Learn more about this pass and others this week in the table below.

Catch ISS flying over St. Louis in the evening hours starting Monday, December 15. 

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

20 Dec

-0.8

17:46:03

10

N

17:46:15

10

N

17:46:27

10

NNE

21 Dec

-0.8

18:30:20

10

NNW

18:30:59

13

NNW

18:30:59

13

NNW

22 Dec

-1.3

17:39:55

10

NNW

17:41:47

14

NNE

17:42:31

13

NE

Magnitude (Mag): The Measure of brightness for a celestial object.  The lower the value is, the brighter the object will be.

Altitude (Alt):  The angle of a celestial object measured upwards from the observer’s horizon.

Azimuth (Az):  The direction of a celestial object, measured clockwise from an observer’s location with north being 0°, east being 90°, south being 180° and west being 270°.

For information about ISS flyovers and other visible satellites, visit www.heavens-above.com

Detailed information regarding all unmanned exploration of our universe, missions past, present, and planned, can be found at Jet Propulsion Laboratories:

http://www.jpl.nasa.gov/

The Planets Visible Without A Telescope

Mars

Mars is now in the constellation Capricornus and rises before the Sun sets.  Mars will be seen in the southwestern skies about 20 minutes after sunset.  Mars will set by 8:02 p.m. 

Jupiter

The largest planet in the solar system has returned to our evening skies.  Jupiter can be found rising by 9:13 p.m. and will be easily visible by 10:00 p.m. in the eastern sky.  Jupiter can currently be found in the constellation Leo the Lion.    

Uranus and Neptune Opposition 2014

The two most distant planets in our solar system will be at their best for the next couple of months.  Neptune has already reached opposition and Uranus will reach opposition on October 7, 2014.  The opposition of a planet is when it is in opposition with the Sun.  What that means is a planet or other body such as an asteroid is seen on the opposite side of the Earth than the Sun is.  From our perspective this is when an object is at its brightest and also coincides with the object’s closest approach to the Earth.  Only objects further from the Sun than we are can be in opposition. 

Of the two planets Uranus will be the brightest.  Uranus is already appearing as a 5.8 magnitude object and will continue to brighten until October 7.  Uranus is normally a planet that requires binoculars to be seen but when the planet is nearing opposition dark sky observers can see it with the unaided eye.  Through telescopes observers will resolve Uranus into a small disk shaped object that may display a slight greenish blue color.  Large telescopes using high magnifications up to 300x might be able to discern dark and light patches called albedo features.  These features require large aperture telescopes and better than average viewing conditions to be seen. 

Uranus is currently in the constellation Pisces.  Pisces is very difficult to see in light polluted skies so it is better to start with the Great Square of Autumn.  This asterism connects the constellations Andromeda and Pegasus all of which will be seen high in the eastern sky by 10:00 p.m.  As the Great Square sits high in the east if you follow a line connecting the stars Scheat (Beta Peg) through Algenib (Gamma Peg) about the same distance that lays between the two stars you will find three stars the stand next to one another in a straight line.  The brightest of these stars is Delta Piscium.  Uranus is about four degrees south of these stars.  You will need either a desktop planetarium program or detailed star chart to help you pinpoint which star like object is Uranus. 

http://www.iau.org/static/public/constellations/gif/PSC.gif

http://www.iau.org/static/public/constellations/gif/PEG.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Neptune reached opposition on August 29, 2014.  It is now at its peak brightness of 7.8 magnitude.  This means that you will need at least binoculars to see this distant planet even when it is at its brightest.  Through binoculars Neptune will appear as a dim star like object in the constellation Aquarius.  To find Neptune first locate the bright star Fomalhaut.  About 6 to 10 degrees north of Fomalhaut you will find six bright stars that are shaped like a hyperboloid.  Scanning the sky further north you will find the star Sigma Aquarii.  Neptune will be just east of this star.      

Using a telescope most will see a star like object that when magnified enough will reveal a greyish blue disk.  Using a large telescope and high magnification up to 300x it may be possible to detect albedo features and Neptune largest moon Triton.  Triton will appear as a dim star right next to Neptune.

Like Uranus Neptune will require some kind of astronomy software of a detailed map to find.  As we pass by these planets in our orbit see if you can detect there shift amongst the background stars.  Below are a few links that will be helpful in locating Neptune and the stars mentioned above.

http://www.iau.org/static/public/constellations/gif/AQR.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Constellation of the Month

Each month we will highlight one constellation and some of the objects that can be found within the boundaries of that constellation.  At the start of the month we will list only a few of these objects and each week we will add another to the list.  Some objects will be visible to the unaided eye and some may require a telescope.  Many of the objects listed will require a map of the sky to find or may require repeat observations to notice various properties.  Links to star charts and other information that will be useful in identifying the objects listed will be given at the end of each week’s section. 

This month we will explore the constellation Puppis the Poop Deck.  Puppis was originally part of a much larger constellation called Argo Navis.  This was the famous ship that Jason and the Argonauts sailed on during their expeditions.  In 1752 French astronomer Nicolas Louis de Lacaille broke Argo Navis into three separate constellations named Carina, Vela and Puppis.  Puppis is in the southern celestial hemisphere meaning that it is only visible later in the year when the ecliptic climbs higher in the sky.  Puppis contains a number open star clusters that we will explore for the extent December.

To find Puppis first locate Orion the Hunter.  Orion begins to rise by about 7:00 p.m. but to find Puppis you will want to wait until midnight or later.  Once you can find Orion use his famous belt and follow its bright stars down to the brightest star in the night sky, Sirius.  Once you can find Sirius look about 10 degrees to the east and you have found Puppis.  Puppis extends from as far north as Sirius all the way to the southern horizon.  The brightest stars in Puppis we can see are Pi, Rho and Zeta Puppis.  Pi and Zeta Puppis will difficult for us to see until about 2:30 a.m. when the bright stars are only 10 degrees above the horizon.

http://www.iau.org/static/public/constellations/gif/PUP.gif

http://www.iau.org/static/public/constellations/gif/ORI.gif

http://www.iau.org/static/public/constellations/gif/CMA.gif

The first star cluster in Puppis we will explore is Messier 47.  M47 is not the most beautiful of star clusters but it is one that can be seen with the naked eye.  From a dark location M47 can be seen as a dim nebulosity with the unaided eye.  It is also interesting as it was one of the missing Messier objects.  Charles Messier made calculation errors that placed M47 in the wrong part of the sky.  Before his mistake was corrected Caroline Herschel had observed and cataloged the object as NGC 2422. 

Messier is a loose grouping of about 50 stars that lie at a distance of 1,600 light years in the Orion spur of the Milky Way.  The component stars are estimated to be about 78 million years old of which two appear to be orange giant stars that are likely nearing the end of their stellar lives.  This cluster will be best viewed through binoculars as M47 covers an area of sky similar to the size of the full moon. 

Viewing M47 through a telescope will give it a similar appearance to other large clusters such as the Pleiades or the Beehive Cluster.  Through a telescope you can also look for the fine double star Sigma 1121 which has two stars at magnitudes of 7.9 and are separated by roughly 7.4 arc seconds. 

To find M47 all you have to do is find the bright star Sirius.  From this star scan about 15 degrees to the east and you will find M47.  It may take a few attempts to zero in on the cluster but this same step will also bring us to next week’s star cluster M46.

http://www.iau.org/static/public/constellations/gif/PUP.gif

The object for the week of December 8 is the star cluster Messier 46 (M46).  This open cluster has a Trumpler classification of II, 2, r meaning it is a detached from background stars, it stars have a moderate range in brightness and it is a relatively dense cluster.  M46 is estimated to have about 500 stars that are about 300 million years old and lie about 5.4 light years away.  This open cluster will be much easier to see than last week’s cluster due to its higher star density.

For those with a telescope there is an added challenge with M46.  In the same line of sight there is a planetary nebula called NGC 2438.  Planetary nebulae are the remnants of Sun-like stars that have evolved into a white dwarf shedding its outer atmosphere.  NGC 2438 is only about 2,900 light years away so it is not part of M46 but it is an added bonus once you have found M46.  It is only 10.8 magnitude so it will require dark skies and a telescope to see.  Follow the link below to learn more about this nebula. 

http://messier.seds.org/xtra/ngc/n2438.html

To find M46 use the same directions used last week to find M47.  First locate the bright star Sirius. From this star scan about 15 degrees to the east and you will find M47.  Another two degrees east and you will find M46.  For those using binoculars both M46 and M47 will fit in the same field of view.

http://www.iau.org/static/public/constellations/gif/PUP.gif  

The object for the week of December 15 is the open star cluster Messier 93 (M93).  This is a bright open cluster that lies about 3,600 light years away with stars that are estimated to be about 100 million years old.  The stars in this cluster shine with an apparent magnitude of 6.0.  This makes M93 an easy target in both binoculars and telescopes.  It has a Trumpler classification of I, 3, r meaning it is well detached from background stars, it has a wide range of stellar brightness and it is a rich star cluster with over 100 stars.  Most of the stars that can be individually resolved are bright blue giant stars but there are a few highly evolved red giants that can be seen.

To find M93 locate the bright stars Omicron 1 and Omicron 2 in Canis Major.  These two stars are about 10 degrees below Sirius.  From Omicron 1 and 2 scan another 10 degrees to the east and you will find M93.  As a useful reference to ensure you have identified M93 you can find the bright star Xi Puppis about two degrees to the south. 

Next week we will continue with the open clusters of Puppis but we will continue to move closer to the southern horizon.  For help with this week’s star cluster use the links below.

https://www.iau.org/static/public/constellations/gif/PUP.gif

https://www.iau.org/static/public/constellations/gif/CMA.gif

Our next Star Party will be held on Friday, January 2, 2014, from dusk until 10 p.m.

Weather permitting, the St. Louis Astronomical Society and the Science Center will set up a number of telescopes outdoors and be on-hand to answer your questions.  Telescope viewing begins at 7 p.m.  Regardless of the weather on January 2, join us indoors in our planetarium theater for “The Sky Tonight”.  Showtime is at 7 p.m. 

This free, indoor star program will introduce you to the current night sky, the planets, and the seasonal constellations. Doors open 15 minutes before show time. Shows begins at 7 p.m. Sorry, no late admissions due to safety issues in the darkened theater.

The St. Louis Astronomical Society hosts the monthly Star Parties at the Science Center which are held on the first Friday of each month. Our Monthly Star Parties are open to the public and free of charge.  For more information about the St. Louis Astronomical Society visit their website at www.slasonline.org

 

Battlestar Scienza


Join us at our December First Friday, Battlestar Galactica - So Say We All, and try out our new experience - Battlestar Scienza! 

Battlestar Scienza is a live-action interactive experience in which you and your fellow crewmates will determine the fate of human- and cylon-kind by completing missions, gathering intelligence and making your voices heard throughout the evening. At 9:15 pm, you will take part in electing the next President of Scienza, a decision that will have lasting ramifications.

Each First Friday visitor will be given an Allegiance (Human or Cylon) and an Assignment (Scientist, Pilot, Engineer, etc.). Listen for announcements throughout the evening that call for your Assignment. These Assignment-specific missions will challenge participants to complete a task to gain intelligence. This intelligence will help identify which candidate for President has humankind’s best interests at heart. Be wary of what you hear, though! Cylons will attempt to divert missions and feed false intelligence throughout the evening.

  • Join your crewmates at 6:30pm at Center Stage to hear the Opening Statements for your presidential candidates.
  • Voting for the evening will take place using Twitter and Instagram.

Week of Monday, November 17

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, November 17.  All times are given as local St. Louis time (Central Standard Time).  For definitions of terminology used in the night sky update, click the highlighted text.

Information updated weekly or as needed.

Join us for our next star party, Friday, December 5, 2014 held in association with the St. Louis Astronomical Society. For details, see the information at the bottom of this page.

The Sun and the Moon

Sunrise is at 6:45 a.m. on Monday, November 17 and sunset is at 4:46 p.m. providing us with about 10 hours of daylight.  Even after sunset, the light from the Sun will still dimly illuminate our sky for about 1.5 hours.  This period of time is called twilight, which ends around 6:18 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 11:46 a.m. this week. 

 

Day

Sunrise

Sunset

10 Nov

6:45 a.m.

4:46 p.m.

11 Nov

6:46 a.m.

4:46 p.m.

12 Nov

6:47 a.m.

4:45 p.m.

13 Nov

6:49 a.m.

4:44 p.m.

14 Nov

6:50 a.m.

4:44 p.m.

15 Nov

6:51 a.m.

4:43 p.m.

16 Nov

6:52 a.m.

4:43 p.m.

         

Moonrise for Monday, November 17 occurs at 1:50 a.m. and moonset will occur at 2:07 p.m.  On Monday, November 17 the Moon will be exhibiting a waning crescent phase with about 22% of the lunar disk illuminated.  New moon occurs on November 22 at 6:33 a.m.  

International Space Station (ISS) Observing

Visible passes of ISS from St. Louis this week occur during the morning hours.  The best of these is on the morning of November 23.  Learn more about this pass and other this week in the table below.

Catch ISS flying over St. Louis in the morning hours starting Monday, November 17. 

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

21 Nov

-0.8

05:55:54

10

N

05:57:26

13

NNE

05:58:59

10

NE

23 Nov

-1.2

05:52:45

10

NNW

05:55:19

20

NNE

05:57:52

10

ENE

24 Nov

-0.9

05:05:07

15

NNE

05:05:27

15

NNE

05:07:27

10

ENE

 

Magnitude (Mag): The Measure of brightness for a celestial object.  The lower the value is, the brighter the object will be.

Altitude (Alt):  The angle of a celestial object measured upwards from the observer’s horizon.

Azimuth (Az):  The direction of a celestial object, measured clockwise from an observer’s location with north being 0°, east being 90°, south being 180° and west being 270°. 

For information about ISS flyovers and other visible satellites, visit www.heavens-above.com

Detailed information regarding all unmanned exploration of our universe, missions past, present, and planned, can be found at Jet Propulsion Laboratories:

http://www.jpl.nasa.gov/

The Planets Visible Without A Telescope

Mercury

The most elusive naked eye planet has returned to the morning skies just before sunrise.  It will be difficult to see unless you find a clear eastern horizon free of trees and buildings.  If you have any kind of tree cover east of you Mercury will be too low in the sky.  This will be the best morning apparition of Mercury this year and will get better as the month goes on.

Mars

Mars is now in the constellation Sagittarius and rises before the Sun sets.  Mars will be seen in the southwestern skies about 20 minutes after sunset.  Mars will set by 8:04 p.m. 

Jupiter

The largest planet in the solar system has returned to our evening skies.  Jupiter can be found rising by 11:00 p.m. and will be easily visible by 11:30 p.m. in the eastern sky.  Jupiter can currently be found in the constellation Leo the Lion.    

Uranus and Neptune Opposition 2014

The two most distant planets in our solar system will be at their best for the next couple of months.  Neptune has already reached opposition and Uranus will reach opposition on October 7, 2014.  The opposition of a planet is when it is in opposition with the Sun.  What that means is a planet or other body such as an asteroid is seen on the opposite side of the Earth than the Sun is.  From our perspective this is when an object is at its brightest and also coincides with the object’s closest approach to the Earth.  Only objects further from the Sun than we are can be in opposition. 

Of the two planets Uranus will be the brightest.  Uranus is already appearing as a 5.8 magnitude object and will continue to brighten until October 7.  Uranus is normally a planet that requires binoculars to be seen but when the planet is nearing opposition dark sky observers can see it with the unaided eye.  Through telescopes observers will resolve Uranus into a small disk shaped object that may display a slight greenish blue color.  Large telescopes using high magnifications up to 300x might be able to discern dark and light patches called albedo features.  These features require large aperture telescopes and better than average viewing conditions to be seen. 

Uranus is currently in the constellation Pisces.  Pisces is very difficult to see in light polluted skies so it is better to start with the Great Square of Autumn.  This asterism connects the constellations Andromeda and Pegasus all of which will be seen high in the eastern sky by 10:00 p.m.  As the Great Square sits high in the east if you follow a line connecting the stars Scheat (Beta Peg) through Algenib (Gamma Peg) about the same distance that lays between the two stars you will find three stars the stand next to one another in a straight line.  The brightest of these stars is Delta Piscium.  Uranus is about four degrees south of these stars.  You will need either a desktop planetarium program or detailed star chart to help you pinpoint which star like object is Uranus. 

http://www.iau.org/static/public/constellations/gif/PSC.gif

http://www.iau.org/static/public/constellations/gif/PEG.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Neptune reached opposition on August 29, 2014.  It is now at its peak brightness of 7.8 magnitude.  This means that you will need at least binoculars to see this distant planet even when it is at its brightest.  Through binoculars Neptune will appear as a dim star like object in the constellation Aquarius.  To find Neptune first locate the bright star Fomalhaut.  About 6 to 10 degrees north of Fomalhaut you will find six bright stars that are shaped like a hyperboloid.  Scanning the sky further north you will find the star Sigma Aquarii.  Neptune will be just east of this star.      

Using a telescope most will see a star like object that when magnified enough will reveal a greyish blue disk.  Using a large telescope and high magnification up to 300x it may be possible to detect albedo features and Neptune largest moon Triton.  Triton will appear as a dim star right next to Neptune.

Like Uranus Neptune will require some kind of astronomy software of a detailed map to find.  As we pass by these planets in our orbit see if you can detect there shift amongst the background stars.  Below are a few links that will be helpful in locating Neptune and the stars mentioned above.

http://www.iau.org/static/public/constellations/gif/AQR.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Constellation of the Month

Each month we will highlight one constellation and some of the objects that can be found within the boundaries of that constellation.  At the start of the month we will list only a few of these objects and each week we will add another to the list.  Some objects will be visible to the unaided eye and some may require a telescope.  Many of the objects listed will require a map of the sky to find or may require repeat observations to notice various properties.  Links to star charts and other information that will be useful in identifying the objects listed will be given at the end of each week’s section. 

This month we will explore the constellation Pegasus.  Pegasus is the famous flying horse that appears in the story of Perseus.  Pegasus was the offspring of Poseidon and Medusa who was born to the world once Medusa was slain in battle by Perseus.  Pegasus is said to have aided Perseus in his fight against the Titan Cetus and also was eventually awarded a place in the stables of Mt. Olympus tasked with caring the lightning bolts of Zeus. 

To find Pegasus first locate the Great Square of Autumn from our list of asterisms we covered last month.  The Great Square connects the constellations Andromeda to Pegasus and will be best seen nearly over head after 10 p.m. 

http://www.iau.org/static/public/constellations/gif/PEG.gif

As for the individual objects we will cover this month Pegasus can be seen as a bit sparse for the beginning observer.  Pegasus has many fine targets to look for however they are a little more on the advanced end of the observing challenges.  All the targets we will talk about this month can be seen in binoculars of varying apertures however they will require the ability to recognize faint and complex star fields to confirm that the object was seen.  Even though I would describe these as advanced observing projects that does not mean the beginning observer cannot find them.  In fact these objects will help push your observing abilities and help refine your observing skills. 

The first object we will cover in November is the globular cluster Messier 15.  This will be the only easy object to find that we cover this month in the night sky update.  Messier 15 is one of the roughly 160 globular clusters found in the Milky Way Galaxy.  Globular clusters are the densely packed ancient star clusters that orbit the outer halo and center of our galaxy.  Messier 15 contains over 100,000 stars that lie at a distance of about 33,000 light years. 

Also of interest is that Messier 15 is one of the prototype globular clusters that exhibit something called core collapse.  The core collapse of a globular cluster is the result of how its stars orbit within the cluster and interact with one another.  Due to a transfer of energy, stars near the core begin to migrate further into the core while the stars associated with the cluster’s halo migrate further out.  The star populations in the core of globular clusters that exhibit core collapse are nearly ten billion times more densely packed than that of the Sun’s neighborhood in the Milky Way.  Visually what that means is the globular cluster will have increasing magnitudes as you look from its edge to its core. 

To find Messier 15 first locate the Great Square of Autumn.  The southwestern most star in the square is called Markab.  From this star if you continue scanning southwest you will find the stars Homan and Theta Pegasi.  From Theta Pegasi look about 7 degrees to the northwest and you will find the star Enif.  Continuing along this same path you will find Messier 15 about 2 to 3 degrees to the northwest of Enif.  It will appear as a fuzzy star.  It is listed at about 6.2 magnitude and will appear to cover about 7 arc minutes of sky.  Due to the core collapse aspect of this globular many of its member stars cover an area of about 21 arc minutes but will remain unseen due to their great distance from us. 

http://www.iau.org/static/public/constellations/gif/PEG.gif 

The object for the week of November 10 is the star 51 Pegasi.  At first glance this is a star that would not seem to warrant a lot of attention.  It is a G-class dwarf star that is similar in size to the Sun (a bit bigger).  It is a main sequence star that is fusing hydrogen at its core; it has a high metallicity and would be considered middle aged for its temperature and mass.  In all 51 Pegasi is very similar to the Sun.  All of these traits that may seem to make 51 Pegasi appear as an average generic star are what makes 51 Pegasi an ideal candidate for a star that has planets.  In 1995 this idea was confirmed when scientists using an observational method called radial velocity discovered a Jupiter size body orbiting the star. 

The potential exoplanet orbiting 51 Pegasi has been formally named 51 Pegasi b with some calling it Bellerophon, who was the ancient Greek hero who slew the Chimera with the assistance of Pegasus.  This was the first exoplanet discovered orbiting a main sequence star.  51 Peg b is a body that orbits 51 Pegasi at a distance of roughly 0.05 AU (4.65 million miles).  It is tidally locked which means the same side of the body is always pointed at the star.  Due to this the side that is pointed at the star would have temperatures reaching 1,800 degrees Fahrenheit. 

There has been some thought that 51 Peg b is a brown dwarf star.  This would suggest that 51 Pegasi is a binary star system.  The reason for this is at the time of 51 Peg b’s discovery a Jupiter sized body forming so close to its parent star seemed highly unlikely.  Since the discovery of 51 Peg b a number of other Jupiter sized planets have been discovered orbiting their stars at similar close distances.  These exoplanets have been called Hot Jupiters.  Most view 51 Peg b as an exoplanet however there is still some debate on the issue.

To find 51 Pegasi first locate the Great Square of Autumn.  Next locate the two stars that make up the western half of the square, Alpha and Beta Pegasi.  About halfway between these two stars there will be two 5th magnitude stars.  The western of these is 51 Pegasi.  The map I will link below shows 51 Pegasi but it does not label it.  So for confirmation you will need to locate a more detailed map of the sky or use planetarium software such as Stellarium.  This software is free to download and is an extremely useful tool for the backyard stargazer. 

http://www.iau.org/static/public/constellations/gif/PEG.gif

The object for the week of November 17 is the supergiant star Enif.  Also known as Epsilon Pegasi this K-class star (orange) is the brightest star in Pegasus.  Enif marks the nose of Pegasus and is one of the guide stars we used to find Messier 15 earlier this month.  Enif is of interest for a number of reasons.  First it is a highly evolved star that is in its supergiant phase.  It is likely beginning to fuse helium into carbon and oxygen and may move on to heavier elements on its way to an explosive death called a supernova.  Enif will likely exist for another few million years before it explodes or becomes a rare oxygen and neon white dwarf star.   

Another reason Enif is of interest is because it is a variable star.  Unlike other variable stars covered in the night sky update, Enif is a variable that does not have a predictable period of variance.  Enif is what has been called a slow LC irregular variable star.  On a few rare occasions Enif has been seen to brighten by about 2 magnitudes for a short period of time (minutes).  These types of variable stars are not well understood due to their variable nature being unpredictable and are very difficult to catch.  It is believed that stars like this have similar flare events as the Sun exhibits only on a much larger scale.  The cause of these enormous flares is not understood and it goes to show that astronomers still have a lot to learn about how stars behave.  If you have an interest in observing this rare variable star it will take dedication and patience and perhaps even a journey into the world of video astronomy.  Video ccd cameras allow an observer to document large periods of time.  Video astronomy also has the benefit of costing far less than a traditional still or FITS ccd camera that many astrophotographers would use.     

To find Enif first locate the Great Square of Autumn.  From the lower right corner of the square look for the bright stars Zeta and Theta Pegasi.  These two stars form the neck of Pegasus and will extend to the southwest in a long straight line.  From Theta Pegasi look to the northwest and you will find Enif.  This star will not be a normal target for many observers however keeping it in mind while you are observing during the fall and winter months may provide you with an exciting opportunity to see a truly rare sight in the sky.  Use the map linked below to help you find Enif and the guide stars listed above. 

http://www.iau.org/static/public/constellations/gif/PEG.gif       

Our next Star Party will be held on Friday, December 5, 2014, from dusk until 10 p.m.

Weather permitting, the St. Louis Astronomical Society and the Science Center will set up a number of telescopes outdoors and be on-hand to answer your questions.  Telescope viewing begins at 8:00 p.m.  Regardless of the weather on December 5, join us indoors in our planetarium theater for “The Sky Tonight”.  Showtime is at 7 p.m.
This free, indoor star program will introduce you to the current night sky, the planets, and the seasonal constellations. Doors open 15 minutes before show time. Shows begins at 7 p.m. Sorry, no late admissions due to safety issues in the darkened theater.

The St. Louis Astronomical Society hosts the monthly Star Parties at the Science Center which are held on the first Friday of each month. Our Monthly Star Parties are open to the public and free of charge.  For more information about the St. Louis Astronomical Society visit their website at www.slasonline.org

Week of Monday, November 10

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, November 10.  All times are given as local St. Louis time (Central Standard Time).  For definitions of terminology used in the night sky update, click the highlighted text.

Information updated weekly or as needed.

Join us for our next star party, Friday, December 5, 2014 held in association with the St. Louis Astronomical Society. For details, see the information at the bottom of this page.

The Sun and the Moon

Sunrise is at 6:38 a.m. on Monday, November 10 and sunset is at 4:52 p.m. providing us with about 10.5 hours of daylight.  Even after sunset, the light from the Sun will still dimly illuminate our sky for about 1.5 hours.  This period of time is called twilight, which ends around 6:23 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 11:45 a.m. this week.  

Day

Sunrise

Sunset

10 Nov

6:38 a.m.

4:52 p.m.

11 Nov

6:39 a.m.

4:51 p.m.

12 Nov

6:40 a.m.

4:50 p.m.

13 Nov

6:41 a.m.

4:49 p.m.

14 Nov

6:42 a.m.

4:49 p.m.

15 Nov

6:43 a.m.

4:48 p.m.

16 Nov

6:44 a.m.

4:47 p.m.

        

Moonrise for Monday, November 10 occurs at 8:20 p.m. and moonset will occur at 10:45 a.m. on the following day.  On Monday, November 10 the Moon will be exhibiting a waning gibbous phase with about 84% of the lunar disk illuminated.  Last quarter moon occurs on November 14 at 9:17 a.m.  

International Space Station (ISS) Observing

Visible passes of ISS from St. Louis this week occur during the morning hours.  The best of these is on the morning of November 12. 

Catch ISS flying over St. Louis in the morning hours starting Monday, November 10. 

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

11 Nov

-1.3

04:29:21

28

ESE

04:29:21

28

ESE

04:31:49

10

ENE

11 Nov

-2.3

06:02:36

10

W

06:05:32

29

NNW

06:08:29

10

NNE

12 Nov

-3.0

05:15:32

44

WNW

05:15:58

48

NW

05:19:12

10

NE

13 Nov

-0.9

04:28:35

20

NE

04:28:35

20

NE

04:29:46

10

NE

13 Nov

-1.4

06:01:27

10

WNW

06:03:31

16

NNW

06:05:41

10

NNE

14 Nov

-1.6

05:14:19

21

NNW

05:14:19

21

NNW

05:16:28

10

NNE

15 Nov

-0.2

04:27:02

11

NE

04:27:02

11

NE

04:27:08

10

NE

15 Nov

-0.9

06:00:42

10

NNW

06:01:33

11

NNW

06:02:25

10

N

16 Nov

-0.8

05:12:28

13

N

05:12:28

13

N

05:13:22

10

NNE

 

Magnitude (Mag): The Measure of brightness for a celestial object.  The lower the value is, the brighter the object will be.

Altitude (Alt):  The angle of a celestial object measured upwards from the observer’s horizon.

Azimuth (Az):  The direction of a celestial object, measured clockwise from an observer’s location with north being 0°, east being 90°, south being 180° and west being 270°. 

For information about ISS flyovers and other visible satellites, visit www.heavens-above.com

Detailed information regarding all unmanned exploration of our universe, missions past, present, and planned, can be found at Jet Propulsion Laboratories:

http://www.jpl.nasa.gov/

The Planets Visible Without A Telescope

Mars

Mars is now in the constellation Sagittarius and rises before the Sun sets.  Mars will be seen in the southwestern skies about 20 minutes after sunset.  Mars will set by 8:06 p.m. 

Jupiter

The largest planet in the solar system is visible once again in the morning skies.  Jupiter can be found rising by 11:25 p.m. and will be easily visible by 12:00 a.m. in the eastern sky.  Jupiter can currently be found in the constellation Leo the Lion.        

Uranus and Neptune Opposition 2014

The two most distant planets in our solar system will be at their best for the next couple of months.  Neptune has already reached opposition and Uranus will reach opposition on October 7, 2014.  The opposition of a planet is when it is in opposition with the Sun.  What that means is a planet or other body such as an asteroid is seen on the opposite side of the Earth than the Sun is.  From our perspective this is when an object is at its brightest and also coincides with the object’s closest approach to the Earth.  Only objects further from the Sun than we are can be in opposition. 

Of the two planets Uranus will be the brightest.  Uranus is already appearing as a 5.8 magnitude object and will continue to brighten until October 7.  Uranus is normally a planet that requires binoculars to be seen but when the planet is nearing opposition dark sky observers can see it with the unaided eye.  Through telescopes observers will resolve Uranus into a small disk shaped object that may display a slight greenish blue color.  Large telescopes using high magnifications up to 300x might be able to discern dark and light patches called albedo features.  These features require large aperture telescopes and better than average viewing conditions to be seen. 

Uranus is currently in the constellation Pisces.  Pisces is very difficult to see in light polluted skies so it is better to start with the Great Square of Autumn.  This asterism connects the constellations Andromeda and Pegasus all of which will be seen high in the eastern sky by 10:00 p.m.  As the Great Square sits high in the east if you follow a line connecting the stars Scheat (Beta Peg) through Algenib (Gamma Peg) about the same distance that lays between the two stars you will find three stars the stand next to one another in a straight line.  The brightest of these stars is Delta Piscium.  Uranus is about four degrees south of these stars.  You will need either a desktop planetarium program or detailed star chart to help you pinpoint which star like object is Uranus. 

http://www.iau.org/static/public/constellations/gif/PSC.gif

http://www.iau.org/static/public/constellations/gif/PEG.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Neptune reached opposition on August 29, 2014.  It is now at its peak brightness of 7.8 magnitude.  This means that you will need at least binoculars to see this distant planet even when it is at its brightest.  Through binoculars Neptune will appear as a dim star like object in the constellation Aquarius.  To find Neptune first locate the bright star Fomalhaut.  About 6 to 10 degrees north of Fomalhaut you will find six bright stars that are shaped like a hyperboloid.  Scanning the sky further north you will find the star Sigma Aquarii.  Neptune will be just east of this star.      

Using a telescope most will see a star like object that when magnified enough will reveal a greyish blue disk.  Using a large telescope and high magnification up to 300x it may be possible to detect albedo features and Neptune largest moon Triton.  Triton will appear as a dim star right next to Neptune.

Like Uranus Neptune will require some kind of astronomy software of a detailed map to find.  As we pass by these planets in our orbit see if you can detect there shift amongst the background stars.  Below are a few links that will be helpful in locating Neptune and the stars mentioned above.

http://www.iau.org/static/public/constellations/gif/AQR.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Constellation of the Month

Each month we will highlight one constellation and some of the objects that can be found within the boundaries of that constellation.  At the start of the month we will list only a few of these objects and each week we will add another to the list.  Some objects will be visible to the unaided eye and some may require a telescope.  Many of the objects listed will require a map of the sky to find or may require repeat observations to notice various properties.  Links to star charts and other information that will be useful in identifying the objects listed will be given at the end of each week’s section. 

This month we will explore the constellation Pegasus.  Pegasus is the famous flying horse that appears in the story of Perseus.  Pegasus was the offspring of Poseidon and Medusa who was born to the world once Medusa was slain in battle by Perseus.  Pegasus is said to have aided Perseus in his fight against the Titan Cetus and also was eventually awarded a place in the stables of Mt. Olympus tasked with caring the lightning bolts of Zeus. 

To find Pegasus first locate the Great Square of Autumn from our list of asterisms we covered last month.  The Great Square connects the constellations Andromeda to Pegasus and will be best seen nearly over head after 10 p.m. 

http://www.iau.org/static/public/constellations/gif/PEG.gif

As for the individual objects we will cover this month Pegasus can be seen as a bit sparse for the beginning observer.  Pegasus has many fine targets to look for however they are a little more on the advanced end of the observing challenges.  All the targets we will talk about this month can be seen in binoculars of varying apertures however they will require the ability to recognize faint and complex star fields to confirm that the object was seen.  Even though I would describe these as advanced observing projects that does not mean the beginning observer cannot find them.  In fact these objects will help push your observing abilities and help refine your observing skills. 

The first object we will cover in November is the globular cluster Messier 15.  This will be the only easy object to find that we cover this month in the night sky update.  Messier 15 is one of the roughly 160 globular clusters found in the Milky Way Galaxy.  Globular clusters are the densely packed ancient star clusters that orbit the outer halo and center of our galaxy.  Messier 15 contains over 100,000 stars that lie at a distance of about 33,000 light years. 

Also of interest is that Messier 15 is one of the prototype globular clusters that exhibit something called core collapse.  The core collapse of a globular cluster is the result of how its stars orbit within the cluster and interact with one another.  Due to a transfer of energy, stars near the core begin to migrate further into the core while the stars associated with the cluster’s halo migrate further out.  The star populations in the core of globular clusters that exhibit core collapse are nearly ten billion times more densely packed than that of the Sun’s neighborhood in the Milky Way.  Visually what that means is the globular cluster will have increasing magnitudes as you look from its edge to its core. 

To find Messier 15 first locate the Great Square of Autumn.  The southwestern most star in the square is called Markab.  From this star if you continue scanning southwest you will find the stars Homan and Theta Pegasi.  From Theta Pegasi look about 7 degrees to the northwest and you will find the star Enif.  Continuing along this same path you will find Messier 15 about 2 to 3 degrees to the northwest of Enif.  It will appear as a fuzzy star.  It is listed at about 6.2 magnitude and will appear to cover about 7 arc minutes of sky.  Due to the core collapse aspect of this globular many of its member stars cover an area of about 21 arc minutes but will remain unseen due to their great distance from us. 

http://www.iau.org/static/public/constellations/gif/PEG.gif 

The object for the week of November 10 is the star 51 Pegasi.  At first glance this is a star that would not seem to warrant a lot of attention.  It is a G-class dwarf star that is similar in size to the Sun (a bit bigger).  It is a main sequence star that is fusing hydrogen at its core; it has a high metallicity and would be considered middle aged for its temperature and mass.  In all 51 Pegasi is very similar to the Sun.  All of these traits that may seem to make 51 Pegasi appear as an average generic star are what makes 51 Pegasi an ideal candidate for a star that has planets.  In 1995 this idea was confirmed when scientists using an observational method called radial velocity discovered a Jupiter size body orbiting the star. 

The potential exoplanet orbiting 51 Pegasi has been formally named 51 Pegasi b with some calling it Bellerophon, who was the ancient Greek hero who slew the Chimera with the assistance of Pegasus.  This was the first exoplanet discovered orbiting a main sequence star.  51 Peg b is a body that orbits 51 Pegasi at a distance of roughly 0.05 AU (4.65 million miles).  It is tidally locked which means the same side of the body is always pointed at the star.  Due to this the side that is pointed at the star would have temperatures reaching 1,800 degrees Fahrenheit. 

There has been some thought that 51 Peg b is a brown dwarf star.  This would suggest that 51 Pegasi is a binary star system.  The reason for this is at the time of 51 Peg b’s discovery a Jupiter sized body forming so close to its parent star seemed highly unlikely.  Since the discovery of 51 Peg b a number of other Jupiter sized planets have been discovered orbiting their stars at similar close distances.  These exoplanets have been called Hot Jupiters.  Most view 51 Peg b as an exoplanet however there is still some debate on the issue.

To find 51 Pegasi first locate the Great Square of Autumn.  Next locate the two stars that make up the western half of the square, Alpha and Beta Pegasi.  About halfway between these two stars there will be two 5th magnitude stars.  The western of these is 51 Pegasi.  The map I will link below shows 51 Pegasi but it does not label it.  So for confirmation you will need to locate a more detailed map of the sky or use planetarium software such as Stellarium.  This software is free to download and is an extremely useful tool for the backyard stargazer. 

http://www.iau.org/static/public/constellations/gif/PEG.gif            

Our next Star Party will be held on Friday, December 5, 2014, from dusk until 10 p.m.

Weather permitting, the St. Louis Astronomical Society and the Science Center will set up a number of telescopes outdoors and be on-hand to answer your questions.  Telescope viewing begins at 8:00 p.m.  Regardless of the weather on December 5, join us indoors in our planetarium theater for “The Sky Tonight”.  Showtime is at 7 p.m.
This free, indoor star program will introduce you to the current night sky, the planets, and the seasonal constellations. Doors open 15 minutes before show time. Shows begins at 7 p.m. Sorry, no late admissions due to safety issues in the darkened theater.

The St. Louis Astronomical Society hosts the monthly Star Parties at the Science Center which are held on the first Friday of each month. Our Monthly Star Parties are open to the public and free of charge.  For more information about the St. Louis Astronomical Society visit their website at www.slasonline.org

Week of November 3, 2014

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, November 3.  All times are given as local St. Louis time (Central Standard Time).  For definitions of terminology used in the night sky update, click the highlighted text.

Information updated weekly or as needed.

 Join us for our next star party, Friday, November 7, 2014 held in association with the St. Louis Astronomical Society. For details, see the information at the bottom of this page.

The Sun and the Moon

Sunrise is at 6:30 a.m. on Monday, November 3 and sunset is at 4:59 p.m. providing us with about 10.5 hours of daylight.  Even after sunset, the light from the Sun will still dimly illuminate our sky for about 1.5 hours.  This period of time is called twilight, which ends around 6:26 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 11:45 p.m. this week. 

Day

Sunrise

Sunset

03 Nov

6:30 a.m.

4:59 p.m.

04 Nov

6:31 a.m.

4:58 p.m.

05 Nov

6:32 a.m.

4:57 p.m.

06 Nov

6:33 a.m.

4:56 p.m.

07 Nov

6:34 a.m.

4:55 p.m.

08 Nov

6:35 a.m.

4:54 p.m.

09 Nov

6:37 a.m.

4:53 p.m.

Moonrise for Monday, November 3 occurs at 3:05 p.m. and moonset will occur at 3:51 a.m. on the following day.  On Monday, November 3 the Moon will be exhibiting a waxing gibbous phase with about 87% of the lunar disk illuminated.  Full moon occurs on November 6 at 4:23 p.m.  November’s full moon is known as the Full Beaver Moon.

International Space Station (ISS) Observing

Visible passes of ISS from St. Louis this week occur during the morning hours.  The best of these is on the mornings of November 9 and 10. 

Catch ISS flying over St. Louis in the morning hours starting Monday, November 3. 

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

07 Nov

-1.5

06:06:44

10

SSW

06:09:47

35

SE

06:12:51

10

ENE

08 Nov

-0.5

05:18:09

10

S

05:20:35

19

SE

05:23:02

10

E

09 Nov

-3.3

06:04:22

10

SW

06:07:40

74

NW

06:10:59

10

NE

10 Nov

-2.7

05:15:49

16

SW

05:18:18

58

SE

05:21:34

10

ENE

Magnitude (Mag): The Measure of brightness for a celestial object.  The lower the value is, the brighter the object will be.

Altitude (Alt):  The angle of a celestial object measured upwards from the observer’s horizon.

Azimuth (Az):  The direction of a celestial object, measured clockwise from an observer’s location with north being 0°, east being 90°, south being 180° and west being 270°.

For information about ISS flyovers and other visible satellites, visit www.heavens-above.com

Detailed information regarding all unmanned exploration of our universe, missions past, present, and planned, can be found at Jet Propulsion Laboratories:

http://www.jpl.nasa.gov/

The Planets Visible Without A Telescope

Mars

Mars is now in the constellation Sagittarius and rises before the Sun sets.  Mars will be seen in the southwestern skies about 20 minutes after sunset.  Mars will set by 8:09 p.m. 

Jupiter

The largest planet in the solar system is visible once again in the morning skies.  Jupiter can be found rising by 11:49 a.m. and will be easily visible by 12:30 a.m. in the eastern sky.  Jupiter can currently be found in the constellation Leo the Lion.    

Uranus and Neptune Opposition 2014

The two most distant planets in our solar system will be at their best for the next couple of months.  Neptune has already reached opposition and Uranus will reach opposition on October 7, 2014.  The opposition of a planet is when it is in opposition with the Sun.  What that means is a planet or other body such as an asteroid is seen on the opposite side of the Earth than the Sun is.  From our perspective this is when an object is at its brightest and also coincides with the object’s closest approach to the Earth.  Only objects further from the Sun than we are can be in opposition. 

Of the two planets Uranus will be the brightest.  Uranus is already appearing as a 5.8 magnitude object and will continue to brighten until October 7.  Uranus is normally a planet that requires binoculars to be seen but when the planet is nearing opposition dark sky observers can see it with the unaided eye.  Through telescopes observers will resolve Uranus into a small disk shaped object that may display a slight greenish blue color.  Large telescopes using high magnifications up to 300x might be able to discern dark and light patches called albedo features.  These features require large aperture telescopes and better than average viewing conditions to be seen. 

Uranus is currently in the constellation Pisces.  Pisces is very difficult to see in light polluted skies so it is better to start with the Great Square of Autumn.  This asterism connects the constellations Andromeda and Pegasus all of which will be seen high in the eastern sky by 10:00 p.m.  As the Great Square sits high in the east if you follow a line connecting the stars Scheat (Beta Peg) through Algenib (Gamma Peg) about the same distance that lays between the two stars you will find three stars the stand next to one another in a straight line.  The brightest of these stars is Delta Piscium.  Uranus is about four degrees south of these stars.  You will need either a desktop planetarium program or detailed star chart to help you pinpoint which star like object is Uranus. 

http://www.iau.org/static/public/constellations/gif/PSC.gif

http://www.iau.org/static/public/constellations/gif/PEG.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Neptune reached opposition on August 29, 2014.  It is now at its peak brightness of 7.8 magnitude.  This means that you will need at least binoculars to see this distant planet even when it is at its brightest.  Through binoculars Neptune will appear as a dim star like object in the constellation Aquarius.  To find Neptune first locate the bright star Fomalhaut.  About 6 to 10 degrees north of Fomalhaut you will find six bright stars that are shaped like a hyperboloid.  Scanning the sky further north you will find the star Sigma Aquarii.  Neptune will be just east of this star.       

Using a telescope most will see a star like object that when magnified enough will reveal a greyish blue disk.  Using a large telescope and high magnification up to 300x it may be possible to detect albedo features and Neptune largest moon Triton.  Triton will appear as a dim star right next to Neptune.

Like Uranus Neptune will require some kind of astronomy software of a detailed map to find.  As we pass by these planets in our orbit see if you can detect there shift amongst the background stars.  Below are a few links that will be helpful in locating Neptune and the stars mentioned above.

http://www.iau.org/static/public/constellations/gif/AQR.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Constellation of the Month

Each month we will highlight one constellation and some of the objects that can be found within the boundaries of that constellation.  At the start of the month we will list only a few of these objects and each week we will add another to the list.  Some objects will be visible to the unaided eye and some may require a telescope.  Many of the objects listed will require a map of the sky to find or may require repeat observations to notice various properties.  Links to star charts and other information that will be useful in identifying the objects listed will be given at the end of each week’s section. 

This month we will explore the constellation Pegasus.  Pegasus is the famous flying horse that appears in the story of Perseus.  Pegasus was the offspring of Poseidon and Medusa who was born to the world once Medusa was slain in battle by Perseus.  Pegasus is said to have aided Perseus in his fight against the Titan Cetus and also was eventually awarded a place in the stables of Mt. Olympus tasked with caring the lightning bolts of Zeus. 

To find Pegasus first locate the Great Square of Autumn from our list of asterisms we covered last month.  The Great Square connects the constellations Andromeda to Pegasus and will be best seen nearly over head after 10 p.m. 

http://www.iau.org/static/public/constellations/gif/PEG.gif

As for the individual objects we will cover this month Pegasus can be seen as a bit sparse for the beginning observer.  Pegasus has many fine targets to look for however they are a little more on the advanced end of the observing challenges.  All the targets we will talk about this month can be seen in binoculars of varying apertures however they will require the ability to recognize faint and complex star fields to confirm that the object was seen.  Even though I would describe these as advanced observing projects that does not mean the beginning observer cannot find them.  In fact these objects will help push your observing abilities and help refine your observing skills. 

The first object we will cover in November is the globular cluster Messier 15.  This will be the only easy object to find that we cover this month in the night sky update.  Messier 15 is one of the roughly 160 globular clusters found in the Milky Way Galaxy.  Globular clusters are the densely packed ancient star clusters that orbit the outer halo and center of our galaxy.  Messier 15 contains over 100,000 stars that lie at a distance of about 33,000 light years. 

Also of interest is that Messier 15 is one of the prototype globular clusters that exhibit something called core collapse.  The core collapse of a globular cluster is the result of how its stars orbit within the cluster and interact with one another.  Due to a transfer of energy, stars near the core begin to migrate further into the core while the stars associated with the cluster’s halo migrate further out.  The star populations in the core of globular clusters that exhibit core collapse are nearly ten billion times more densely packed than that of the Sun’s neighborhood in the Milky Way.  Visually what that means is the globular cluster will have increasing magnitudes as you look from its edge to its core. 

To find Messier 15 first locate the Great Square of Autumn.  The southwestern most star in the square is called Markab.  From this star if you continue scanning southwest you will find the stars Homan and Theta Pegasi.  From Theta Pegasi look about 7 degrees to the northwest and you will find the star Enif.  Continuing along this same path you will find Messier 15 about 2 to 3 degrees to the northwest of Enif.  It will appear as a fuzzy star.  It is listed at about 6.2 magnitude and will appear to cover about 7 arc minutes of sky.  Due to the core collapse aspect of this globular many of its member stars cover an area of about 21 arc minutes but will remain unseen due to their great distance from us. 

http://www.iau.org/static/public/constellations/gif/PEG.gif

Our next Star Party will be held on Friday, November 7, 2014, from dusk until 10 p.m.

Weather permitting, the St. Louis Astronomical Society and the Science Center will set up a number of telescopes outdoors and be on-hand to answer your questions.  Telescope viewing begins at 8:00 p.m.  Regardless of the weather on November 7, join us indoors in our planetarium theater for “The Sky Tonight”.  Showtime is at 7 p.m.

This free, indoor star program will introduce you to the current night sky, the planets, and the seasonal constellations. Doors open 15 minutes before show time. Shows begins at 7 p.m. Sorry, no late admissions due to safety issues in the darkened theater.

The St. Louis Astronomical Society hosts the monthly Star Parties at the Science Center which are held on the first Friday of each month. Our Monthly Star Parties are open to the public and free of charge.  For more information about the St. Louis Astronomical Society visit their website at www.slasonline.org

 

 

 

 

Week of Monday, October 27

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, October 27.  All times are given as local St. Louis time (Central Daylight Time).  For definitions of terminology used in the night sky update, click the highlighted text.

Information updated weekly or as needed.

Join us for our next star party, Friday, November 7, 2014 held in association with the St. Louis Astronomical Society. For details, see the information at the bottom of this page.

The Sun and the Moon

Sunrise is at 7:22 a.m. on Monday, October 27 and sunset is at 6:07 p.m. providing us with about 10.75 hours of daylight.  Even after sunset, the light from the Sun will still dimly illuminate our sky for about 1.5 hours.  This period of time is called twilight, which ends around 7:36 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 12:45 p.m. this week. 

Daylight savings time ends on November 2.  Remember to fall back one hour once we return to Central Standard Time on November 2, 2014.  Below you will find sunrise and sunset times for the rest of the week.  Note that all times in this table except for November 2 are in Central Daylight Time.   

Day

Sunrise

Sunset

27 Oct

7:22 a.m.

6:07 p.m.

28 Oct

7:24 a.m.

6:06 p.m.

29 Oct

7:25 a.m.

6:04 p.m.

30 Oct

7:26 a.m.

6:03 p.m.

31 Oct

7:27 a.m.

6:02 p.m.

01 Nov

7:28 a.m.

6:01 p.m.

02 Nov

6:29 a.m.

5:00 p.m.

        

Moonrise for Monday, October 27 occurs at 10:57 a.m. and moonset will occur at 9:14 p.m.  On Monday, October 27 the Moon will be exhibiting a waxing crescent phase with about 15% of the lunar disk illuminated.  First quarter moon occurs on October 30 at 9:48 p.m.

International Space Station (ISS) Observing

Visible passes of ISS from St. Louis this week occur during the evening hours.  The best of these is on the evening of October 28. 

Catch ISS flying over St. Louis in the evening hours starting Monday, October 27. 

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

27 Oct

-1.5

19:24:08

10

WNW

19:27:08

31

SW

19:30:06

10

SSE

28 Oct

-2.7

18:34:38

10

WNW

18:37:56

60

SW

18:41:13

10

SE

29 Oct

 0.1

19:24:00

10

WSW

19:24:52

11

SW

19:25:44

10

SW

30 Oct

-0.3

18:33:12

10

W

18:35:43

20

SW

18:38:13

10

S

 

Magnitude (Mag): The Measure of brightness for a celestial object.  The lower the value is, the brighter the object will be.

Altitude (Alt):  The angle of a celestial object measured upwards from the observer’s horizon.

Azimuth (Az):  The direction of a celestial object, measured clockwise from an observer’s location with north being 0°, east being 90°, south being 180° and west being 270°. 

For information about ISS flyovers and other visible satellites, visit www.heavens-above.com

Detailed information regarding all unmanned exploration of our universe, missions past, present, and planned, can be found at Jet Propulsion Laboratories:

http://www.jpl.nasa.gov/

The Planets Visible Without A Telescope

Mars

Mars is now in the constellation Ophiuchus and rises before the Sun sets.  Mars will be seen in the southwestern skies about 20 minutes after sunset.  Mars will set by 9:13 p.m. 

Jupiter

The largest planet in the solar system is visible once again in the morning skies.  Jupiter can be found rising by 1:16 a.m. and will be easily visible by 1:40 a.m.        

Uranus and Neptune Opposition 2014

The two most distant planets in our solar system will be at their best for the next couple of months.  Neptune has already reached opposition and Uranus will reach opposition on October 7, 2014.  The opposition of a planet is when it is in opposition with the Sun.  What that means is a planet or other body such as an asteroid is seen on the opposite side of the Earth than the Sun is.  From our perspective this is when an object is at its brightest and also coincides with the object’s closest approach to the Earth.  Only objects further from the Sun than we are can be in opposition. 

Of the two planets Uranus will be the brightest.  Uranus is already appearing as a 5.8 magnitude object and will continue to brighten until October 7.  Uranus is normally a planet that requires binoculars to be seen but when the planet is nearing opposition dark sky observers can see it with the unaided eye.  Through telescopes observers will resolve Uranus into a small disk shaped object that may display a slight greenish blue color.  Large telescopes using high magnifications up to 300x might be able to discern dark and light patches called albedo features.  These features require large aperture telescopes and better than average viewing conditions to be seen. 

Uranus is currently in the constellation Pisces.  Pisces is very difficult to see in light polluted skies so it is better to start with the Great Square of Autumn.  This asterism connects the constellations Andromeda and Pegasus all of which will be seen high in the eastern sky by 10:00 p.m.  As the Great Square sits high in the east if you follow a line connecting the stars Scheat (Beta Peg) through Algenib (Gamma Peg) about the same distance that lays between the two stars you will find three stars the stand next to one another in a straight line.  The brightest of these stars is Delta Piscium.  Uranus is about four degrees south of these stars.  You will need either a desktop planetarium program or detailed star chart to help you pinpoint which star like object is Uranus. 

http://www.iau.org/static/public/constellations/gif/PSC.gif

http://www.iau.org/static/public/constellations/gif/PEG.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Neptune reached opposition on August 29, 2014.  It is now at its peak brightness of 7.8 magnitude.  This means that you will need at least binoculars to see this distant planet even when it is at its brightest.  Through binoculars Neptune will appear as a dim star like object in the constellation Aquarius.  To find Neptune first locate the bright star Fomalhaut.  About 6 to 10 degrees north of Fomalhaut you will find six bright stars that are shaped like a hyperboloid.  Scanning the sky further north you will find the star Sigma Aquarii.  Neptune will be just east of this star.      

Using a telescope most will see a star like object that when magnified enough will reveal a greyish blue disk.  Using a large telescope and high magnification up to 300x it may be possible to detect albedo features and Neptune largest moon Triton.  Triton will appear as a dim star right next to Neptune.

Like Uranus Neptune will require some kind of astronomy software of a detailed map to find.  As we pass by these planets in our orbit see if you can detect there shift amongst the background stars.  Below are a few links that will be helpful in locating Neptune and the stars mentioned above.

http://www.iau.org/static/public/constellations/gif/AQR.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Constellation of the Month

Each month we will highlight one constellation and some of the objects that can be found within the boundaries of that constellation.  At the start of the month we will list only a few of these objects and each week we will add another to the list.  Some objects will be visible to the unaided eye and some may require a telescope.  Many of the objects listed will require a map of the sky to find or may require repeat observations to notice various properties.  Links to star charts and other information that will be useful in identifying the objects listed will be given at the end of each week’s section. 

This month we will once again forego a single constellation and discuss a number of different patterns.  This month we will work on finding some of the informal groupings of stars called asterisms.  These informal patterns can be large groups that contain multiple constellations or they can be small dim groupings that require a telescope to see. Many of them serve as useful markers in the sky that help you find dimmer and more difficult objects.  

The first asterism we will cover in October is the Summer Triangle.  This is one we have mentioned and used numerous times in the night sky update.  Last week in fact we used it in reference to finding Cygnus the Swan.  Other constellations that comprise this asterism are Lyra the Harp and Aquila the Eagle.  Inside the Summer Triangle we find the constellations Vulpecula the Fox, Sagitta the Arrow and just outside the eastern edge is Delphinus the Dolphin.  Scattered throughout these constellations are many gems for double star observers, numerous open star clusters and a number of nebulas.  The first step in finding all of these is taken by first locating the Summer Triangle.

Also of interest regarding the Summer Triangle is a Mission called Kepler.  This is a space telescope that steadily observed the patch of sky between Cygnus and Lyra.  What Kepler was looking for was the subtle changes in a star’s light due to the effects of a planet orbiting around it.  Thanks to the Kepler mission and other research programs scientists currently have 5,022 candidate exoplanets (planets orbiting other stars) of which 1,746 have been confirmed.  With these numbers scientists have estimated that there are likely as many planets as there are stars in the Milky Way galaxy if not more.  If you would like to learn more about Kepler and the hunt for exoplanets visit http://planetquest.jpl.nasa.gov/   

With a name like the Summer Triangle you would think that we would start losing this asterism soon as we approach winter.  Due to the longer nights we will continue to see the Summer Triangle for the rest of the year.  Tonight go outside and simply look straight up and you should see the three bright stars Deneb, Vega and Altair that define the triangle shape.  Once you can find this asterism grab some binocular and a reclined chair and just start scanning this part of the sky.  Dense star fields and numerous stars clusters will keep you busy for some time. 

The asterism we will cover for the week of October 6 is the Great Square of Autumn.  This is another asterism that can serve as a reference point or guide post in the sky.  Much like the Summer Triangle, the Great Square of Autumn can be used to find a number of constellations and other objects of interest.  The Great Square primarily consists of two constellations; Andromeda and Pegasus.  As most of the square is in Pegasus it is also called the Square of Pegasus.  The Great Square of Autumn can also help you find the constellations Piscis, Cetus, Aquarius, Lacerta and Equuleus. 

One of the more challenging objects the Great Square can help you find is the bright variable star Mira.  Mira is a long period variable that every 333 days or so will brighten from 10th magnitude up to about 3rd magnitude.  This change does not occur in one day but over the entire 333 day cycle.  The brightening of the Mira takes about 100 days and will take twice as long to fade back to minima.  Mira was one of the first variable stars other than bright supernovas or novae to be discovered and it certainly is one of the brightest.  Unfortunately Mira has already peaked in brightness and is already well into its slow downward fade for 2014. 

Mira is an M-class red giant star that is approximately 6 billion years old.  The variable nature of Mira is due to an internal pulsation which is a result of the unstable nature of the star.  The Sun will likely come to a similar state as it evolves into a red giant star in another 5 billion years.  Mira is one of the brightest stars in the constellation Cetus.  Depending on the map you use to find Mira you may find it labeled Omicron Ceti.  

http://www.iau.org/static/public/constellations/gif/CET.gif

Finding the Great Square of Autumn is simple but it does depend on what time you look for it.  After sunset the square will be seen low in the east looking more like a diamond.  At midnight it will be nearly overhead and before sunrise it will be found low in the west. 

For the rest of the month we will cover asterisms that are still helpful guides in the sky but they will be found in individual constellations and will require an optical device such as binoculars to see.

The asterism for the week of October 13 is the star cluster known as the ET cluster.  This group of roughly 100-150 stars is frequently called the ET Cluster but officially it is named NGC 457.  The name ET Cluster is comes from the idea that the stars of NGC 457 look a bit like the famous alien character from the movie E.T.  The human brain is well suited to finding familiar patterns in a seemingly random grouping of objects.  Much like people do with clouds or blots of paint people see all kinds of patterns in the stars which of course is the theme of this month’s night sky update.  Other names given to NGC 457 are Caldwell 13 (catalog number), the Owl Cluster and the Number 5 is Alive Cluster.

The ET Cluster is located in the constellation Cassiopeia near the bright star Delta Cassiopeiae.  This 21 million year old cluster of stars is situated about 10 thousand light years away in the Perseus Arm of the Milky Way Galaxy.  When you look at it through binoculars you will see a dim patch of light with about 20 or 30 stars visible.  With telescopes you can see around 100 stars that at even such a great distance will seem detached from the background stars.  Once you are looking at the ET Cluster you will notice two bright stars called Psi-1 and Psi-2 Cassiopeiae.  These two stars represent the eyes of ET which may not be in the cluster itself.  Below the eyes there is a long chain of stars that represents ET’s arms and below that is the main body of the cluster which is seen as ET’s body. 

To find the ET cluster first find the W-shape of the constellation Cassiopeia.  The bright “W” asterism of Cassiopeia will be visible high in the northeast after sunset.  As the night progresses the “W” will pass overhead in the north and will be seen in the northwest before sunrise.  Once you can identify Cassiopeia locate the two western most stars of the W-shape called Epsilon and Delta Cassiopeiae.  Then follow a line from Epsilon to Delta and continue for another 2.5 degrees below Delta and you will find the ET Cluster.   

http://www.iau.org/static/public/constellations/gif/CAS.gif

Any way you look at the ET cluster it stands out as one of the best in Cassiopeia and it sits in a crowed part of the sky in regards to other open star clusters.  If you can find the ET Cluster there are a number of open clusters within a 5 degree distance to the north.  A few of them are M103, NGC 663, NGC 654, NGC 659, NGC 436 and NGC 381.  From a dark location most of these are excellent binocular targets.        

The asterism for the week of October 20 is Kemble’s Cascade.  This is currently my favorite asterism and is one that we covered in April when talking about the constellation Camelopardalis.  I choose to return to this object for a few reasons.  First it is beautiful, second it is one of those objects that favor binoculars over telescopes and third the part of the sky it is in is loaded with lots of great objects in other constellations.  It is because of this last reason that part of the fun in observing Kemble’s cascade is in the search for it. 

This grouping of stars was discovered by an amateur astronomer named Lucian Kemble.  He was scanning Camelopardalis and noticed a string of stars that spanned about 2.5 degrees of sky.  It was later named in his honor and remains a popular target in the sparse constellation of Camelopardalis.

Kemble’s Cascade is a string of 20 stars, mostly 7th to 10th magnitude, which spans about 2.5 degrees.  The center of the string is accented with a 5th magnitude star.  The stars that make up Kemble’s Cascade are not related to each so what we see is just a chance alignment.  Following this cascade of stars to the southwest will bring us to an open star cluster called NGC 1502.  This cluster contains about 45 stars that will appear as a faint glow at the end of Kemble’s Cascade. 

One way to find Kemble’s Cascade is by first locating Beta and Alpha Cam using binoculars.  This can be done by first following the steps to find last week’s ET cluster.  The two bright stars in Cassiopeia, Delta and Epsilon Cassiopeiae will also help you find Kemble’s cascade. 

http://iau.org/static/public/constellations/gif/CAS.gif

Scan from Delta to Epsilon Cassiopeiae about 10 degrees to the northwest.  This will bring you to Gamma Cam.  Below Gamma Cam you will find Alpha and Beta Cam

http://iau.org/static/public/constellations/gif/CAM.gif

From Alpha Cam scan about 5 degrees to the east and you will find Kemble’s Cascade.

My favorite way to find Kemble’s Cascade is to first find the constellation Perseus south of the western half of the constellation Cassiopeia.

http://iau.org/static/public/constellations/gif/CAS.gif

http://iau.org/static/public/constellations/gif/PER.gif

With binoculars locate the bright star Mirfak at the center of Perseus.  This bright star is in the middle of the Alpha Persei Moving group of stars.  It is a nearby broad open star cluster that is beautiful in low power binoculars.  From here move north the helmet of Perseus to find NGC 869/884 also known as the Perseus Double Cluster.  Two degrees to the north you can find Stock 2 also known as the muscle man cluster.  A bit north and west from Stock 2 is the Heart and Soul nebulas and a scattering of dimmer open star clusters.  The Heart and Souls Nebulas are two beautiful emission nebulae that will require dark skies to be seen.  And finally another five degrees to the west you will find Kemble’s Cascade.  Now I admit that this method of finding Kemble’s Cascade seems a bit complicated and will require a more advanced map to identify all the objects just named, but it is not often you can star hop using deep sky objects instead stars.     

If you are up for a challenge and have dark skies there are even a few dim galaxies you can try to find that are north and west of Kemble’s Cascade called IC 342 and IC 356.  Unfortunately for these you will need large binoculars or a telescope to seem them. 

The final asterism we will cover is called the Coat Hanger asterism.  This group of stars was once believed to be a star cluster and was named Collinder 399.  After results from the Hipparcos satellite were analyzed it became clear that this grouping of stars was just a chance alignment.  It consists of ten stars with six in a line and four forming the hook of the hanger.  The member stars have distances ranging from 200 to a bit over 1000 light years. 

To find the Coat Hanger asterism we have to return the first asterism covered this month, the Summer Triangle.  The Coat Hanger is located near the eastern edge of the minor constellation Vulpecula the Fox.  Unfortunately Vulpecula is not the brightest of constellations so we will use the bright Summer Triangle stars Altair and Vega to locate the Coat Hanger.  Using binoculars scan between the bright stars Altair and Vega.  About 1/3 the distance between them is where you will find the Coat Hanger.  The Coat Hanger will appear upside down.

http://iau.org/static/public/constellations/gif/VUL.gif

Due to the amount of sky covered by the asterism binoculars may be the preferred way to see the Coat Hanger.  If you chose a telescope make sure to use low power eyepieces when observing this pattern of stars.  Other Objects in the vicinity of this asterism are the planetary nebulae M27 and M57, M11 the Wild Duck Cluster and the globular cluster M71.    

Our next Star Party will be held on Friday, November 7, 2014, from dusk until 10 p.m.

Weather permitting, the St. Louis Astronomical Society and the Science Center will set up a number of telescopes outdoors and be on-hand to answer your questions.  Telescope viewing begins at 8:00 p.m.  Regardless of the weather on November 7, join us indoors in our planetarium theater for “The Sky Tonight”.  Showtime is at 7 p.m.
This free, indoor star program will introduce you to the current night sky, the planets, and the seasonal constellations. Doors open 15 minutes before show time. Shows begins at 7 p.m. Sorry, no late admissions due to safety issues in the darkened theater.

The St. Louis Astronomical Society hosts the monthly Star Parties at the Science Center which are held on the first Friday of each month. Our Monthly Star Parties are open to the public and free of charge.  For more information about the St. Louis Astronomical Society visit their website at www.slasonline.org

Week of Monday, October 20

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, October 20.  All times are given as local St. Louis time (Central Daylight Time).  For definitions of terminology used in the night sky update, click the highlighted text.

Information updated weekly or as needed.

Join us for our next star party, Friday, November 7, 2014 held in association with the St. Louis Astronomical Society. For details, see the information at the bottom of this page.

The Sun and the Moon

Sunrise is at 7:15 a.m. on Monday, October 20 and sunset is at 6:16 p.m. providing us with 11 hours of daylight.  Even after sunset, the light from the Sun will still dimly illuminate our sky for about 1.5 hours.  This period of time is called twilight, which ends around 7:44 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 12:46 p.m. this week.  Below you will find sunrise and sunset times for the rest of the week.

Day

Sunrise

Sunset

20 Oct

7:15 a.m.

6:16 p.m.

21 Oct

7:16 a.m.

6:14 p.m.

22 Oct

7:17 a.m.

6:13 p.m.

23 Oct

7:18 a.m.

6:12 p.m.

24 Oct

7:19 a.m.

6:11 p.m.

25 Oct

7:20 a.m.

6:09 p.m.

26 Oct

7:21 a.m.

6:08 p.m.

 

On October 23 the Moon will pass between the Earth and Sun.  This happens once a month during new moon but when they are aligned just right we see the Moon pass in front of the Sun or what is called a solar eclipse.  The October 23 solar eclipse will only be a partial eclipse but it will still be interesting to see.  The eclipse starts for us in St. Louis around 4:41 p.m.  As the Moon gradually moves in front of the Sun you will see a dark disk obscure it.  By 5:47 p.m. which is the greatest extent of the eclipse you will only see about 36% of the Sun covered by the Moon.  If you have a safe means to observe the eclipse you just need to find a high point nearby with a clear view of the west.  If you do not have a safe way to observe the Sun you can tune in to live.slooh.com where they will broadcast the eclipse live.  The eclipse will still be in progress as the sun sets on St. Louis. 

***************************************************************************************************************

Unfortunately solar eclipse can only be safely observed if you have safe solar filters or some kind of projection device.  You should NEVER look directly at the Sun through an unfiltered telescope, binocular, camera or without solar filter glasses. 

Below you will find links that have information about the October 23 partial eclipse, how you can safely observe solar eclipse and why looking at the Sun will cause serious eye damage that could lead to loss of vision.  I would highly recommend reading the eye damage link. 

http://eclipse.gsfc.nasa.gov/OH/OHfigures/OH2014-Fig04.pdf

http://www.mreclipse.com/Totality2/TotalityCh11.html#Pinhole

http://www.mreclipse.com/Special/filters.html       

Moonrise for Monday, October 20 occurs at 4:05 a.m. and moonset will occur at 4:36 p.m.  On Monday, October 20 the Moon will be exhibiting a waning crescent phase with about 10% of the lunar disk illuminated.  New moon occurs on October 23 at 4:57 p.m.

International Space Station (ISS) Observing

Visible passes of ISS from St. Louis this week occur during the evening hours.  The best of these is on the evenings of October 25 and 26. 

Catch ISS flying over St. Louis in the evening hours starting Monday, October 20. 

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

20 Oct

-0.6

20:18:14

10

NNW

20:19:00

14

NNW

20:19:00

14

NNW

21 Oct

-1.3

19:29:30

10

NNW

19:31:48

17

NNE

19:31:59

17

NNE

22 Oct

-1.0

18:40:49

10

NNW

18:42:30

13

NNE

18:44:11

10

NE

22 Oct

-1.0

20:16:32

10

NW

20:17:53

22

NW

20:17:53

22

NW

23 Oct

-2.4

19:27:36

10

NW

19:30:39

32

NNE

19:30:58

31

NE

24 Oct

-1.7

18:38:42

10

NNW

18:41:23

22

NNE

18:44:03

10

E

24 Oct

-1.4

20:15:00

10

WNW

20:17:02

31

W

20:17:02

31

W

25 Oct

-3.4

19:25:47

10

NW

19:29:08

85

NE

19:30:20

37

SE

26 Oct

-2.9

18:36:40

10

NW

18:39:55

46

NE

18:43:08

10

ESE

26 Oct

-0.7

20:14:05

10

W

20:16:20

17

SW

20:16:43

17

SW

27 Oct

-1.5

19:24:16

10

WNW

19:27:15

31

SW

19:30:13

10

SSE

 

Magnitude (Mag): The Measure of brightness for a celestial object.  The lower the value is, the brighter the object will be.

Altitude (Alt):  The angle of a celestial object measured upwards from the observer’s horizon.

Azimuth (Az):  The direction of a celestial object, measured clockwise from an observer’s location with north being 0°, east being 90°, south being 180° and west being 270°. 

For information about ISS flyovers and other visible satellites, visit www.heavens-above.com

Detailed information regarding all unmanned exploration of our universe, missions past, present, and planned, can be found at Jet Propulsion Laboratories:

http://www.jpl.nasa.gov/

The Planets Visible Without A Telescope

Mars

Mars is now in the constellation Ophiuchus and rises before the Sun sets.  Mars will be seen in the southwestern skies about 20 minutes after sunset.  Mars will set by 9:18 p.m. 

Jupiter

The largest planet in the solar system is visible once again in the morning skies.  Jupiter can be found rising by 1:39 a.m. and will be easily visible by 2:10  a.m.        

Uranus and Neptune Opposition 2014

The two most distant planets in our solar system will be at their best for the next couple of months.  Neptune has already reached opposition and Uranus will reach opposition on October 7, 2014.  The opposition of a planet is when it is in opposition with the Sun.  What that means is a planet or other body such as an asteroid is seen on the opposite side of the Earth than the Sun is.  From our perspective this is when an object is at its brightest and also coincides with the object’s closest approach to the Earth.  Only objects further from the Sun than we are can be in opposition. 

Of the two planets Uranus will be the brightest.  Uranus is already appearing as a 5.8 magnitude object and will continue to brighten until October 7.  Uranus is normally a planet that requires binoculars to be seen but when the planet is nearing opposition dark sky observers can see it with the unaided eye.  Through telescopes observers will resolve Uranus into a small disk shaped object that may display a slight greenish blue color.  Large telescopes using high magnifications up to 300x might be able to discern dark and light patches called albedo features.  These features require large aperture telescopes and better than average viewing conditions to be seen. 

Uranus is currently in the constellation Pisces.  Pisces is very difficult to see in light polluted skies so it is better to start with the Great Square of Autumn.  This asterism connects the constellations Andromeda and Pegasus all of which will be seen high in the eastern sky by 10:00 p.m.  As the Great Square sits high in the east if you follow a line connecting the stars Scheat (Beta Peg) through Algenib (Gamma Peg) about the same distance that lays between the two stars you will find three stars the stand next to one another in a straight line.  The brightest of these stars is Delta Piscium.  Uranus is about four degrees south of these stars.  You will need either a desktop planetarium program or detailed star chart to help you pinpoint which star like object is Uranus. 

http://www.iau.org/static/public/constellations/gif/PSC.gif

http://www.iau.org/static/public/constellations/gif/PEG.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Neptune reached opposition on August 29, 2014.  It is now at its peak brightness of 7.8 magnitude.  This means that you will need at least binoculars to see this distant planet even when it is at its brightest.  Through binoculars Neptune will appear as a dim star like object in the constellation Aquarius.  To find Neptune first locate the bright star Fomalhaut.  About 6 to 10 degrees north of Fomalhaut you will find six bright stars that are shaped like a hyperboloid.  Scanning the sky further north you will find the star Sigma Aquarii.  Neptune will be just east of this star.      

Using a telescope most will see a star like object that when magnified enough will reveal a greyish blue disk.  Using a large telescope and high magnification up to 300x it may be possible to detect albedo features and Neptune largest moon Triton.  Triton will appear as a dim star right next to Neptune.

Like Uranus Neptune will require some kind of astronomy software of a detailed map to find.  As we pass by these planets in our orbit see if you can detect there shift amongst the background stars.  Below are a few links that will be helpful in locating Neptune and the stars mentioned above.

http://www.iau.org/static/public/constellations/gif/AQR.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Constellation of the Month

Each month we will highlight one constellation and some of the objects that can be found within the boundaries of that constellation.  At the start of the month we will list only a few of these objects and each week we will add another to the list.  Some objects will be visible to the unaided eye and some may require a telescope.  Many of the objects listed will require a map of the sky to find or may require repeat observations to notice various properties.  Links to star charts and other information that will be useful in identifying the objects listed will be given at the end of each week’s section. 

This month we will once again forego a single constellation and discuss a number of different patterns.  This month we will work on finding some of the informal groupings of stars called asterisms.  These informal patterns can be large groups that contain multiple constellations or they can be small dim groupings that require a telescope to see. Many of them serve as useful markers in the sky that help you find dimmer and more difficult objects.  

The first asterism we will cover in October is the Summer Triangle.  This is one we have mentioned and used numerous times in the night sky update.  Last week in fact we used it in reference to finding Cygnus the Swan.  Other constellations that comprise this asterism are Lyra the Harp and Aquila the Eagle.  Inside the Summer Triangle we find the constellations Vulpecula the Fox, Sagitta the Arrow and just outside the eastern edge is Delphinus the Dolphin.  Scattered throughout these constellations are many gems for double star observers, numerous open star clusters and a number of nebulas.  The first step in finding all of these is taken by first locating the Summer Triangle.

Also of interest regarding the Summer Triangle is a Mission called Kepler.  This is a space telescope that steadily observed the patch of sky between Cygnus and Lyra.  What Kepler was looking for was the subtle changes in a star’s light due to the effects of a planet orbiting around it.  Thanks to the Kepler mission and other research programs scientists currently have 5,022 candidate exoplanets (planets orbiting other stars) of which 1,746 have been confirmed.  With these numbers scientists have estimated that there are likely as many planets as there are stars in the Milky Way galaxy if not more.  If you would like to learn more about Kepler and the hunt for exoplanets visit http://planetquest.jpl.nasa.gov/   

With a name like the Summer Triangle you would think that we would start losing this asterism soon as we approach winter.  Due to the longer nights we will continue to see the Summer Triangle for the rest of the year.  Tonight go outside and simply look straight up and you should see the three bright stars Deneb, Vega and Altair that define the triangle shape.  Once you can find this asterism grab some binocular and a reclined chair and just start scanning this part of the sky.  Dense star fields and numerous stars clusters will keep you busy for some time. 

The asterism we will cover for the week of October 6 is the Great Square of Autumn.  This is another asterism that can serve as a reference point or guide post in the sky.  Much like the Summer Triangle, the Great Square of Autumn can be used to find a number of constellations and other objects of interest.  The Great Square primarily consists of two constellations; Andromeda and Pegasus.  As most of the square is in Pegasus it is also called the Square of Pegasus.  The Great Square of Autumn can also help you find the constellations Piscis, Cetus, Aquarius, Lacerta and Equuleus. 

One of the more challenging objects the Great Square can help you find is the bright variable star Mira.  Mira is a long period variable that every 333 days or so will brighten from 10th magnitude up to about 3rd magnitude.  This change does not occur in one day but over the entire 333 day cycle.  The brightening of the Mira takes about 100 days and will take twice as long to fade back to minima.  Mira was one of the first variable stars other than bright supernovas or novae to be discovered and it certainly is one of the brightest.  Unfortunately Mira has already peaked in brightness and is already well into its slow downward fade for 2014. 

Mira is an M-class red giant star that is approximately 6 billion years old.  The variable nature of Mira is due to an internal pulsation which is a result of the unstable nature of the star.  The Sun will likely come to a similar state as it evolves into a red giant star in another 5 billion years.  Mira is one of the brightest stars in the constellation Cetus.  Depending on the map you use to find Mira you may find it labeled Omicron Ceti.  

http://www.iau.org/static/public/constellations/gif/CET.gif

Finding the Great Square of Autumn is simple but it does depend on what time you look for it.  After sunset the square will be seen low in the east looking more like a diamond.  At midnight it will be nearly overhead and before sunrise it will be found low in the west. 

For the rest of the month we will cover asterisms that are still helpful guides in the sky but they will be found in individual constellations and will require an optical device such as binoculars to see.

The asterism for the week of October 13 is the star cluster known as the ET cluster.  This group of roughly 100-150 stars is frequently called the ET Cluster but officially it is named NGC 457.  The name ET Cluster is comes from the idea that the stars of NGC 457 look a bit like the famous alien character from the movie E.T.  The human brain is well suited to finding familiar patterns in a seemingly random grouping of objects.  Much like people do with clouds or blots of paint people see all kinds of patterns in the stars which of course is the theme of this month’s night sky update.  Other names given to NGC 457 are Caldwell 13 (catalog number), the Owl Cluster and the Number 5 is Alive Cluster.

The ET Cluster is located in the constellation Cassiopeia near the bright star Delta Cassiopeiae.  This 21 million year old cluster of stars is situated about 10 thousand light years away in the Perseus Arm of the Milky Way Galaxy.  When you look at it through binoculars you will see a dim patch of light with about 20 or 30 stars visible.  With telescopes you can see around 100 stars that at even such a great distance will seem detached from the background stars.  Once you are looking at the ET Cluster you will notice two bright stars called Psi-1 and Psi-2 Cassiopeiae.  These two stars represent the eyes of ET which may not be in the cluster itself.  Below the eyes there is a long chain of stars that represents ET’s arms and below that is the main body of the cluster which is seen as ET’s body. 

To find the ET cluster first find the W-shape of the constellation Cassiopeia.  The bright “W” asterism of Cassiopeia will be visible high in the northeast after sunset.  As the night progresses the “W” will pass overhead in the north and will be seen in the northwest before sunrise.  Once you can identify Cassiopeia locate the two western most stars of the W-shape called Epsilon and Delta Cassiopeiae.  Then follow a line from Epsilon to Delta and continue for another 2.5 degrees below Delta and you will find the ET Cluster.   

http://www.iau.org/static/public/constellations/gif/CAS.gif

Any you look at the ET cluster it stands out as one of the best in Cassiopeia and it sits in a crowed part of the sky in regards to other open star clusters.  If you can find the ET Cluster there are a number of open clusters within a 5 degree distance to the north.  A few of them are M103, NGC 663, NGC 654, NGC 659, NGC 436 and NGC 381.  From a dark location most of these are excellent binocular targets.        

The asterism for the week of October 20 is Kemble’s Cascade.  This is currently my favorite asterism and is one that we covered in April when talking about the constellation Camelopardalis.  I choose to return to this object for a few reasons.  First it is beautiful, second it is one of those objects that favor binoculars over telescopes and third the part of the sky it is in is loaded with lots of great objects in other constellations.  It is because of this last reason that part of the fun in observing Kemble’s cascade is in the search for it. 

This grouping of stars was discovered by an amateur astronomer named Lucian Kemble.  He was scanning Camelopardalis and noticed a string of stars that spanned about 2.5 degrees of sky.  It was later named in his honor and remains a popular target in the sparse constellation of Camelopardalis.

Kemble’s Cascade is a string of 20 stars, mostly 7th to 10th magnitude, which spans about 2.5 degrees.  The center of the string is accented with a 5th magnitude star.  The stars that make up Kemble’s Cascade are not related to each so what we see is just a chance alignment.  Following this cascade of stars to the southwest will bring us to an open star cluster called NGC 1502.  This cluster contains about 45 stars that will appear as a faint glow at the end of Kemble’s Cascade. 

One way to find Kemble’s Cascade is by first locating Beta and Alpha Cam using binoculars.  This can be done by first following the steps to find last week’s ET cluster.  The two bright stars in Cassiopeia, Delta and Epsilon Cassiopeiae will also help you find Kemble’s cascade. 

http://iau.org/static/public/constellations/gif/CAS.gif

Scan from Delta to Epsilon Cassiopeiae about 10 degrees to the northwest.  This will bring you to Gamma Cam.  Below Gamma Cam you will find Alpha and Beta Cam

http://iau.org/static/public/constellations/gif/CAM.gif

From Alpha Cam scan about 5 degrees to the east and you will find Kemble’s Cascade.

My favorite way to find Kemble’s Cascade is to first find the constellation Perseus south of the western half of the constellation Cassiopeia.

http://iau.org/static/public/constellations/gif/CAS.gif

http://iau.org/static/public/constellations/gif/PER.gif

With binoculars locate the bright star Mirfak at the center of Perseus.  This bright star is in the middle of the Alpha Persei Moving group of stars.  It is a nearby broad open star cluster that is beautiful in low power binoculars.  From here move north the helmet of Perseus to find NGC 869/884 also known as the Perseus Double Cluster.  Two degrees to the north you can find Stock 2 also known as the muscle man cluster.  A bit north and west from Stock 2 is the Heart and Soul nebulas and a scattering of dimmer open star clusters.  The Heart and Souls Nebulas are two beautiful emission nebulae that will require dark skies to be seen.  And finally another five degrees to the west you will find Kemble’s Cascade.  Now I admit that this method of finding Kemble’s Cascade seems a bit complicated and will require a more advanced map to identify all the objects just named, but it is not often you can star hop using deep sky objects instead stars.     

If you are up for a challenge and have dark skies there are even a few dim galaxies you can try to find that are north and west of Kemble’s Cascade called IC 342 and IC 356.  Unfortunately for these you will need large binoculars or a telescope to seem them. 

Our next Star Party will be held on Friday, November 7, 2014, from dusk until 10 p.m.

Weather permitting, the St. Louis Astronomical Society and the Science Center will set up a number of telescopes outdoors and be on-hand to answer your questions.  Telescope viewing begins at 8:00 p.m.  Regardless of the weather on November 7, join us indoors in our planetarium theater for “The Sky Tonight”.  Showtime is at 7 p.m.
This free, indoor star program will introduce you to the current night sky, the planets, and the seasonal constellations. Doors open 15 minutes before show time. Shows begins at 7 p.m. Sorry, no late admissions due to safety issues in the darkened theater.

The St. Louis Astronomical Society hosts the monthly Star Parties at the Science Center which are held on the first Friday of each month. Our Monthly Star Parties are open to the public and free of charge.  For more information about the St. Louis Astronomical Society visit their website at www.slasonline.org

Week of Monday, October 13

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, October 13.  All times are given as local St. Louis time (Central Daylight Time).  For definitions of terminology used in the night sky update, click the highlighted text.

Information updated weekly or as needed.

Join us for our next star party, Friday, November 7, 2014 held in association with the St. Louis Astronomical Society. For details, see the information at the bottom of this page.

The Sun and the Moon

Sunrise is at 7:08 a.m. on Monday, October 13 and sunset is at 6:26 p.m. providing us with about 11.5 hours of daylight.  Even after sunset, the light from the Sun will still dimly illuminate our sky for about 1.5 hours.  This period of time is called twilight, which ends around 7:54 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 12:47 p.m. this week.

On October 23 the Moon will pass between the Earth and Sun.  This happens once a month during new moon but when they are aligned just right we see the Moon pass in front of the Sun or what is called a solar eclipse.  The October 23 solar eclipse will only be a partial eclipse but it will still be interesting to see.  The eclipse starts for us in St. Louis around 4:41 p.m.  As the Moon gradually moves in front of the Sun you will see a dark disk obscure it.  By 5:47 p.m. which is the greatest extent of the eclipse you will only see about 36% of the Sun covered by the Moon.  If you have a safe means to observe the eclipse you just need to find a high point nearby with a clear view of the west.  If you do not have a safe way to observe the Sun you can tune in to live.slooh.com where they will broadcast the eclipse live.  The eclipse will still be in progress as the sun sets on St. Louis. 

***************************************************************************************************************

Unfortunately solar eclipse can only be safely observed if you have safe solar filters or some kind of projection device.  You should NEVER look directly at the Sun through an unfiltered telescope, binocular, camera or without solar filter glasses. 

Below you will find links that have information about the October 23 partial eclipse, how you can safely observe solar eclipse and why looking at the Sun will cause serious eye damage that could lead to loss of vision.  I would highly recommend reading the eye damage link. 

http://eclipse.gsfc.nasa.gov/OH/OHfigures/OH2014-Fig04.pdf

http://www.mreclipse.com/Totality2/TotalityCh11.html#Pinhole

http://www.mreclipse.com/Special/filters.html       

Moonrise for Monday, October 13 occurs at 10:39 p.m. and moonset will occur at 1:08 p.m. on the following day.  On Monday, October 13 the Moon will be exhibiting a waning gibbous phase with about 70% of the lunar disk illuminated.  Last quarter moon occurs on October 15 at 2:31 p.m.

International Space Station (ISS) Observing

Visible passes of ISS from St. Louis this week occur during the evening hours.  The best of these is on the evening of October 20.  Next week will be better for ISS passes as the few passes this week do not achieve and altitude above 15 degrees. 

Catch ISS flying over St. Louis in the evening hours starting Monday, October 13. 

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

13 Oct

-0.6

19:32:20

10

NW

19:33:56

13

NNW

19:35:32

10

NNE

18 Oct

-0.3

20:20:00

10

NNW

20:20:10

11

NNW

20:20:10

11

NNW

19 Oct

-0.8

19:31:32

10

N

19:32:37

11

NNE

19:33:08

11

NNE

20 Oct

-0.6

20:18:14

10

NNW

20:18:59

14

NNW

20:18:59

14

NNW

Magnitude (Mag): The Measure of brightness for a celestial object.  The lower the value is, the brighter the object will be.

Altitude (Alt):  The angle of a celestial object measured upwards from the observer’s horizon.

Azimuth (Az):  The direction of a celestial object, measured clockwise from an observer’s location with north being 0°, east being 90°, south being 180° and west being 270°.

For information about ISS flyovers and other visible satellites, visit www.heavens-above.com

Detailed information regarding all unmanned exploration of our universe, missions past, present, and planned, can be found at Jet Propulsion Laboratories:

http://www.jpl.nasa.gov/

The Planets Visible Without A Telescope

Mars

Mars is now in the constellation Ophiuchus and rises before the Sun sets.  Mars can be seen with Saturn in the southwestern skies about 20 minutes after sunset.  Mars will set by 9:25 p.m. 

Jupiter

The largest planet in the solar system is visible once again in the morning skies.  Jupiter can be found rising by 2:05 a.m. and will be easily visible by 2:40 a.m.    

Saturn

Saturn will be visible about 20 minutes after sunset.  Saturn will remain with us until 7:59 p.m.  Saturn can be found near the bright double star Zubenelgenubi.  Take a look at Saturn soon as we will lose the planet to glare of the Sun in another week or so.       

Uranus and Neptune Opposition 2014

The two most distant planets in our solar system will be at their best for the next couple of months.  Neptune has already reached opposition and Uranus will reach opposition on October 7, 2014.  The opposition of a planet is when it is in opposition with the Sun.  What that means is a planet or other body such as an asteroid is seen on the opposite side of the Earth than the Sun is.  From our perspective this is when an object is at its brightest and also coincides with the object’s closest approach to the Earth.  Only objects further from the Sun than we are can be in opposition. 

Of the two planets Uranus will be the brightest.  Uranus is already appearing as a 5.8 magnitude object and will continue to brighten until October 7.  Uranus is normally a planet that requires binoculars to be seen but when the planet is nearing opposition dark sky observers can see it with the unaided eye.  Through telescopes observers will resolve Uranus into a small disk shaped object that may display a slight greenish blue color.  Large telescopes using high magnifications up to 300x might be able to discern dark and light patches called albedo features.  These features require large aperture telescopes and better than average viewing conditions to be seen. 

Uranus is currently in the constellation Pisces.  Pisces is very difficult to see in light polluted skies so it is better to start with the Great Square of Autumn.  This asterism connects the constellations Andromeda and Pegasus all of which will be seen high in the eastern sky by 10:00 p.m.  As the Great Square sits high in the east if you follow a line connecting the stars Scheat (Beta Peg) through Algenib (Gamma Peg) about the same distance that lays between the two stars you will find three stars the stand next to one another in a straight line.  The brightest of these stars is Delta Piscium.  Uranus is about four degrees south of these stars.  You will need either a desktop planetarium program or detailed star chart to help you pinpoint which star like object is Uranus. 

http://www.iau.org/static/public/constellations/gif/PSC.gif

http://www.iau.org/static/public/constellations/gif/PEG.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Neptune reached opposition on August 29, 2014.  It is now at its peak brightness of 7.8 magnitude.  This means that you will need at least binoculars to see this distant planet even when it is at its brightest.  Through binoculars Neptune will appear as a dim star like object in the constellation Aquarius.  To find Neptune first locate the bright star Fomalhaut.  About 6 to 10 degrees north of Fomalhaut you will find six bright stars that are shaped like a hyperboloid.  Scanning the sky further north you will find the star Sigma Aquarii.  Neptune will be just east of this star.      

Using a telescope most will see a star like object that when magnified enough will reveal a greyish blue disk.  Using a large telescope and high magnification up to 300x it may be possible to detect albedo features and Neptune largest moon Triton.  Triton will appear as a dim star right next to Neptune.

Like Uranus Neptune will require some kind of astronomy software of a detailed map to find.  As we pass by these planets in our orbit see if you can detect there shift amongst the background stars.  Below are a few links that will be helpful in locating Neptune and the stars mentioned above.

http://www.iau.org/static/public/constellations/gif/AQR.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Constellation of the Month

Each month we will highlight one constellation and some of the objects that can be found within the boundaries of that constellation.  At the start of the month we will list only a few of these objects and each week we will add another to the list.  Some objects will be visible to the unaided eye and some may require a telescope.  Many of the objects listed will require a map of the sky to find or may require repeat observations to notice various properties.  Links to star charts and other information that will be useful in identifying the objects listed will be given at the end of each week’s section. 

This month we will once again forego a single constellation and discuss a number of different patterns.  This month we will work on finding some of the informal groupings of stars called asterisms.  These informal patterns can be large groups that contain multiple constellations or they can be small dim groupings that require a telescope to see. Many of them serve as useful markers in the sky that help you find dimmer and more difficult objects.  

The first asterism we will cover in October is the Summer Triangle.  This is one we have mentioned and used numerous times in the night sky update.  Last week in fact we used it in reference to finding Cygnus the Swan.  Other constellations that comprise this asterism are Lyra the Harp and Aquila the Eagle.  Inside the Summer Triangle we find the constellations Vulpecula the Fox, Sagitta the Arrow and just outside the eastern edge is Delphinus the Dolphin.  Scattered throughout these constellations are many gems for double star observers, numerous open star clusters and a number of nebulas.  The first step in finding all of these is taken by first locating the Summer Triangle.

Also of interest regarding the Summer Triangle is a Mission called Kepler.  This is a space telescope that steadily observed the patch of sky between Cygnus and Lyra.  What Kepler was looking for was the subtle changes in a star’s light due to the effects of a planet orbiting around it.  Thanks to the Kepler mission and other research programs scientists currently have 5,022 candidate exoplanets (planets orbiting other stars) of which 1,746 have been confirmed.  With these numbers scientists have estimated that there are likely as many planets as there are stars in the Milky Way galaxy if not more.  If you would like to learn more about Kepler and the hunt for exoplanets visit http://planetquest.jpl.nasa.gov/ 

With a name like the Summer Triangle you would think that we would start losing this asterism soon as we approach winter.  Due to the longer nights we will continue to see the Summer Triangle for the rest of the year.  Tonight go outside and simply look straight up and you should see the three bright stars Deneb, Vega and Altair that define the triangle shape.  Once you can find this asterism grab some binocular and a reclined chair and just start scanning this part of the sky.  Dense star fields and numerous stars clusters will keep you busy for some time. 

The asterism we will cover for the week of October 6 is the Great Square of Autumn.  This is another asterism that can serve as a reference point or guide post in the sky.  Much like the Summer Triangle, the Great Square of Autumn can be used to find a number of constellations and other objects of interest.  The Great Square primarily consists of two constellations; Andromeda and Pegasus.  As most of the square is in Pegasus it is also called the Square of Pegasus.  The Great Square of Autumn can also help you find the constellations Piscis, Cetus, Aquarius, Lacerta and Equuleus. 

One of the more challenging objects the Great Square can help you find is the bright variable star Mira.  Mira is a long period variable that every 333 days or so will brighten from 10th magnitude up to about 3rd magnitude.  This change does not occur in one day but over the entire 333 day cycle.  The brightening of the Mira takes about 100 days and will take twice as long to fade back to minima.  Mira was one of the first variable stars other than bright supernovas or novae to be discovered and it certainly is one of the brightest.  Unfortunately Mira has already peaked in brightness and is already well into its slow downward fade for 2014. 

Mira is an M-class red giant star that is approximately 6 billion years old.  The variable nature of Mira is due to an internal pulsation which is a result of the unstable nature of the star.  The Sun will likely come to a similar state as it evolves into a red giant star in another 5 billion years.  Mira is one of the brightest stars in the constellation Cetus.  Depending on the map you use to find Mira you may find it labeled Omicron Ceti.  

http://www.iau.org/static/public/constellations/gif/CET.gif

Finding the Great Square of Autumn is simple but it does depend on what time you look for it.  After sunset the square will be seen low in the east looking more like a diamond.  At midnight it will be nearly overhead and before sunrise it will be found low in the west. 

For the rest of the month we will cover asterisms that are still helpful guides in the sky but they will be found in individual constellations and will require an optical device such as binoculars to see.

The asterism for the week of October 13 is the star cluster known as the ET cluster.  This group of roughly 100-150 stars is frequently called the ET Cluster but officially it is named NGC 457.  The name ET Cluster is comes from the idea that the stars of NGC 457 look a bit like the famous alien character from the movie E.T.  The human brain is well suited to finding familiar patterns in a seemingly random grouping of objects.  Much like people do with clouds or blots of paint people see all kinds of patterns in the stars which of course is the theme of this month’s night sky update.  Other names given to NGC 457 are Caldwell 13 (catalog number), the Owl Cluster and the Number 5 is Alive Cluster.

The ET Cluster is located in the constellation Cassiopeia near the bright star Delta Cassiopeiae.  This 21 million year old cluster of stars is situated about 10 thousand light years away in the Perseus Arm of the Milky Way Galaxy.  When you look at it through binoculars you will see a dim patch of light with about 20 or 30 stars visible.  With telescopes you can see around 100 stars that at even such a great distance will seem detached from the background stars.  Once you are looking at the ET Cluster you will notice two bright stars called Psi-1 and Psi-2 Cassiopeiae.  These two stars represent the eyes of ET which may not be in the cluster itself.  Below the eyes there is a long chain of stars that represents ET’s arms and below that is the main body of the cluster which is seen as ET’s body. 

To find the ET cluster first find the W-shape of the constellation Cassiopeia.  The bright “W” asterism of Cassiopeia will be visible high in the northeast after sunset.  As the night progresses the “W” will pass overhead in the north and will be seen in the northwest before sunrise.  Once you can identify Cassiopeia locate the two western most stars of the W-shape called Epsilon and Delta Cassiopeiae.  Then follow a line from Epsilon to Delta and continue for another 2.5 degrees below Delta and you will find the ET Cluster.   

http://www.iau.org/static/public/constellations/gif/CAS.gif

Any you look at the ET cluster it stands out as one of the best in Cassiopeia and it sits in a crowed part of the sky in regards to other open star clusters.  If you can find the ET Cluster there are a number of open clusters within a 5 degree distance to the north.  A few of them are M103, NGC 663, NGC 654, NGC 659, NGC 436 and NGC 381.  From a dark location most of these are excellent binocular targets.   

Our next Star Party will be held on Friday, November 7, 2014, from dusk until 10 p.m.

Weather permitting, the St. Louis Astronomical Society and the Science Center will set up a number of telescopes outdoors and be on-hand to answer your questions.  Telescope viewing begins at 8:00 p.m.  Regardless of the weather on November 7, join us indoors in our planetarium theater for “The Sky Tonight”.  Showtime is at 7 p.m.
This free, indoor star program will introduce you to the current night sky, the planets, and the seasonal constellations. Doors open 15 minutes before show time. Shows begins at 7 p.m. Sorry, no late admissions due to safety issues in the darkened theater.

The St. Louis Astronomical Society hosts the monthly Star Parties at the Science Center which are held on the first Friday of each month. Our Monthly Star Parties are open to the public and free of charge.  For more information about the St. Louis Astronomical Society visit their website at www.slasonline.org

Week of Monday, October 6

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, October 6.  All times are given as local St. Louis time (Central Daylight Time).  For definitions of terminology used in the night sky update, click the highlighted text.

Information updated weekly or as needed.

Join us for our next star party, Friday, November 7, 2014 held in association with the St. Louis Astronomical Society. For details, see the information at the bottom of this page.

The Sun and the Moon

Sunrise is at 7:02 a.m. on Monday, October 6 and sunset is at 6:36 p.m. providing us with about 11.5 hours of daylight.  Even after sunset, the light from the Sun will still dimly illuminate our sky for about 1.5 hours.  This period of time is called twilight, which ends around 8:04 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 12:49 p.m. this week.

On October 23 the Moon will pass between the Earth and Sun.  This happens once a month during new moon but when they are aligned just right we see the Moon pass in front of the Sun or what is called a solar eclipse.  The October 23 solar eclipse will only be a partial eclipse but it will still be interesting to see.  The eclipse starts for us in St. Louis around 4:41 p.m.  As the Moon gradually moves in front of the Sun you will see a dark disk obscure it.  By 5:47 p.m. which is the greatest extent of the eclipse you will only see about 36% of the Sun covered by the Moon.  If you have a safe means to observe the eclipse you just need to find a high point nearby with a clear view of the west.  If you do not have a safe way to observe the Sun you can tune in to live.slooh.com where they will broadcast the eclipse live.  The eclipse will still be in progress as the sun sets on St. Louis. 

***************************************************************************************************************

Unfortunately solar eclipse can only be safely observed if you have safe solar filters or some kind of projection device.  You should NEVER look directly at the Sun through an unfiltered telescope, binocular, camera or without solar filter glasses. 

Below you will find links that have information about the October 23 partial eclipse, how you can safely observe solar eclipse and why looking at the Sun will cause serious eye damage that could lead to loss of vision.  I would highly recommend reading the eye damage link. 

http://eclipse.gsfc.nasa.gov/OH/OHfigures/OH2014-Fig04.pdf

http://www.mreclipse.com/Totality2/TotalityCh11.html#Pinhole

http://www.mreclipse.com/Special/filters.html     

Moonrise for Monday, October 6 occurs at 5:32 p.m. and moonset will occur at 6:01 a.m. on the following day.  On Monday, October 6 the Moon will be exhibiting a waxing gibbous phase with about 96% of the lunar disk illuminated.  Full moon occurs on October 8 at 5:51 p.m.

On Wednesday, October 8 the Moon will pass through the Earth’s shadow treating us to the second total lunar eclipse of 2014.  A lunar eclipse occurs when the Moon passes through the Earth’s shadow.  On October 8 the Moon will begin its slow trek through our shadow at 3:15 a.m.  At 4:14 a.m. it will begin to enter the darkest part of the Earth’s shadow and finally totality will start at 5:25 a.m. and end at 6:24 a.m.

Leading up to totality the Moon will gradually become darker until it is completely within the umbral portion of our shadow.  When this occurs the Moon will usually exhibit a reddish color.  The reason for the color change is that in the umbral portion of Earth’s shadow there is a little light that passes through our atmosphere.  Our atmosphere scatters shorter wavelengths of light but allows for the longer red wavelengths to filter through.  This dim red light is what illuminates the Moon during a total lunar eclipse.  Red is the typical color but coppery shades of yellow can also occur.  The color we see is dependent on how polluted the stratosphere is.  The typical pollutants that affect the Moon’s color are aerosols lofted high into the stratosphere by volcanic eruptions and forest fires. 

You will have to get up early to catch this eclipse but as no two are exactly alike it will be worth losing a few Z’s to catch one of nature’s most beautiful shows.  The same aerosols that affect the Moon’s color during an eclipse can also affect the colors we see during sunrise.  If any ash clouds are over your viewing location sunsets and sunrises can display very vivid purple, pink and orange colors giving the horizon a fiery appearance.  So perhaps while enjoying October’s total lunar eclipse we may also enjoy a beautiful volcanic sunrise.  Below you will find maps and additional information regarding this total lunar eclipse.

http://eclipse.gsfc.nasa.gov/OH/OHfigures/OH2014-Fig03.pdf

http://www.skyandtelescope.com/astronomy-news/observing-news/total-lunar-eclipse-09262014/

International Space Station (ISS) Observing

Visible passes of ISS from St. Louis this week occur during the evening hours.  The best of these are on the evenings of October 7 and 9.  To learn more about these passes and others follow the links below.

Catch ISS flying over St. Louis in the evening hours starting Monday, October 6. 

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

06 Oct

-2.8

20:21:35

10

WSW

20:24:27

59

W

20:24:27

59

W

07 Oct

-3.3

19:32:21

10

SW

19:35:37

61

SE

19:37:40

21

ENE

08 Oct

-1.6

20:20:08

10

W

20:23:04

28

NNW

20:23:35

27

NNW

09 Oct

-2.3

19:30:25

10

WSW

19:33:37

46

NW

19:36:29

12

NE

10 Oct

-0.8

20:19:12

10

WNW

20:21:19

16

NNW

20:22:05

15

N

11 Oct

-1.1

19:26:03

10

W

19:31:42

21

NNW

19:34:21

10

NNE

12 Oct

-0.4

20:18:48

10

NNW

20:19:36

11

NNW

20:20:06

10

N

13 Oct

-0.6

19:28:11

10

NW

19:29:50

13

NNW

19:31:30

10

NNE

Magnitude (Mag): The Measure of brightness for a celestial object.  The lower the value is, the brighter the object will be.

Altitude (Alt):  The angle of a celestial object measured upwards from the observer’s horizon.

Azimuth (Az):  The direction of a celestial object, measured clockwise from an observer’s location with north being 0°, east being 90°, south being 180° and west being 270°.

For information about ISS flyovers and other visible satellites, visit www.heavens-above.com

Detailed information regarding all unmanned exploration of our universe, missions past, present, and planned, can be found at Jet Propulsion Laboratories:

http://www.jpl.nasa.gov/

The Planets Visible Without A Telescope

Mars

Mars is now in the constellation Ophiuchus and rises before the Sun sets.  Mars can be seen with Saturn in the southwestern skies about 30 minutes after sunset.  Mars will set by 21:32 p.m. 

Jupiter

The largest planet in the solar system is visible once again in the morning skies.  Jupiter can be found rising by 2:24 a.m. and will be easily visible by 3:10 a.m.    

Saturn

Saturn will be visible about 20 minutes after sunset.  Saturn will remain with us until 20:21 p.m.  Saturn can be found near the bright double star Zubenelgenubi.   

Uranus and Neptune Opposition 2014

The two most distant planets in our solar system will be at their best for the next couple of months.  Neptune has already reached opposition and Uranus will reach opposition on October 7, 2014.  The opposition of a planet is when it is in opposition with the Sun.  What that means is a planet or other body such as an asteroid is seen on the opposite side of the Earth than the Sun is.  From our perspective this is when an object is at its brightest and also coincides with the object’s closest approach to the Earth.  Only objects further from the Sun than we are can be in opposition.

Of the two planets Uranus will be the brightest.  Uranus is already appearing as a 5.8 magnitude object and will continue to brighten until October 7.  Uranus is normally a planet that requires binoculars to be seen but when the planet is nearing opposition dark sky observers can see it with the unaided eye.  Through telescopes observers will resolve Uranus into a small disk shaped object that may display a slight greenish blue color.  Large telescopes using high magnifications up to 300x might be able to discern dark and light patches called albedo features.  These features require large aperture telescopes and better than average viewing conditions to be seen. 

Uranus is currently in the constellation Pisces.  Pisces is very difficult to see in light polluted skies so it is better to start with the Great Square of Autumn.  This asterism connects the constellations Andromeda and Pegasus all of which will be seen high in the eastern sky by 10:00 p.m.  As the Great Square sits high in the east if you follow a line connecting the stars Scheat (Beta Peg) through Algenib (Gamma Peg) about the same distance that lays between the two stars you will find three stars the stand next to one another in a straight line.  The brightest of these stars is Delta Piscium.  Uranus is about four degrees south of these stars.  You will need either a desktop planetarium program or detailed star chart to help you pinpoint which star like object is Uranus. 

http://www.iau.org/static/public/constellations/gif/PSC.gif

http://www.iau.org/static/public/constellations/gif/PEG.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Neptune reached opposition on August 29, 2014.  It is now at its peak brightness of 7.8 magnitude.  This means that you will need at least binoculars to see this distant planet even when it is at its brightest.  Through binoculars Neptune will appear as a dim star like object in the constellation Aquarius.  To find Neptune first locate the bright star Fomalhaut.  About 6 to 10 degrees north of Fomalhaut you will find six bright stars that are shaped like a hyperboloid.  Scanning the sky further north you will find the star Sigma Aquarii.  Neptune will be just east of this star.       

Using a telescope most will see a star like object that when magnified enough will reveal a greyish blue disk.  Using a large telescope and high magnification up to 300x it may be possible to detect albedo features and Neptune largest moon Triton.  Triton will appear as a dim star right next to Neptune.

Like Uranus Neptune will require some kind of astronomy software of a detailed map to find.  As we pass by these planets in our orbit see if you can detect there shift amongst the background stars.  Below are a few links that will be helpful in locating Neptune and the stars mentioned above.

http://www.iau.org/static/public/constellations/gif/AQR.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Constellation of the Month

Each month we will highlight one constellation and some of the objects that can be found within the boundaries of that constellation.  At the start of the month we will list only a few of these objects and each week we will add another to the list.  Some objects will be visible to the unaided eye and some may require a telescope.  Many of the objects listed will require a map of the sky to find or may require repeat observations to notice various properties.  Links to star charts and other information that will be useful in identifying the objects listed will be given at the end of each week’s section. 

This month we will once again forego a single constellation and discuss a number of different patterns.  This month we will work on finding some of the informal groupings of stars called asterisms.  These informal patterns can be large groups that contain multiple constellations or they can be small dim groupings that require a telescope to see. Many of them serve as useful markers in the sky that help you find dimmer and more difficult objects.  

The first asterism we will cover in October is the Summer Triangle.  This is one we have mentioned and used numerous times in the night sky update.  Last week in fact we used it in reference to finding Cygnus the Swan.  Other constellations that comprise this asterism are Lyra the Harp and Aquila the Eagle.  Inside the Summer Triangle we find the constellations Vulpecula the Fox, Sagitta the Arrow and just outside the eastern edge is Delphinus the Dolphin.  Scattered throughout these constellations are many gems for double star observers, numerous open star clusters and a number of nebulas.  The first step in finding all of these is taken by first locating the Summer Triangle.

Also of interest regarding the Summer Triangle is a Mission called Kepler.  This is a space telescope that steadily observed the patch of sky between Cygnus and Lyra.  What Kepler was looking for was the subtle changes in a star’s light due to the effects of a planet orbiting around it.  Thanks to the Kepler mission and other research programs scientists currently have 5,022 candidate exoplanets (planets orbiting other stars) of which 1,746 have been confirmed.  With these numbers scientists have estimated that there are likely as many planets as there are stars in the Milky Way galaxy if not more.  If you would like to learn more about Kepler and the hunt for exoplanets visit http://planetquest.jpl.nasa.gov/  

With a name like the Summer Triangle you would think that we would start losing this asterism soon as we approach winter.  Due to the longer nights we will continue to see the Summer Triangle for the rest of the year.  Tonight go outside and simply look straight up and you should see the three bright stars Deneb, Vega and Altair that define the triangle shape.  Once you can find this asterism grab some binocular and a reclined chair and just start scanning this part of the sky.  Dense star fields and numerous stars clusters will keep you busy for some time. 

The asterism we will cover for the week of October 6 is the Great Square of Autumn.  This is another asterism that can serve as a reference point or guide post in the sky.  Much like the Summer Triangle, the Great Square of Autumn can be used to find a number of constellations and other objects of interest.  The Great Square primarily consists of two constellations; Andromeda and Pegasus.  As most of the square is in Pegasus it is also called the Square of Pegasus.  The Great Square of Autumn can also help you find the constellations Piscis, Cetus, Aquarius, Lacerta and Equuleus. 

One of the more challenging objects the Great Square can help you find is the bright variable star Mira.  Mira is a long period variable that every 333 days or so will brighten from 10th magnitude up to about 3rd magnitude.  This change does not occur in one day but over the entire 333 day cycle.  The brightening of the Mira takes about 100 days and will take twice as long to fade back to minima.  Mira was one of the first variable stars other than bright supernovas or novae to be discovered and it certainly is one of the brightest.  Unfortunately Mira has already peaked in brightness and is already well into its slow downward fade for 2014. 

Mira is an M-class red giant star that is approximately 6 billion years old.  The variable nature of Mira is due to an internal pulsation which is a result of the unstable nature of the star.  The Sun will likely come to a similar state as it evolves into a red giant star in another 5 billion years.  Mira is one of the brightest stars in the constellation Cetus.  Depending on the map you use to find Mira you may find it labeled Omicron Ceti.  

http://www.iau.org/static/public/constellations/gif/CET.gif

Finding the Great Square of Autumn is simple but it does depend on what time you look for it.  After sunset the square will be seen low in the east looking more like a diamond.  At midnight it will be nearly overhead and before sunrise it will be found low in the west. 

For the rest of the month we will cover asterisms that are still helpful guides in the sky but they will be found in individual constellations and will require an optical device such as binoculars to see. 

Our next Star Party will be held on Friday, November 7, 2014, from dusk until 10 p.m.

Weather permitting, the St. Louis Astronomical Society and the Science Center will set up a number of telescopes outdoors and be on-hand to answer your questions.  Telescope viewing begins at 8:00 p.m.  Regardless of the weather on November 7, join us indoors in our planetarium theater for “The Sky Tonight”.  Showtime is at 7 p.m.
This free, indoor star program will introduce you to the current night sky, the planets, and the seasonal constellations. Doors open 15 minutes before show time. Shows begins at 7 p.m. Sorry, no late admissions due to safety issues in the darkened theater.

The St. Louis Astronomical Society hosts the monthly Star Parties at the Science Center which are held on the first Friday of each month. Our Monthly Star Parties are open to the public and free of charge.  For more information about the St. Louis Astronomical Society visit their website at www.slasonline.org

Week of Monday, September 29

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, September 29.  All times are given as local St. Louis time (Central Daylight Time).  For definitions of terminology used in the night sky update, click the highlighted text.

Information updated weekly or as needed.

Join us for our next star party, Friday, October 3, 2014 held in association with the St. Louis Astronomical Society. For details, see the information at the bottom of this page.

The Sun and the Moon

Sunrise is at 6:55 a.m. on Monday, September 29 and sunset is at 6:47 p.m. providing us with about 12 hours of daylight.  Even after sunset, the light from the Sun will still dimly illuminate our sky for about 1.5 hours.  This period of time is called twilight, which ends around 8:15 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 12:51 p.m. this week.

On October 23 the Moon will pass between the Earth and Sun.  This happens once a month during new moon but when they are aligned just right we see the Moon pass in front of the Sun or what is called a solar eclipse.  The October 23 solar eclipse will only be a partial eclipse but it will still be interesting to see.  The eclipse starts for us in St. Louis around 4:41 p.m.  As the Moon gradually moves in front of the Sun you will see a dark disk obscure it.  By 5:47 p.m. which is the greatest extent of the eclipse you will only see about 36% of the Sun covered by the Moon.  If you have a safe means to observe the eclipse you just need to find a high point nearby with a clear view of the west.  If you do not have a safe way to observe the Sun you can tune in to live.slooh.com where they will broadcast the eclipse live.  The eclipse will still be in progress as the sun sets on St. Louis. 

***************************************************************************************************************

Unfortunately solar eclipse can only be safely observed if you have safe solar filters or some kind of projection device.  You should NEVER look directly at the Sun through an unfiltered telescope, binocular, camera or without solar filter glasses. 

Below you will find links that have information about the October 23 partial eclipse, how you can safely observe solar eclipse and why looking at the Sun will cause serious eye damage that could lead to loss of vision.  I would highly recommend reading the eye damage link. 

http://eclipse.gsfc.nasa.gov/OH/OHfigures/OH2014-Fig04.pdf

http://www.mreclipse.com/Totality2/TotalityCh11.html#Pinhole

http://www.mreclipse.com/Special/filters.html       

Moonrise for Monday, September 29 occurs at 12:04 p.m. and moonset will occur at 10:24 p.m.  On Monday, September 29 the Moon will be exhibiting a waxing crescent phase with about 28% of the lunar disk illuminated.  First quarter moon occurs on October 1 at 2:33 p.m.

On Wednesday, October 8 the Moon will pass through the Earth’s shadow treating us to the second total lunar eclipse of 2014.  A lunar eclipse occurs when the Moon passes through the Earth’s shadow.  On October 8 the Moon will begin its slow trek through our shadow at 3:15 a.m.  At 4:14 a.m. it will begin to enter the darkest part of the Earth’s shadow and finally totality will start at 5:25 a.m. and end at 6:24 a.m.

Leading up to totality the Moon will gradually become darker until it is completely within the umbral portion of our shadow.  When this occurs the Moon will usually exhibit a reddish color.  The reason for the color change is that in the umbral portion of Earth’s shadow there is a little light that passes through our atmosphere.  Our atmosphere scatters shorter wavelengths of light but allows for the longer red wavelengths to filter through.  This dim red light is what illuminates the Moon during a total lunar eclipse.  Red is the typical color but coppery shades of yellow can also occur.  The color we see is dependent on how polluted the stratosphere is.  The typical pollutants that affect the Moon’s color are aerosols lofted high into the stratosphere by volcanic eruptions and forest fires. 

You will have to get up early to catch this eclipse but as no two are exactly alike it will be worth losing a few Z’s to catch one of nature’s most beautiful shows.  The same aerosols that affect the Moon’s color during an eclipse can also affect the colors we see during sunrise.  If any ash clouds are over your viewing location sunsets and sunrises can display very vivid purple, pink and orange colors giving the horizon a fiery appearance.  So perhaps while enjoying October’s total lunar eclipse we may also enjoy a beautiful volcanic sunrise.  Below you will find maps and additional information regarding this total lunar eclipse.

http://eclipse.gsfc.nasa.gov/OH/OHfigures/OH2014-Fig03.pdf

http://www.skyandtelescope.com/astronomy-news/observing-news/total-lunar-eclipse-09262014/

International Space Station (ISS) Observing

Visible passes of ISS from St. Louis this week occur during the morning and evening hours.  The best of these are on the mornings of September 30, October 2 and on the evening of October 6.  To learn more about these passes and others follow the links below.

Catch ISS flying over St. Louis in the morning and evening hours starting Monday, September 29. 

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

30 Sep

-3.0

05:24:40

37

NNW

05:25:46

64

NE

05:29:04

10

ESE

01 Oct

-0.7

04:38:22

21

E

04:38:22

21

E

04:39:44

10

ESE

01 Oct

-1.9

06:11:17

14

W

06:13:10

22

SW

06:15:48

10

S

02 Oct

-2.2

05:25:08

32

S

05:25:08

32

S

05:27:19

10

SSE

04 Oct

-0.9

20:23:48

10

SSW

20:24:35

16

SSW

20:24:35

16

SSW

05 Oct

-1.8

19:35:19

10

S

19:37:51

20

SE

19:38:16

20

ESE

06 Oct

-2.8

20:21:47

10

WSW

20:24:38

59

W

20:24:38

59

W

Magnitude (Mag): The Measure of brightness for a celestial object.  The lower the value is, the brighter the object will be.

Altitude (Alt):  The angle of a celestial object measured upwards from the observer’s horizon.

Azimuth (Az):  The direction of a celestial object, measured clockwise from an observer’s location with north being 0°, east being 90°, south being 180° and west being 270°.

For information about ISS flyovers and other visible satellites, visit www.heavens-above.com

Detailed information regarding all unmanned exploration of our universe, missions past, present, and planned, can be found at Jet Propulsion Laboratories:

http://www.jpl.nasa.gov/

The Planets Visible Without A Telescope

Mars

Mars is now in the constellation Libra and rises before the Sun sets.  Mars can be seen with Saturn in the southwestern skies about 20 minutes after sunset.  Mars will continue to pull away from Saturn as it heads into the constellation Scorpius.  Mars will set by 21:40 p.m. 

Jupiter

The largest planet in the solar system is visible once again in the morning skies.  Jupiter can be found rising by 2:45 a.m. and will be easily visible by 3:30 a.m.    

Saturn

Saturn will be visible about 20 minutes after sunset.  Look for it in the south next to Mars which will be visible around the same time.  Saturn will remain with us until 20:47 p.m.  Saturn can be found near the bright double star Zubenelgenubi.     

Uranus and Neptune Opposition 2014

The two most distant planets in our solar system will be at their best for the next couple of months.  Neptune has already reached opposition and Uranus will reach opposition on October 7, 2014.  The opposition of a planet is when it is in opposition with the Sun.  What that means is a planet or other body such as an asteroid is seen on the opposite side of the Earth than the Sun is.  From our perspective this is when an object is at its brightest and also coincides with the object’s closest approach to the Earth.  Only objects further from the Sun than we are can be in opposition. 

Of the two planets Uranus will be the brightest.  Uranus is already appearing as a 5.8 magnitude object and will continue to brighten until October 7.  Uranus is normally a planet that requires binoculars to be seen but when the planet is nearing opposition dark sky observers can see it with the unaided eye.  Through telescopes observers will resolve Uranus into a small disk shaped object that may display a slight greenish blue color.  Large telescopes using high magnifications up to 300x might be able to discern dark and light patches called albedo features.  These features require large aperture telescopes and better than average viewing conditions to be seen. 

Uranus is currently in the constellation Pisces.  Pisces is very difficult to see in light polluted skies so it is better to start with the Great Square of Autumn.  This asterism connects the constellations Andromeda and Pegasus all of which will be seen high in the eastern sky by 10:00 p.m.  As the Great Square sits high in the east if you follow a line connecting the stars Scheat (Beta Peg) through Algenib (Gamma Peg) about the same distance that lays between the two stars you will find three stars the stand next to one another in a straight line.  The brightest of these stars is Delta Piscium.  Uranus is about four degrees south of these stars.  You will need either a desktop planetarium program or detailed star chart to help you pinpoint which star like object is Uranus. 

http://www.iau.org/static/public/constellations/gif/PSC.gif

http://www.iau.org/static/public/constellations/gif/PEG.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Neptune reached opposition on August 29, 2014.  It is now at its peak brightness of 7.8 magnitude.  This means that you will need at least binoculars to see this distant planet even when it is at its brightest.  Through binoculars Neptune will appear as a dim star like object in the constellation Aquarius.  To find Neptune first locate the bright star Fomalhaut.  About 6 to 10 degrees north of Fomalhaut you will find six bright stars that are shaped like a hyperboloid.  Scanning the sky further north you will find the star Sigma Aquarii.  Neptune will be just east of this star.      

Using a telescope most will see a star like object that when magnified enough will reveal a greyish blue disk.  Using a large telescope and high magnification up to 300x it may be possible to detect albedo features and Neptune largest moon Triton.  Triton will appear as a dim star right next to Neptune.

Like Uranus Neptune will require some kind of astronomy software of a detailed map to find.  As we pass by these planets in our orbit see if you can detect there shift amongst the background stars.  Below are a few links that will be helpful in locating Neptune and the stars mentioned above.

http://www.iau.org/static/public/constellations/gif/AQR.gif

http://www.skyandtelescope.com/astronomy-news/observing-news/uranus-and-neptune-in-2014/

Constellation of the Month

Each month we will highlight one constellation and some of the objects that can be found within the boundaries of that constellation.  At the start of the month we will list only a few of these objects and each week we will add another to the list.  Some objects will be visible to the unaided eye and some may require a telescope.  Many of the objects listed will require a map of the sky to find or may require repeat observations to notice various properties.  Links to star charts and other information that will be useful in identifying the objects listed will be given at the end of each week’s section. 

This month we will once again forego a single constellation and discuss a number of different patterns.  This month we will work on finding some of the informal groupings of stars called asterisms.  These informal patterns can be large groups that contain multiple constellations or they can be small dim groupings that require a telescope to see. Many of them serve as useful markers in the sky that help you find dimmer and more difficult objects.  

The first asterism we will cover in October is the Summer Triangle.  This is one we have mentioned and used numerous times in the night sky update.  Last week in fact we used it in reference to finding Cygnus the Swan.  Other constellations that comprise this asterism are Lyra the Harp and Aquila the Eagle.  Inside the Summer Triangle we find the constellations Vulpecula the Fox, Sagitta the Arrow and just outside the eastern edge is Delphinus the Dolphin.  Scattered throughout these constellations are many gems for double star observers, numerous open star clusters and a number of nebulas.  The first step in finding all of these is taken by first locating the Summer Triangle

Also of interest regarding the Summer Triangle is a Mission called Kepler.  This is a space telescope that steadily observed the patch of sky between Cygnus and Lyra.  What Kepler was looking for was the subtle changes in a star’s light due to the effects of a planet orbiting around it.  Thanks to the Kepler mission and other research programs scientists currently have 5,022 candidate exoplanets (planets orbiting other stars) of which 1,746 have been confirmed.  With these numbers scientists have estimated that there are likely as many planets as there are stars in the Milky Way galaxy if not more.  If you would like to learn more about Kepler and the hunt for exoplanets visit http://planetquest.jpl.nasa.gov/  

With a name like the Summer Triangle you would think that we would start losing this asterism soon as we approach winter.  Due to the longer nights we will continue to see the Summer Triangle for the rest of the year.  Tonight go outside and simply look straight up and you should see the three bright stars Deneb, Vega and Altair that define the triangle shape.  Once you can find this asterism grab some binocular and a reclined chair and just start scanning this part of the sky.  Dense star fields and numerous stars clusters will keep you busy for some time. 

Our next Star Party will be held on Friday, October 3, 2014, from dusk until 10 p.m.

Weather permitting, the St. Louis Astronomical Society and the Science Center will set up a number of telescopes outdoors and be on-hand to answer your questions.  Telescope viewing begins at 8:00 p.m.  Regardless of the weather on October 3, join us indoors in our planetarium theater for “The Sky Tonight”.  Showtime is at 7 p.m.
This free, indoor star program will introduce you to the current night sky, the planets, and the seasonal constellations. Doors open 15 minutes before show time. Shows begins at 7 p.m. Sorry, no late admissions due to safety issues in the darkened theater.

The St. Louis Astronomical Society hosts the monthly Star Parties at the Science Center which are held on the first Friday of each month. Our Monthly Star Parties are open to the public and free of charge.  For more information about the St. Louis Astronomical Society visit their website at www.slasonline.org