Night Sky Update - Week of Jan. 17

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Tuesday, January 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, February 3, 2017 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 7:16 a.m. on Tuesday, January 17 and sunset is at 5:06 p.m. providing us with just under 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 6:39 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 12:11 p.m. this week.

Day

Sunrise

Sunset

 17 Jan

7:16 a.m.

5:06 p.m.

 18 Jan

7:16 a.m.

5:07 p.m.

 19 Jan

7:16 a.m.

5:09 p.m.

 20 Jan

7:15 a.m.

5:10 p.m.

 21 Jan

7:14 a.m.

5:11 p.m.

 22 Jan

7:14 a.m.

5:12 p.m.

 23 Jan

7:13 a.m.

5:13 p.m.

 24 Jan

7:13 a.m.

5:14 p.m.

 25 Jan

7:12 a.m.

5:15 p.m.

Moonrise for Tuesday, January 17 occurs at 10:51 p.m. and moonset will occur at 11:00 a.m. on the following day.  On Tuesday, January 17 the Moon will be exhibiting waning gibbous phase with about 71% of the lunar disk illuminated.  The first full moon of 2017 occurs on January 17 at 5:34 a.m.  Last quarter moon occurs on Thursday, January 19 at 4:13 p.m. 

International Space Station (ISS) Observing

Visible passes of ISS from St. Louis for the week of January 17 occur in the morning hours.  The best of these occur on the mornings of January 17 and 18.  Use the table below for information about these and other visible passes of ISS this week.

Catch ISS flying over St. Louis starting Tuesday, January 17                    

 

 

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

18 Jan

-3.4

05:48:48

45

NW

05:49:40

88

NE

05:52:55

10

SE

19 Jan

-1.0

04:59:00

24

E

04:59:00

24

E

05:00:35

10

ESE

19 Jan

-1.4

06:31:41

11

W

06:33:41

17

SW

06:35:53

10

S

20 Jan

-2.4

05:41:57

32

SSW

05:41:57

32

SSW

05:44:36

10

SSE

21 Jan

-0.3

04:52:18

13

SE

04:52:18

13

SE

04:52:45

10

SE


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

Mercury starts 2017 off with a great morning apparition.  On January 19, Mercury will reach greatest western elongation appearing 24° from the Sun.  Currently Mercury rises about 1.5 hours before the Sun.  Due to this your best chance to see Mercury will be to go out around 6:30 a.m. and find a clear southeastern horizon.  Mercury will appear about 8° above the horizon at this time. 

Venus

Venus can be seen low in the west about 20 minutes after sunset in the southwestern sky.  Venus sets by 8:56 p.m. 

Mars

The Red planet is currently found in Aquarius rising before the Sun and can be easily seen 30 minutes after sunset in the southwestern sky.  Mars sets by 9:31 p.m.

Jupiter

The largest planet in our solar system has started another apparition and can be found rising in the east at 11:58 p.m.  It is currently found in the constellation Virgo and is best seen between the hours of 1:00 a.m. and 6:00 a.m. 

Saturn

The king of the rings is visible once again shortly before the Sun rises.  Saturn rises at 4:57 a.m. so your best chance to see it will be around 6:00 a.m. low in the southeastern sky.  Unfortunately the glow of dawn will make things a little difficult.  Additionally trees and buildings may obscure your view.

Uranus and Neptune 2016

Both of the outer gas/ice giants are once again nicely placed in our evening skies.  Both have also reached opposition and as such will rise before the Sun sets.  Both planets will require binoculars to see and as such it will be best to wait until the end of twilight to start your search.  Uranus can be found in the constellation Piscis and Neptune is found in Aquarius.  The brighter of the two planets is Uranus shining with an apparent magnitude of 5.8.  Neptune’s apparent magnitude of 7.9 is within reach of binoculars but light pollution will make it difficult.  For up to date maps of the location of Uranus and Neptune follow the link below or use the free planetarium software Stellarium.

http://www.skyandtelescope.com/observing/celestial-objects-to-watch/planets/ice-giants-neptune-and-uranus/

Constellation of the Month 2017

Over the last couple of years the night sky update has included information for locating a new deep sky object each week.  In 2017 we will change this by highlighting one constellation a month.  The first week of the month will always contain information regarding the constellation, its name, history and other such related topics.  Each week after will highlight a new object to look for.  A variety of objects will be highlighted but each month we will try to have an object that is visible through naked eye, binocular and telescope observations.

The constellation for the month of January is Orion the Hunter.  Arguably the most famous constellation in the sky, Orion can be found in the east shortly after sunset this time of year.  Orion is easily identified by looking for three bright stars in a straight line which represent the belt he is known for.  Moving from east to west the belt stars are named Alnitak, Alnilam and Mintaka.  As the Earth rotates you will find these stars appearing to shift westward.  Around 6:00 p.m. Orion’s Belt can be found low in the east, around 10:00 p.m. it will be due south and near 3:00 a.m. it will be low in the West.  Once you learn to find Orion’s Belt you will notice four bright stars that form a rectangle around it.  The top two stars are named Betelgeuse and Bellatrix and the bottom two are Saiph and Rigel. 

The name Orion is a familiar to many.  Orion is known as the great hunter from Greek mythology who was defeated by the giant scorpion named Scorpius.  Where many of us may know his Greek story his name is not of Greek origin but rather is Sumerian.  This ancient culture developed the first civilization, they were the first scientific astronomers and were the first to have a written language.  Their observations of the sky serves as the platform that modern astronomy stands on.  In Sumerian Orion’s name was Uru-anna meaning light of the sky.  Uru-anna was often associated with Taurus the Bull and the bright star Sirius.  Over time this ancient constellation would be passed down from culture to culture remaining an important reference in the sky. 

For us today Orion remains one of the most recognizable patterns in the sky.  From him we can find numerous other constellations, stars and numerous deep sky objects.  Next week we will start our month of Orion observing with the bright and familiar star; Betelgeuse. 

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

The first object in Orion we will explore is the Red Supergiant star Betelgeuse.  This bright red supergiant star is arguably one of the skies most well-known stars.  It is a monster of a star at 20 times the mass and 1,000 times the size of our Sun.  It is destined to explode in one of nature’s most violent events called a supernova.  It is one of the brightest stars in the sky standing 9th on the list of brightest stars in the sky.  All this after only existing for roughly 10 million years.  Betelgeuse’s time is fleeting due to its enormous size and mass.  Massive stars like Betelgeuse do not exist long due to their rate of fuel consumption.  Most stars are fueled by hydrogen which is smashed together in the heart of a star to produce helium and a bit of energy.  This is an over simplified description of nuclear fusion the process that enriches the universe in heavier elements.  Like all fuel sources the hydrogen at the core of a star becomes deleted inducing stellar evolution.  Betelgeuse has started these changes which will lead to its explosive end about 100,000 years ago. 

Betelgeuse is thought to be about 600 light years away from the Sun.  An exact distance is difficult to find because Betelgeuse is unstable shedding the equivalent of the Sun’s mass in just 10,000 years.  This shed material forms clouds around Betelgeuse that hide the giant stars size making distance measurements difficult.  At its distance of approximately 600 light years Betelgeuse shines with an apparent magnitude of 0.42.  This apparent magnitude changes over time due to the stars unstable nature.  Betelgeuse is listed as a semiregular variable stars with variations occurring roughly every 400 days and 2,100 days.  Betelgeuse’s apparent magnitude can vary from 0.0 to 1.3.

Use the map linked below to help identify Betelgeuse. 

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

Also if you would like to learn more about this amazing star follow this link.

https://www.eso.org/public/usa/news/eso0927/

The object for the week of January 17 is the open star cluster Collinder 70 or what is known as Orion’s Belt.  This group of three bright stars is one of the best known patterns in our winter sky.  It was recognized and used by many cultures including but not limited to the Sumerians, Greeks, Egyptians and Norse.  I  It can help you find the brightest star Sirius, the North Star, a number of constellations and many other targets.  As famous as Orion’s Belt is it is often overlooked that it is a star cluster. 

To the unaided eye Orion’s Belt looks to be three bright stars.  If you were to look at it through any binocular you would quickly discover that it has a number of other stars clustered around it.  Star clusters come in two varieties; globular star clusters are ancient groups of tens of thousands of star that orbit the Milky Way.  Open star clusters are groups of tens to a few thousands of stars which are typically young and the clusters are scattered throughout the Milky Way.  Orion’s Belt is of the latter variety being an open star cluster which contains a bit over 100 stars.  The members of this cluster are about 8 million years old and are estimated to be 800 to 1000 light years away. 

For more information use the following links bellow

http://www.starobserver.eu/openclusters/collinder70.html

https://en.wikipedia.org/wiki/Orion_OB1_Association

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

Our next Star Party will be held on Friday, February 3, 2017, from dusk until 10 p.m.

As part of the Saint Louis Science Center’s First Fridays, 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 once it is dark.  Regardless of the weather on February 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 helps host the monthly Star Parties at the Saint Louis 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. 

 

 

Night Sky Update - Week of Jan. 3

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Tuesday, January 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, January 6, 2017 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 7:19 a.m. on Tuesday, January 3 and sunset is at 4:53 p.m. providing us with roughly 9.5 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 6:22 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 12:06 p.m. this week.

Day

Sunrise

Sunset

 03 Dec

7:19 a.m.

4:53 p.m.

 04 Dec

7:19 a.m.

4:53 p.m.

 05 Dec

7:19 a.m.

4:54 p.m.

 06 Dec

7:19 a.m.

4:55 p.m.

 07 Dec

7:19 a.m.

4:56 p.m.

 08 Jan

7:19 a.m.

4:57 p.m.

 09 Jan

7:19 a.m.

4:58 p.m.

 10 Jan

7:19 a.m.

4:59 p.m.

 11 Jan

7:18 a.m.

5:00 p.m.

 

Moonrise for Tuesday, January 3 occurs at 10:41 a.m. and moonset will occur at 10:29 p.m.  On Tuesday, January 3 the Moon will be exhibiting waxing crescent phase with about 28% of the lunar disk illuminated.  First quarter moon occurs on Thursday, January 5 at 1:47 p.m. 

International Space Station (ISS) Observing

Visible passes of ISS from St. Louis for the week of January 3 occur in the morning hours.  The best of these occurs on the morning of January 5.  Use the table below for information about this and other visible passes of ISS this week.

Catch ISS flying over St. Louis starting Tuesday, January 3                     

 

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

04 Jan

-0.5

05:07:23

13

NE

05:07:23

13

NE

05:07:53

10

NE

04 Jan

-1.1

06:40:27

10

NW

06:41:50

12

NNW

06:43:14

10

N

05 Jan

-1.1

05:50:20

15

N

05:50:20

15

N

05:51:36

10

NNE

12 Jan

-0.8

06:11:18

10

N

06:12:49

13

NNE

06:14:21

10

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

Venus

Venus can be seen low in the west about 20 minutes after sunset in the southwestern sky.  Venus sets by 8:37 p.m. 

Mars

The Red planet is currently found in Aquarius rising before the Sun and can be easily seen 30 minutes after sunset in the southwestern sky.  Mars sets by 9:33 p.m.

Jupiter

The largest planet in our solar system has started another apparition and can be found rising in the east at 12:51 a.m.  It is currently found in the constellation Virgo and is best seen in the eastern sky between the hours of 3:00 a.m. and 6:00 a.m. 

Uranus and Neptune 2016

Both of the outer gas/ice giants are once again nicely placed in our evening skies.  Both have also reached opposition and as such will rise before the Sun sets.  Both planets will require binoculars to see and as such it will be best to wait until the end of twilight to start your search.  Uranus can be found in the constellation Piscis and Neptune is found in Aquarius.  The brighter of the two planets is Uranus shining with an apparent magnitude of 5.8.  Neptune’s apparent magnitude of 7.9 is within reach of binoculars but light pollution will make it difficult.  For up to date maps of the location of Uranus and Neptune follow the link below or use the free planetarium software Stellarium.

http://www.skyandtelescope.com/observing/celestial-objects-to-watch/planets/ice-giants-neptune-and-uranus/

Constellation of the Month 2017

Over the last couple of years the night sky update has included information for locating a new deep sky object each week.  In 2017 we will change this by highlighting one constellation a month.  The first week of the month will always contain information regarding the constellation, its name, history and other such related topics.  Each week after will highlight a new object to look for.  A variety of objects will be highlighted but each month we will try to have an object that is visible through naked eye, binocular and telescope observations.

The constellation for the month of January is Orion the Hunter.  Arguably the most famous constellation in the sky, Orion can be found in the east shortly after sunset this time of year.  Orion is easily identified by looking for three bright stars in a straight line which represent the belt he is known for.  Moving from east to west the belt stars are named Alnitak, Alnilam and Mintaka.  As the Earth rotates you will find these stars appearing to shift westward.  Around 6:00 p.m. Orion’s Belt can be found low in the east, around 10:00 p.m. it will be due south and near 3:00 a.m. it will be low in the West.  Once you learn to find Orion’s Belt you will notice four bright stars that form a rectangle around it.  The top two stars are named Betelgeuse and Bellatrix and the bottom two are Saiph and Rigel. 

The name Orion is a familiar to many.  Orion is known as the great hunter from Greek mythology who was defeated by the giant scorpion named Scorpius.  Where many of us may know his Greek story his name is not of Greek origin but rather is Sumerian.  This ancient culture developed the first civilization, they were the first scientific astronomers and were the first to have a written language.  Their observations of the sky serves as the platform that modern astronomy stands on.  In Sumerian Orion’s name was Uru-anna meaning light of the sky.  Uru-anna was often associated with Taurus the Bull and the bright star Sirius.  Over time this ancient constellation would be passed down from culture to culture remaining an important reference in the sky. 

For us today Orion remains one of the most recognizable patterns in the sky.  From him we can find numerous other constellations, stars and numerous deep sky objects.  Next week we will start our month of Orion observing with the bright a familiar star; Betelgeuse. 

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

 

Our next Star Party will be held on Friday, January 6, 2017, from dusk until 10 p.m.

As part of the Saint Louis Science Center’s First Fridays, 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 once it is dark.  Regardless of the weather on January 6, 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 helps host the monthly Star Parties at the Saint Louis 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. 

 

 

 

Night Sky Update - Week of December 20

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Tuesday, December 20.  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 6, 2017 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 Tuesday, December 20 and sunset is at 4:43 p.m. providing us with roughly 9.5 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 6:18 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 11:59 a.m. this week.

The first day of winter will occur this week on December 21. This day is called the Winter Solstice which has been celebrated by ancient and modern cultures around the world. The winter solstice marks the day when one end of Earth’s axis is pointed away from the Sun due to Earth’s tilt. For northern hemisphere observers this occurs in December and for those in the southern hemisphere it occurs in June. 

It might come as a surprise that our winters in the northern hemisphere coincide with Earth’s nearest point to the Sun. This point is called perihelion which occurs on January 4, 2017. At perihelion the Earth is roughly 91 million miles from the Sun. To learn more about the solstice and Earth’s seasons visit http://aa.usno.navy.mil/faq/docs/seasons_orbit.php

Day

Sunrise

Sunset

 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.

 23 Dec

7:16 a.m.

4:45 p.m.

 24 Dec

7:17 a.m.

4:45 p.m.

 25 Dec

7:17 a.m.

4:46 p.m.

 26 Dec

7:18 a.m.

4:46 p.m.

 27 Dec

7:18 a.m.

4:47 p.m.

 28 Dec

7:18 a.m.

4:48 p.m.

 

Moonrise for Tuesday, December 20 occurs at 11:59 a.m. on the preceding day and moonset will occur at 11:58 a.m.  On Tuesday, December 20 the Moon will be exhibiting its last quarter phase with about 50% of the lunar disk illuminated. 

International Space Station (ISS) Observing

Visible passes of ISS from St. Louis for the week of December 20 occur in the morning and evening hours. The best of these occurs on the evening of December 20. Use the table below for information about this and other visible passes of ISS this week.

Catch ISS flying over St. Louis starting Tuesday, December 20                

 

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

20 Dec

-0.6

18:06:04

10

W

18:08:41

22

SW

18:11:17

10

S

21 Dec

-1.9

17:13:38

10

WNW

17:16:47

43

SW

17:19:56

10

SSE

28 Dec

-0.2

06:17:30

10

S

06:19:50

19

SE

06:22:11

10

E

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

Venus

Venus can be seen low in the west about 20 minutes after sunset in the southwestern sky.  Venus sets by 8:13 p.m. 

Mars

The Red planet is currently found in Aquarius rising before the Sun and can be easily seen 30 minutes after sunset in the southwestern sky.  Mars sets by 9:35 p.m.

Jupiter

The largest planet in our solar system has started another apparition and can be found rising in the east at 2:01 a.m.  It is currently found in the constellation Virgo and is best seen in the eastern sky between the hours of 3:00 a.m. and 6:00 a.m. 

Uranus and Neptune 2016

Both of the outer gas/ice giants are once again nicely placed in our evening skies.  Both have also reached opposition and as such will rise before the Sun sets.  Both planets will require binoculars to see and as such it will be best to wait until the end of twilight to start your search.  Uranus can be found in the constellation Piscis and Neptune is found in Aquarius. 

The brighter of the two planets is Uranus shining with an apparent magnitude of 5.8.  Neptune’s apparent magnitude of 7.9 is within reach of binoculars but light pollution will make it difficult.  For up to date maps of the location of Uranus and Neptune follow the link below or use the free planetarium software Stellarium.

http://www.skyandtelescope.com/observing/celestial-objects-to-watch/planets/ice-giants-neptune-and-uranus/

Deep Sky Object of the Week

A few years ago the night sky update included a section that highlighted one constellation a month and a few objects of interest inside of it.  Unfortunately of the 88 constellations there are only about 60 we can see in St. Louis and of these there are only so many that have enough objects to reference that would interest both beginners and advanced observers. 

In 2015 we changed things a bit for this section and instead of highlighting one constellation for each month we highlighted one Messier object a week using the Astronomical League’s Binocular Messier program as our guide.  We will continue this into 2016 but instead of using the Astronomical League’s binocular Messier program we will use their Binocular Deep Sky Program.    

The Astronomical League is an amateur astronomy society that is composed of over 240 local amateur astronomy societies across the United States and includes members at large and other supporting members.  Their goal is to promote the science of astronomy through education, incentive and communication. 

One of the many ways the Astronomical League has assisted amateur astronomers around the world is by creating various observing programs that highlight different aspects of astronomy and how an amateur astronomer can observe the sky and learn more about astronomy in doing so.  Some of these programs are introductory and are targeted at those beginning to learn about observational astronomy and some are extremely advanced, require specialized equipment and require a large amount of time to complete.  These observing programs cover most any type of object or way to observe the sky so everyone should be able to find one that matches their interests and abilities. 

It is important to note that these programs are not part of any class or lecture series but are rather lists of objects that highlight types of objects or observing methods relevant to astronomy.  Taking part in these programs is done under one’s own choice.  To officially complete each program you do have to be a member of the Astronomical League but you do not have to join to use them as observing guides or education tools.  I would urge anyone interested in astronomy to look at these programs as they will help organize observing sessions and will help refine observing skills you already have.  You can find out more information about the Astronomical League’s observing programs here https://www.astroleague.org/observing.html

The observing program we will use to help guide us through the 2016 observing year is the Binocular Deep Sky Program.  This is a program that will appeal to both beginning and advance observers.  Too often it is thought that you need to have a telescope for astronomical observations.  Telescopes make great observing tools and yes they can show you more than binoculars but they do have their limitations.  Cost, size, weight and complexity will often be a surprise to people when they first learn about telescopes.  These factors can keep people from using telescopes they own or from buying one at all.  The best advice to follow is a good observing tool is one you will use. 

The binocular deep sky program is an introduction to deep sky objects beyond the Messier catalog.  It will introduced viewers to the New General Catalog (NGC) and some of the lesser known deep sky catalogs such as the Stock, Collinder and Melotte.  Each week we will highlight a deep sky object that is part of the Astronomical League’s binocular deep sky program.  This program is tougher than Messier binocular program as the objects are not always as obvious and they will require larger binoculars than the Messier program.  50mm binoculars are recommended but many of the targets can be seen through smaller aperture instruments. 

I would urge each observer to fulfill the requirements of the program even if you do not intend to join the League for completion.  The requirements involve logging observing data that can help refine observing skills that will be useful later down the road.  If you have an interest in astronomy and learning more about observational astronomy I would also recommend checking out one of the two excellent astronomy societies near St. Louis.  Both are members of the Astronomical League and both do numerous public observing nights around town.  These clubs are the

St. Louis Astronomical Society and

Astronomical Society of Eastern Missouri

If you do not live in the St. Louis, Missouri area chances are you have similar astronomical societies where you live. 

The deep sky object for the week of November 29 is the open star cluster Trumpler 2 (Tr 2).  This open star cluster is part of the Trumpler catalog of star clusters studied by astronomer Robert Julius Trumpler.  He is famous for studying the magnitudes of distant star clusters and noting that they appeared redder than expected.  This was found to be caused by interstellar dust that absorbed some of the light from these more distant stars.  Trumpler is also the astronomer that developed the Trumpler classification system used to categorize open star clusters.  This catalog remains in use today and is a common reference for the night sky update. 

Tr 2 is a group of 20 stars estimated to be 78 million years old.  At a distance of 2,000 light years Tr 2 shines with an apparent magnitude of 5.9 making it an easy target for binoculars.  Its Trumpler classification is III, 2, p meaning it is detached from background stars with no central concentration, it has a moderate range of stellar magnitudes and it has a poor population with less than 50 members. 

Tr 2 is found in the constellation Perseus which is easily found high in the north northeast by 6:00 p.m.  It is easiest to find our target by locating the constellation Cassiopeia first.  Cassiopeia appears as a bright W-shape of stars and can be found in the northeast by 6:00 p.m. Next step is to identify the stars Gamma and Delta Cassiopeiae and start hop from them to the southwest. Following this path for roughly 15° will bring you to a bright star called Eta Persei.  As you followed this path you should have seen the Perseus Double Cluster (NGC 869 and NGC 884).  If you can find these Tr 2 is about halfway between them and Eta Persei. 

Tr 2 will appear as a loose group of stars that covers a 19’ (arc minute) area of sky.  For comparison that is a little more than half of the Moon’s apparent size in the sky.  Due to its large scattered appearance it will be helpful to use a planetarium software to help track down the exact location.  For a start use the maps linked below.

https://en.wikipedia.org/wiki/Trumpler_2#/media/File:Tr_2_map.png

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

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

The deep sky object for the week of December 6 is the open star cluster Trumpler 3 (Tr 3).  Like last week’s star cluster Tr 3 is part of the Trumpler catalog of open star clusters.  It is a rather obscure object that will be difficult to see not due to its brightness but rather due to its scattered appearance.  Tr 3 is made up of 30 stars that are thought to be roughly 70 million years old.  At a distance of 2,250 ly Tr 3 shines with an apparent magnitude of 7.0.  The Trumpler classification for Tr 3 is III, 3, p which means it is detached from background stars with no concentration, It has a wide range of stellar magnitudes and it has a poor stellar population having less than 50 stars.

Tr 3 is located in the constellation Cassiopeia. To begin your search look north around 6:00 p.m. and you will find the W-shape of Cassiopeia.  Next use the attached map to identify the stars Gamma and Epsilon Cassiopeiae.  Once you have identified these stars use those to star hop to the west and you will find the Tr 6 about 6° from Epsilon Cassiopeiae.  This will be a difficult cluster to identify due to its scattered nature.  It covers about 22 arc minutes of sky which about 2/3 of the full moon’s angular appearance.  In addition to maps I will link an image of Tr 3 for a visual reference.  It is also recommended that you use a desktop planetarium software to help locate Tr 3.

https://en.wikipedia.org/wiki/Trumpler_3#/media/File:Tr_3_map.png

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

https://en.wikipedia.org/wiki/Trumpler_3#/media/File:Tr_3.png

The deep sky object for the week of December 13 is the open star cluster Melotte 20 (Mel 20).  Another name for Mel 20 is the Alpha Persei Moving Group.  Moving groups of stars are the remnants of stellar associations the drift through the galaxy.  The namesake for this moving group is the bright star Mirfak located in the constellation Perseus.  At a distance of 601 light years Mel 20 shines with an apparent magnitude of 1.2.  This puts it well within naked eye visibility even in the city.  Visually it will appear as a bright scattering of stars that has a pine tree shape.  To see the pine tree shape you will need to use your binoculars.  The bright star Mirfak is near the top of the tree shape. 

To find Mel 20 you need to locate the constellation Perseus.  This is easily done by first looking for the W-shape of Cassiopeia high in the north northeastern sky by 6:00 p.m.  Once you have found Cassiopeia follow the stars Gamma and Delta Cassiopeiae to the southwest.  Not long after you do this you will encounter a long bright chain of stars.  This is the constellation Perseus.  The first bright star you will find in Perseus is Eta Persei followed by Gamma and then Alpha or what will be labeled as Mirfak.  Once here you will find a number of bright stars that are well detached from background stars.  This is Mel 20.  Use the maps and image below to help identify this bright open star cluster.

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

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

https://en.wikipedia.org/wiki/Alpha_Persei_Cluster#/media/File:Alpha_Persei_Cluster.png

The deep sky object for the week of December 20 is the open star cluster NGC 1342.  This star cluster is found in the constellation Perseus at a distance of 1,800 light years.  There are 40 stars known to be part of this star cluster which formed about 300 million years ago. With a distance of 1,800 light years NGC 1342 shines with an apparent magnitude of 6.7.  Its Trumpler classification is III, 3, p meaning it is well detached from background stars with no concentration, it has a wide variance of stellar magnitudes and it has a poor stellar population having less than 50 stars. 

To find NGC 1342 you will have to find the constellation Perseus.  The easiest way to do this is first find the constellation Cassiopeia.  She can be found high in the northern sky by 6:00 p.m. and is distinguished by a bright W-shape of stars.  Once here look for a long bright chain of stars that runs from her west side down towards the southeast.  This bright chain of stars is Perseus.  It appears to run from Cassiopeia all the way to the Pleiades star cluster in Taurus the Bull.  Once you have identified Perseus use the map linked below to identify the Stars Menkib and Algol.  Once you can do this grab your binoculars and scan back and forth between these stars.  About halfway between them is where you will find the star cluster NGC 1342.  Use the links below help in locating NGC 1342.

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

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

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

https://it.wikipedia.org/wiki/NGC_1342#/media/File:NGC_1342_map.png

Our next Star Party will be held on Friday, January 6, 2016, from dusk until 10 p.m.

As part of the Saint Louis Science Center’s First Fridays, 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 once it is dark.  Regardless of the weather on January 6, 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 helps host the monthly Star Parties at the Saint Louis 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.  

The Saint Louis Science Center offers a variety of hands-on science programs and workshops for your class, scouts, afterschool functions, families, parties, fairs, festivals, church groups, camps and more. We also have programs for adults! We offer programs at the Science Center, or we can bring our programs to you*!

NIGHT SKY UPDATE for the week of Wednesday, September 7, 2016

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Wednesday, September 7.  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 7, 2016 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 6:36 a.m. on Wednesday, September 7 and sunset is at 7:21 p.m. providing us with just under 13 hours of daylight.  Even after sunset, the light from the Sun will still dimly illuminate our sky for a little over 1.5 hours.  This period of time is called twilight, which ends around 8:52 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 12:59 p.m. this week.

 

Day

Sunrise

Sunset

     

 07 Sep

6:36 a.m.

7:21 p.m.

 08 Sep

6:37 a.m.

7:19 p.m.

 09 Sep

6:38 a.m.

7:18 p.m.

 10 Sep

6:39 a.m.

7:16 p.m.

 11 Sep

6:39 a.m.

7:15 p.m.

 12 Sep

6:40 a.m.

7:13 p.m.

 13 Sep

6:41 a.m.

7:11 p.m.

 14 Sep

6:42 a.m.

7:10 p.m.

 

Moonrise for Wednesday, September 7 occurs at 11:25 a.m. and moonset will occur at 10:24 p.m.  On Tuesday September 6 the Moon will be exhibiting a waxing crescent phase with 25% of the lunar disk illuminated.  First quarter moon occurs on September 9 at 6:49 a.m. 

International Space Station (ISS) Observing 

Visible passes of ISS from St. Louis for the week of September 6 occur in the morning hours. The best of these occur on the mornings of September 8 and 9.  Use the table below for information about these and other visible passes of ISS this week.

Catch ISS flying over St. Louis starting Tuesday, September 6.       

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

08 Sep

-1.0

04:18:04

25

ENE

04:18:04

25

ENE

04:19:38

10

ENE

08 Sep

-1.5

05:50:43

11

WNW

05:53:06

20

NNW

05:55:38

10

NNE

09 Sep

-2.2

05:00:24

32

NNW

05:00:24

32

NNW

05:03:22

10

NE

10 Sep

-0.5

04:10:00

18

NE

04:10:00

18

NE

04:11:00

10

NE

10 Sep

-0.8

05:43:06

10

NW

05:44:46

13

NNW

05:46:28

10

NNE

11 Sep

-1.1

04:52:13

18

NNW

04:52:13

18

NNW

04:54:18

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

Venus

Venus can be seen low in the west about 20 minutes after sunset in the western sky.  Venus sets by 8:20 p.m. 

Mars

The Red planet is currently found in Scorpius rising before the Sun and can be easily seen 30 minutes after sunset in the southern sky.  Mars sets by 11:26 p.m.

Jupiter

Jupiter now sets as twilight is ending so get your observations in while you can. To see Jupiter you will have to look to the west about 20 minutes after sunset.  Jupiter sets at 7:54 p.m. 

NASA’s Juno mission arrived at Jupiter on Monday, July 4.  Juno’s primary mission started with orbital insertion on July 4, 2016 and will end when the spacecraft is deorbited allowing the spacecraft to descend into the crushing atmosphere of Jupiter in February 2018.  Over 20 months Juno will complete 37 orbits during which the spacecraft will investigate Jupiter’s core and magnetic field, measure the amount of ammonia and water in Jupiter’s deep atmosphere and it will observe the planet’s aurora and charged particle environment.  To learn more visit https://www.nasa.gov/mission_pages/juno/main/index.html

Saturn

The ringed planet is has reached opposition and as such rises before the Sun sets.  Look for Saturn alongside Mars in the southern sky about 30 minutes after sunset.  Saturn will set by 11:15 p.m.

Uranus and Neptune 2016

Both of the outer gas/ice giants are once again nicely placed in our late evening skies.  Neptune rises first around 7:07 p.m. and Uranus follows a couple of hours later rising at 8:51 p.m.  Neptune reached opposition on September 2 and will be at its brightest during the month of September.  With our current weather conditions Neptune has been elusive in binoculars but for those with 42mm or larger binoculars should be able to find Neptune at its current apparent magnitude of 7.8. 

Uranus is found in Pisces and will reach opposition on October 15 this year.  It is already shining with an apparent magnitude of 5.7 making it an easy target in any binocular.  It may grow bright enough that if in dark skies keen observers could see it naked eye.

For up to date maps of the location of Uranus and Neptune follow the link below or use the free planetarium software Stellarium.

http://www.skyandtelescope.com/observing/celestial-objects-to-watch/planets/ice-giants-neptune-and-uranus/

A few years ago the night sky update included a section that highlighted one constellation a month and a few objects of interest inside of it.  Unfortunately of the 88 constellations there are only about 60 we can see in St. Louis and of these there are only so many that have enough objects to reference that would interest both beginners and advanced observers.  In 2015 we changed things a bit for this section and instead of highlighting one constellation for each month we highlighted one Messier object a week using the Astronomical League’s Binocular Messier program as our guide.  We will continue this into 2016 but instead of using the Astronomical League’s binocular Messier program we will use their Binocular Deep Sky Program.    

 

The Astronomical League is an amateur astronomy society that is composed of over 240 local amateur astronomy societies across the United States and includes members at large and other supporting members.  Their goal is to promote the science of astronomy through education, incentive and communication. 

 

One of the many ways the Astronomical League has assisted amateur astronomers around the world is by creating various observing programs that highlight different aspects of astronomy and how an amateur astronomer can observe the sky and learn more about astronomy in doing so.  Some of these programs are introductory and are targeted at those beginning to learn about observational astronomy and some are extremely advanced, require specialized equipment and require a large amount of time to complete.  These observing programs cover most any type of object or way to observe the sky so everyone should be able to find one that matches their interests and abilities.  It is important to note that these programs are not part of any class or lecture series but are rather lists of objects that highlight types of objects or observing methods relevant to astronomy.  Taking part in these programs is done under one’s own choice.  To officially complete each program you do have to be a member of the Astronomical League but you do not have to join to use them as observing guides or education tools.  I would urge anyone interested in astronomy to look at these programs as they will help organize observing sessions and will help refine observing skills you already have.  You can find out more information about the Astronomical League’s observing programs here https://www.astroleague.org/observing.html

 

The observing program we will use to help guide us through the 2016 observing year is the Binocular Deep Sky Program.  This is a program that will appeal to both beginning and advance observers.  Too often it is thought that you need to have a telescope for astronomical observations.  Telescopes make great observing tools and yes they can show you more than binoculars but they do have their limitations.  Cost, size, weight and complexity will often be a surprise to people when they first learn about telescopes.  These factors can keep people from using telescopes they own or from buying one at all.  The best advice to follow is a good observing tool is one you will use. 

 

The binocular deep sky program is an introduction to deep sky objects beyond the Messier catalog.  It will introduced viewers to the New General Catalog (NGC) and some of the lesser known deep sky catalogs such as the Stock, Collinder and Melotte.  Each week we will highlight a deep sky object that is part of the Astronomical League’s binocular deep sky program.  This program is tougher than Messier binocular program as the objects are not always as obvious and they will require larger binoculars than the Messier program.  50mm binoculars are recommended but many of the targets can be seen through smaller aperture instruments.  I would urge each observer to fulfill the requirements of the program even if you do not intend to join the League for completion.  The requirements involve logging observing data that can help refine observing skills that will be useful later down the road.  If you have an interest in astronomy and learning more about observational astronomy I would also recommend checking out one of the two excellent astronomy societies near St. Louis.  Both are members of the Astronomical League and both do numerous public observing nights around town.  These clubs are the

St. Louis Astronomical Society and

Astronomical Society of Eastern Missouri

If you do not live in the St. Louis, Missouri area chances are you have similar astronomical societies where you live. 

 

The deep sky object for the week of September 6 is the open star cluster NGC 7789.  Located in the constellation Cassiopeia, NGC 7789 will be seen tracking through the circumpolar sky all night long.  At a distance of 6,200 light years this star cluster shines with an apparent magnitude of 6.7 making it an easy target for most binoculars.  The 300 stars in this rich star cluster are estimated to be 1.6 billion years old.  On Earth when these stars first started to shine it is believed a supercontinent named Columbia was still the dominant landmass of the Earth. 

 

NGC 7789 has a Trumpler classification of II, 1, r; meaning it is well detached from background stars with little central concentration, it has very little variance in stellar magnitudes and it has a rich population with over 100 stars. 

 

To find NGC 7789 you have to locate the W-shape of Cassiopeia.  To do this simply look northeast about 10:00 p.m. and Cassiopeia will be easily seen from dark or light polluted skies.        

Next identify the bright star Beta Cassiopeiae which is the western most star in the W-shape.  From here grab your binocular and scan to the southwest about 2° until you find the star Rho Cassiopeiae.  Once here scan about 1° south and you will find NGC 7789.  It will appear as a fuzzy patch of light through most binoculars.  Use the links below for help in locating NGC 7789.

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

https://en.wikipedia.org/wiki/NGC_7789#/media/File:NGC_7789_map.png

 

As an additional treat this week I recommend doing some research on the guide star Rho Cassiopeiae.  This star is a rare yellow hypergiant and is one of 12 that has been found in the Milky Way.  These are rare stars because they are extremely massive and unstable.  This star has the mass equivalent of roughly 30 stars.  The unstable nature of stars like Rho Cassiopeiae cause them to shed off about 1/100,000 of its mass per year.  This may seem like a small number but compared to the Sun that is hundreds of millions of times more than the Sun loses each year.  Yellow Hypergiants are believed to be an evolutionary stage of massive stars as they evolve from their red supergiant stage into a luminous blue variable star. 

Rho Cassiopeiae is about 8,200 light years away but yet it is visible to the naked eye.  The reason is it is about 500,000 times more luminous than our Sun.  So even at its great distance it appears quite bright.  About every 50 years the star dims by about 2 magnitude because it pumps much of its gas into its expansive atmosphere.  This causes the star to cool dramatically appearing as a cool M-class star.  About a year after this Rho Cassiopeiae returns to its normal magnitude.  The last time this happened was in 2000-2001.  This is also a star that is destined to go supernova.  Due to its mass loss it will likely end as a Type Ib or Type Ic supernova.  

Our next Star Party will be held on Friday, October 7, 2016, from dusk until 10 p.m.

As part of the Saint Louis Science Center’s First Fridays, 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 once it is dark.  Regardless of the weather on October 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 helps host the monthly Star Parties at the Saint Louis 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. 

 

 

 

2016 Loeb Prize Winner

CENTRAL VISUAL AND PERFORMING ARTS HIGH SCHOOL TEACHER WINS 2016 LOEB PRIZE  

The 2016 Loeb Prize Ceremony was held on May 17th, 2016. First place went to Jason McClelland of Central Visual and Performing Arts High School. Ashley McMichael of Gateway STEM High School won second place. The runners-up were Bethany Feucht of Signal Hill School District, Ginger Johnson of O'Fallon Township High School, and Dr. Kelly Taylor of Carnahan High school. 

Congratulations to Jason and all the other Loeb Prize winners! And thank you to all the nominated teachers who make a difference in the lives of their students every day. 

The Loeb Prize, established in 1996 and endowed in 2002 by the Loebs’ gift, honors effective teaching as a central component of quality education. It is one way in which the Loebs and the Science Center demonstrate their commitment to teaching professionals and to elevating public appreciation for teachers’ efforts.

 

“All of our finalists this year demonstrated expertise in their subject areas, innovative teaching styles including the use of technology, and their personal commitment to the overall well-being of their students,” said Mrs. Loeb. “I am grateful for the opportunity to recognize these teachers for the work they do to enable their students to become the STEM (science, technology, engineering, and mathematics) leaders of tomorrow.”

Week of Monday, August 18.

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, August 18.  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, September 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 6:18 a.m. on Monday, August 18 and sunset is at 7:51 p.m. providing us with about 14 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 9:29 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 1:05 p.m. this week. 

Moonrise for Monday, August 18 occurs at 12:26 a.m.  Moonset will occur at 2:54 p.m. on the following day.  On Monday, August 18 the Moon will be exhibiting a waning crescent phase with roughly 38% of the lunar disk illuminated.  New moon occurs on August 25, 2014. 

International Space Station (ISS) Observing

This week visible passes of ISS are evening passes.  The best of these occur on the evenings 19, 22 and 23of August.  To learn more about these passes and others this week use the information below.

Catch ISS flying over St. Louis in evening hours starting Monday, August 18. 

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

18 Aug

-1.1

20:56:41

10

NNW

20:59:07

19

NNE

21:01:08

12

ENE

18 Aug

-0.6

22:32:50

10

NW

22:34:01

20

WNW

22:34:01

20

WNW

19 Aug

-2.9

21:44:23

10

NW

21:47:21

58

N

21:47:21

58

N

20 Aug

-2.3

20:56:01

10

NW

20:59:10

37

NNE

21:00:43

23

E

20 Aug

-0.2

22:33:06

10

W

22:33:36

13

W

22:33:36

13

W

21 Aug

-1.7

20:07:44

10

NNW

20:10:33

25

NNE

20:13:22

10

E

21 Aug

-2.2

21:44:14

10

WNW

21:47:02

38

WSW

21:47:02

38

WSW

22 Aug

-3.3

20:55:36

10

NW

20:58:56

76

SW

21:00:31

28

SE

23 Aug

-3.0

20:07:07

10

NW

20:10:25

59

NE

20:13:42

10

ESE

23 Aug

-0.7

21:45:06

10

W

21:46:47

13

SW

21:46:58

13

SW

24 Aug

-1.3

20:55:41

10

WNW

20:58:26

24

SW

21:00:36

13

S

25 Aug

-2.3

20:06:48

10

WNW

20:10:00

43

SW

20:13:10

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

Venus

Venus is now well within its current morning apparition. It rises around 4:49 a.m. becoming visible after 5:15 a.m.  Venus is currently exhibiting a gibbous phase with roughly 95% of the Venusian disk illuminated.

Mars

Mars is now in the constellation Libra and rises before the Sun sets.  For those awake around 9:00 p.m. you will see a reddish-orange object high in the southwest.  We have now passed by Mars in our orbit and will continue to move further away each day.  Mars will set by 22:57 p.m. 

Jupiter

The largest planet in the solar system is starting to join us once again in the morning skies.  Jupiter can be found rising by 4:49 a.m. becoming visible by 5:15 a.m.  Look for Jupiter and Venus together in the morning skies.  If you watch the two planets over the rest of the month you will notice Jupiter is moving higher in the sky each day while Venus is getting lower in the east each day.  This wandering of the planets is what made ancient astronomers name the planets Aster Planetes or wandering stars.  

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 23:23 p.m.  Saturn can be found near the bright double star Zubenelgenubi.    

Keep an eye on Mars and Saturn as the two are approaching each other in the sky.  Later this year Mars will pass Saturn on its way into the constellation Scorpius. 

Comet Jacques (C/2014 E2)

There is another binocular comet that has been cruising through the early morning skies for most of the summer.  It is now near the constellation Perseus making it visible not long after midnight.  Comet Jacques (C/2014 E2) was discovered earlier this year in March by the SONEAR observatory team.  It is a long period comet that is estimated to take roughly 22,000 years to orbit the Sun.  It is now on its way back out of the inner solar system and will continue to fade as it gets further from the Sun. 

To find Comet Jacques (C/2014 E2) first look for the constellation Cassiopeia.  She will be seen as a bright W-shape of stars rising in the northeast.  The western half of the W-shape will point you down to the constellation Perseus.  About halfway down Perseus you will see a bright and broad group of stars called the Alpha Perseii Moving Group.  This star cluster is dominated by a bright star at its center called Mirfak or Alpha Perseii.  Comet Jacques (C/2014 E2) will be passing by this star cluster as it skirts the boundary between Perseus and Camelopardalis.  By the end of the week Comet Jacques (C2014 E2) will be in Cassiopeia. 

The last time I was able to observe this comet it was nearing 7th magnitude on a night when there was considerable light pollution from the Moon.  Even with a gibbous moon drowning out much of the sky I was still able to spot Comet Jacques (C/2014 E2) through a number of different binoculars.  It was easy to see with 10x50 and 8x42 binoculars, it was a bit tougher in 7x35 binoculars and through cheapo 10x25 binoculars I thought I was just barely able to detect the faint glow of the comet.  It goes to show that you don’t need to go buy a giant telescope to see some of the amazing objects the sky has to offer. 

Below are a number of links to maps and other information that will be helpful.  If you have any questions regarding this comet feel free to send an email to spacequestions@slsc.org.

http://freestarcharts.com/images/Articles/Month/Aug2014/Comet_Jacques/C2014_E2_Jacques_Aug14_Finder_Chart.pdf

http://www.aerith.net/comet/catalog/2014E2/2014E2.html

http://heavens-above.com/skychart.aspx?lat=38.627&lng=-90.1994&loc=St.+Louis&alt=141&tz=CST

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. 

For August we are going to do things a little different again. This month we will visit three constellations that contain an object called a star cloud.  These are virtually dust free windows into the larger structures of the Milky Way.  This type of object is typically missed by those of us that observe from light polluted locations like St. Louis as the dim glow of the Milky Way’s concentration is washed from view.  The constellations we will visit to find these are Sagittarius, Scutum and Cygnus. 

Star clouds are fascinating structures.  Again they are virtually dust free windows into the larger structures of the Milky Way.  A good analogy for this is to imagine an overcast day.  As you scan the cloudy sky you come across a hole in the clouds giving you an unobscured view of the blue sky.  Just like atmospheric clouds obscure the sky behind them, clouds of dust and gas in our galaxy will obscure the stars that are positioned behind them.  Scattered along the dim glow of the Milky Way are relatively dust free zones that offer bright unobscured views of the dense and distant star fields of the Milky Way’s spiral arms.  Even though a great deal of what star clouds offer is lost to observers with light polluted skies they still offer large vistas of denser star fields and often contain some of the most striking deep sky objects to look for.

When observing these large features in the sky it is best to star with binoculars.  They offer a much wider field of view and can take in more of the dense star field.  Once you have done this for a while then try pointing a telescope into the star clouds. This will yield views of more specific objects such as open star clusters, double/multiple stars and various nebulas. 

The first star cloud we will look at is the Great Sagittarius Star Cloud (GSSC).  As the name implies this star cloud is located in the constellation Sagittarius.  This famous constellation can be found in our southern skies during the summer months.  Due to its low altitude Sagittarius may be hard for some to see if you have tall buildings or trees south of your viewing location.  Finding Sagittarius is pretty simple.  First locate a large fishhook shape of stars in the south.  This is the constellation Scorpius.  Just east of the fishhook you will find another bright group of stars in shape of a stovetop teapot.  This is called the teapot asterism which is the bright part of the constellation Sagittarius. 

Once you have found the Teapot asterism grab some binoculars and scan the patch of sky near the spout of the teapot.  Here is where you will find the Great Sagittarius Star Cloud.  For those of us in light polluted skies this part of the sky will have a noticeably denser star field.  The part of the Milky Way we are looking at here is the Sagittarius arm of the galaxy that sits between us and the center of our galaxy.  Many of the stars you will be able to see in binoculars lie at distances between 6,500 and 13,000 lights years away.  Even in light polluted skies there are thousands of stars scattered in this relatively small patch of sky. 

Getting out to dark skies is where you will see why these structures are called star clouds.  With just the unaided eye the dense fields of these relatively dust free windows into the depths of the Milky Way will be much brighter than the rest of the dust obscured parts of our galaxy’s concentration.  The glow you see here is representative of millions of stars that lie closer to the Milky Way’s core than we do. 

Once you have scanned and taken in the entire star cloud there are a number of other objects that stand out in the same area.  M7 or Ptolemy’s cluster is an open cluster that is much closer to us than the GSSC is.  It will be easily seen as a bright group of roughly 80 stars on the southern boundary of the star cloud.  At only 800 light years away this group of stars is in the same arm (Orion Spur) of the galaxy that the Sun is.  On the north edge of the GSSC is a bright emission nebula called M8 or the Lagoon Nebula.  This is an area where stars are actively forming that lies at about 5,200 light years away.  This stellar nursery is part of the Sagittarius arm of our galaxy and can be easily spotted with small binoculars.  In fact if you scan north of M8 you will find three more nebulae that are also in the Sagittarius arm.  These are named M20, M17 and M16. 

In addition to these nebulae there are a number of open star clusters scatter around the GSSC that can be seen but many will go unnoticed if you just quickly scan through the sky.  Most of the cluster will be around 8th or 9th magnitude and contain fewer than 100 stars. 

To get as much out of the GSSC you will need to spend some quality time soaking in the light for these distant stars.  I would recommend starting with binoculars no larger than 10 x 50.  There will be numerous double stars to identify and a hand full of deep sky objects as well.  Having a desktop planetarium software handy will help you identify some of these but a more detailed database will be required for fainter less obvious objects.  Below you will find basic maps of Sagittarius and Scorpius that will aid you in finding the GSSC and the brighter deep sky objects listed above. 

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

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

The star cloud for August 11 is called the Small Sagittarius Star Cloud (SSSC).  Even though the name implies it is lesser in nature this is the densest and my favorite of the star clouds we will look at this month.  The SSSC is also known as M24 as it was one of the objects Charles Messier included in his famous catalog.  Messier described it as a patch of nebulous light with numerous intertwined stars of different magnitudes. 

The SSSC spans about 1.5 degrees of the sky and provides us with a view of stars that fills a volume of the galaxy extending about 16,000 light years deep.  Like last week’s star cloud the SSSC provides us with an unobscured view into the depths of the Sagittarius arm of the Milky Way.

In light polluted skies where the dim glow of the Milky Way cannot be seen the SSSC looks like a collection of bright stars that are organized into long chains and arches.  All together I think they look like an umbrella that has been turned out by strong winds.  It is a very nice view that contains a number of bright stars many of which are double stars. 

Getting out to a dark site where the dim glow of the Milky Way is visible the SSSC will appear as a detached and brighter portion of the Milky Way.  The SSSC is best viewed through binoculars or small telescopes with wide fields of view.  Larger instruments will typically limit your field of view only allowing you to see small portions of the star cloud.  On a clear night using a good solid tripod it is easy to get lost in the myriad of stars in this dense part of the Milky Way.  Once you have spent some time scanning the star cloud there are a number of smaller deep sky objects to look for in the same part of the sky.  The most obvious will be an open star cluster called NGC 6603.  This 11th magnitude cluster will be a fine target in larger binoculars and small telescopes.  In addition to NGC 6603 you may notice two large dark patches in the SSSC.  These are dark nebulae known as B92 and B93.  These are large clumps of dust that block out the light from background stars.  Beyond these more obvious objects there are a number of less obvious clusters, a number of double stars and a planetary nebula to look for using moderate sized telescopes.  For an object that only spans 1.5 degrees of the sky it is densely packed with loads of goodies that will keep you occupied for a long time. 

To find the SSSC look for the teapot shape of Sagittarius described last week.  Using binoculars scan north of the teapot’s top and you will easily identify the compact dense star field of the SSSC.  Below you will find links to a map that will help you locate this object and additional information about the SSSC.  The linked IAU map for Sagittarius does not label the SSSC (M24) but it is located near a star called Mu Sagitarii.  This star will be marked on the map.

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

http://messier.seds.org/m/m024.html

The star cloud for the week of August 18 is the Scutum Star Cloud (SSC).  Like those covered in the previous weeks the SSC is a relatively dust free window into a deeper portion of the Milky Way.  This window again allows us to peer deeper into the arm of the Milky Way known as the Sagittarius arm. 

To find this part of the Milky Way first locate the three bright stars in the Summer Triangle; Vega, Denib and Altair.  The southern most of the three stars is Altair which is the brightest star in the constellation Aquila the Eagle.  The brightest stars of Aquila take the shape of an elongated diamond with the north/south axis short and the east/west axis long.  If you use binoculars and follow the north/south axis of Aquila’s diamond shape to the south for roughly 10 degrees of sky you will find the star Lambda Aquilae.  Scanning the sky around this star you will see a bright hook shape of stars which demarcates the northern edge of the SSC. 

For observers contending with light pollution that obscures the dim glow of the Milky Way, this hook shape of stars will be the first indicator you are looking at the SSC however most of the bright stars you see in the hook shape are only a few hundred light years away from us.  This means they belong to the same part of the Milky Way the Sun does.  As you scan the sky below the hook shape of stars you will start to notice fainter stars around 7th, 8th and 9th magnitudes.  Many of these fainter stars are giant stars that lie up to 4,000 light years away.  Some of these giant stars are on the nearer edge of our neighboring Sagittarius arm of the galaxy. 

While scanning for these fainter giant stars you will likely notice one or maybe two dim patches of light.  One of them appears near the curve of the hook shape and the other is another five degrees south of the hook shape near the star Delta Scutii.  These dim patches are galactic star clusters known as M11 and M26.  M11 is also known as the Wild Duck Cluster and lies at a distance of about 6,000 light years.  This is a collection of roughly 2,900 stars that are about 220 million years old.  M26 is a little fainter and the member stars are a little more scattered which will make it a tougher cluster to find.  M26 lies about 5,000 light years away and its member stars are a bit over 80 million years old.  Both of these clusters are located in the Sagittarius arm.

Also in the area of the sky covered by the SSC is the classic carbon star V Aquilae.  Carbon stars are usually highly evolved red giant stars that have more carbon than oxygen in their atmospheres.  This allows for carbon compounds to form which are good at scattering light.  The wavelengths that are not affected by this scattering are the red wavelengths so carbon stars appear to be the reddest stars in the sky.  V Aquilae can be found between the stars Lambda and 12 Aquilae.  These are two of the brighter stars in the hook shape.

Getting out to a dark sky site the SSC will appear as one of the brightest parts of the Milky Way.  Scanning this dim glow you will notice several dark patches where clouds of dust obscure parts of the star cloud.  These types of dark dust clouds are called dark nebulae which were cataloged by astronomer Edward Emerson, Barnard.  Barnard’s catalog contains 366 of these dark nebulae many of which can be seen with binoculars on nights with good viewing conditions.  You can find 19 of Barnard’s dark nebulae scattered around the SSC. 

I will include a number constellation maps that are near the SSC to aid in its discovery.  The key will be to find the Summer Triangle and from there it is pretty simple.  Besides the object listed above there is a globular star cluster a planetary nebula and a number of interesting stars in the same vicinity of the SSC.  I would highly recommend using desktop planetarium software such as Stellarium to help you explore this rich part of the sky.

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

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

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

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

Our next Star Party will be held on Friday, September 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 September 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, August 11

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, August 11.  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, September 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 6:11 a.m. on Monday, August 11 and sunset is at 8:00 p.m. providing us with about 14 hours of daylight.  Even after sunset, the light from the Sun will still dimly illuminate our sky for about 1 and one half hours.  This period of time is called twilight, which ends around 9:40 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 1:06 p.m. this week.     

Moonrise for Monday, August 11 occurs at 8:31 p.m.  Moonset will occur at 8:29 a.m. on the following day.  On Monday, August 11 the Moon will be exhibiting a waning gibbous phase with roughly 98% of the lunar disk illuminated.  Last quarter moon occurs on August 17, 2014. 

International Space Station (ISS) Observing

This week visible passes of ISS are evening passes.  The best of these occur on the evenings of August 16, 17 and 18.  To learn more about these passes and others this week use the information below.

Catch ISS flying over St. Louis in evening hours starting Monday, August 11. 

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

12 Aug

-0.3

22:35:20

10

N

22:36:45

12

NNE

22:36:50

12

NNE

13 Aug

-0.2

21:47:07

10

N

21:47:26

10

N

21:47:45

10

NNE

14 Aug

-0.6

22:33:19

10

NNW

22:34:53

17

N

22:34:53

17

N

15 Aug

-0.8

21:44:37

10

NNW

21:46:34

15

NNE

21:47:30

13

NE

16 Aug

-0.5

20:56:01

10

N

20:57:14

12

NNE

20:58:27

10

NE

16 Aug

-0.8

22:31:30

10

NW

22:33:00

22

NNW

22:33:00

22

NNW

17 Aug

-1.6

21:42:38

10

NNW

21:45:29

25

NNE

21:45:39

25

NE

18 Aug

-1.1

20:53:51

10

NNW

20:56:13

18

NNE

20:58:21

11

ENE

18 Aug

-0.7

22:29:55

10

NW

22:31:12

22

WNW

22:31:12

22

WNW

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

Venus

Venus is now well within its current morning apparition. It rises around 4:35 a.m. becoming visible after 5:00 a.m.  Venus is currently exhibiting a gibbous phase with roughly 94% of the Venusian disk illuminated.

Mars

Mars is now in the constellation Libra and rises before the Sun sets.  For those awake around 9:00 p.m. you will see a reddish-orange object high in the southern skies.  We have now passed by Mars in our orbit and will continue to move further away each day.  Mars will set by 11:13 p.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 11:50 p.m.  Saturn can be found near the bright double star Zubenelgenubi.    

Keep an eye on Mars and Saturn as the two are approaching each other in the sky.  Later this year Mars will pass Saturn on its way into the constellation Scorpius. 

2014 Perseid Meteor Shower

It is that time of the year again when the Earth sweeps through debris left by comet 109P/ Swfit/Tuttle leading to one of the most spectacular of the meteor showers called the Perseids.  This meteor shower starts at the end of July and lasts up to the end of August.  Peak activity occurs around the 12th and 13th of August with the most meteors visible after midnight.  Sadly this year will not be a good one for the Perseids as we are only two days after full moon.  This will greatly limit the number of meteors visible.  To observe any meteor shower simply go outside and look up.  It is best to look in the direction of the meteor shower’s radiant which is in the northeast for the Perseids.  Below you will find more information regarding the Perseids and other meteor activity. 

http://amsmeteors.org/

http://spaceweather.com/

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. 

For August we are going to do things a little different again. This month we will visit three constellations that contain an object called a star cloud.  These are virtually dust free windows into the larger structures of the Milky Way.  This type of object is typically missed by those of us that observe from light polluted locations like St. Louis as the dim glow of the Milky Way’s concentration is washed from view.  The constellations we will visit to find these are Sagittarius, Scutum and Cygnus. 

Star clouds are fascinating structures.  Again they are virtually dust free windows into the larger structures of the Milky Way.  A good analogy for this is to imagine an overcast day.  As you scan the cloudy sky you come across a hole in the clouds giving you an unobscured view of the blue sky.  Just like atmospheric clouds obscure the sky behind them, clouds of dust and gas in our galaxy will obscure the stars that are positioned behind them.  Scattered along the dim glow of the Milky Way are relatively dust free zones that offer bright unobscured views of the dense and distant star fields of the Milky Way’s spiral arms.  Even though a great deal of what star clouds offer is lost to observers with light polluted skies they still offer large vistas of denser star fields and often contain some of the most striking deep sky objects to look for.

When observing these large features in the sky it is best to star with binoculars.  They offer a much wider field of view and can take in more of the dense star field.  Once you have done this for a while then try pointing a telescope into the star clouds. This will yield views of more specific objects such as open star clusters, double/multiple stars and various nebulas. 

The first star cloud we will look at is the Great Sagittarius Star Cloud (GSSC).  As the name implies this star cloud is located in the constellation Sagittarius.  This famous constellation can be found in our southern skies during the summer months.  Due to its low altitude Sagittarius may be hard for some to see if you have tall buildings or trees south of your viewing location.  Finding Sagittarius is pretty simple.  First locate a large fishhook shape of stars in the south.  This is the constellation Scorpius.  Just east of the fishhook you will find another bright group of stars in shape of a stovetop teapot.  This is called the teapot asterism which is the bright part of the constellation Sagittarius. 

Once you have found the Teapot asterism grab some binoculars and scan the patch of sky near the spout of the teapot.  Here is where you will find the Great Sagittarius Star Cloud.  For those of us in light polluted skies this part of the sky will have a noticeably denser star field.  The part of the Milky Way we are looking at here is the Sagittarius arm of the galaxy that sits between us and the center of our galaxy.  Many of the stars you will be able to see in binoculars lie at distances between 6,500 and 13,000 lights years away.  Even in light polluted skies there are thousands of stars scattered in this relatively small patch of sky. 

Getting out to dark skies is where you will see why these structures are called star clouds.  With just the unaided eye the dense fields of these relatively dust free windows into the depths of the Milky Way will be much brighter than the rest of the dust obscured parts of our galaxy’s concentration.  The glow you see here is representative of millions of stars that lie closer to the Milky Way’s core than we do. 

Once you have scanned and taken in the entire star cloud there are a number of other objects that stand out in the same area.  M7 or Ptolemy’s cluster is an open cluster that is much closer to us than the GSSC is.  It will be easily seen as a bright group of roughly 80 stars on the southern boundary of the star cloud.  At only 800 light years away this group of stars is in the same arm (Orion Spur) of the galaxy that the Sun is.  On the north edge of the GSSC is a bright emission nebula called M8 or the Lagoon Nebula.  This is an area where stars are actively forming that lies at about 5,200 light years away.  This stellar nursery is part of the Sagittarius arm of our galaxy and can be easily spotted with small binoculars.  In fact if you scan north of M8 you will find three more nebulae that are also in the Sagittarius arm.  These are named M20, M17 and M16. 

In addition to these nebulae there are a number of open star clusters scatter around the GSSC that can be seen but many will go unnoticed if you just quickly scan through the sky.  Most of the cluster will be around 8th or 9th magnitude and contain fewer than 100 stars. 

To get as much out of the GSSC you will need to spend some quality time soaking in the light for these distant stars.  I would recommend starting with binoculars no larger than 10 x 50.  There will be numerous double stars to identify and a hand full of deep sky objects as well.  Having a desktop planetarium software handy will help you identify some of these but a more detailed database will be required for fainter less obvious objects.  Below you will find basic maps of Sagittarius and Scorpius that will aid you in finding the GSSC and the brighter deep sky objects listed above. 

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

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

The star cloud for August 11 is called the Small Sagittarius Star Cloud (SSSC).  Even though the name implies it is lesser in nature this is the densest and my favorite of the star clouds we will look at this month.  The SSSC is also known as M24 as it was one of the objects Charles Messier included in his famous catalog.  Messier described it as a patch of nebulous light with numerous intertwined stars of different magnitudes. 

The SSSC spans about 1.5 degrees of the sky and provides us with a view of stars that fills a volume of the galaxy extending about 16,000 light years deep.  Like last week’s star cloud the SSSC provides us with an unobscured view into the depths of the Sagittarius arm of the Milky Way.

In light polluted skies where the dim glow of the Milky Way cannot be seen the SSSC looks like a collection of bright stars that are organized into long chains and arches.  All together I think they look like an umbrella that has been turned out by strong winds.  It is a very nice view that contains a number of bright stars many of which are double stars. 

Getting out to a dark site where the dim glow of the Milky Way is visible the SSSC will appear as a detached and brighter portion of the Milky Way.  The SSSC is best viewed through binoculars or small telescopes with wide fields of view.  Larger instruments will typically limit your field of view only allowing you to see small portions of the star cloud.  On a clear night using a good solid tripod it is easy to get lost in the myriad of stars in this dense part of the Milky Way.  Once you have spent some time scanning the star cloud there are a number of smaller deep sky objects to look for in the same part of the sky.  The most obvious will be an open star cluster called NGC 6603.  This 11th magnitude cluster will be a fine target in larger binoculars and small telescopes.  In addition to NGC 6603 you may notice two large dark patches in the SSSC.  These are dark nebulae known as B92 and B93.  These are large clumps of dust that block out the light from background stars.  Beyond these more obvious objects there are a number of less obvious clusters, a number of double stars and a planetary nebula to look for using moderate sized telescopes.  For an object that only spans 1.5 degrees of the sky it is densely packed with loads of goodies that will keep you occupied for a long time. 

To find the SSSC look for the teapot shape of Sagittarius described last week.  Using binoculars scan north of the teapot’s top and you will easily identify the compact dense star field of the SSSC.  Below you will find links to a map that will help you locate this object and additional information about the SSSC.  The linked IAU map for Sagittarius does not label the SSSC (M24) but it is located near a star called Mu Sagitarii.  This star will be marked on the map.

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

http://messier.seds.org/m/m024.html       

Our next Star Party will be held on Friday, September 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 September 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, July 28

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, July 28.  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, August 1, 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 5:59 a.m. on Monday, July 28 and sunset is at 8:15 p.m. providing us with about 14 and one half hours of daylight.  Even after sunset, the light from the Sun will still dimly illuminate our sky for about 2 hours.  This period of time is called twilight, which ends around 10:02 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 1:08 p.m. this week.   

Moonrise for Monday, July 28 occurs at 7:39 a.m.  Moonset will occur at 8:59 p.m.  On Monday, July 28 the Moon will be exhibiting a waxing crescent phase with roughly 3% of the lunar disk illuminated.  First qaurter moon occurs on August 3 this week at 7:50 p.m.      

International Space Station (ISS) Observing

This week visible passes of ISS will be in the early morning and evening hours.  The best of these will occur on August 1 and 3.  To learn more about this pass and others this week use the information below.

Catch ISS flying over St. Louis in the morning and evening hours starting Monday, July 28. 

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

30 Jul

-0.9

05:09:15

10

NNW

05:12:09

26

NNE

05:15:03

10

E

31 Jul

-0.3

04:20:42

10

NNW

04:23:10

19

NNE

04:25:38

10

ENE

01 Aug

-2.7

05:08:02

10

NW

05:11:22

64

NE

05:14:42

10

ESE

01 Aug

-1.3

21:49:20

10

SSW

21:50:19

18

SSW

21:50:19

18

SSW

02 Aug

-1.7

04:19:20

10

NW

04:22:29

37

NNE

04:25:38

10

ESE

02 Aug

-2.1

21:01:05

10

S

21:03:47

23

SE

21:06:31

10

ENE

02 Aug

-1.7

22:37:16

10

W

22:40:22

35

NNW

22:41:14

30

N

03 Aug

-0.9

03:30:42

10

NNW

03:33:32

24

NNE

03:36:21

10

E

03 Aug

-2.9

05:07:10

10

WNW

05:10:21

41

SW

05:13:31

10

SSE

03 Aug

-2.8

21:48:11

10

WSW

21:51:29

60

NW

21:54:47

10

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

Venus

Venus is now well within its current morning apparition. It rises around 4:09 a.m. becoming easily visible by 4:40 a.m.  Venus is currently exhibiting a gibbous phase with roughly 60% of the Venusian disk illuminated.

Mars

Mars is now in the constellation Virgo and rises before the Sun sets.  For those awake around 9:00 p.m. you will see a reddish-orange object high in the southern skies.  We have now passed by Mars in our orbit and will continue to move further away each day.  Mars will set by 11:47 p.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 12:48 a.m.  Saturn can found near the bright double star Zubenelgenubi.    

Keep an eye on Mars and Saturn as the two are approaching each other in the sky.  Later this year Mars will pass Saturn on its way into the constellation Scorpius. 

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. 

For July will explore objects in the constellation called Lyra the Harp.  This constellation is one of those that are part of the bright asterism known as the Summer Triangle.  It contains the bright star Vega which is one of the three stars that make the bright triangle.  The Summer Triangle acts as a beacon for observers during the summer months helping us find other constellations and the objects they contain.  Due to the visibility and usefulness of the triangle, the constellation Lyra is one of the first visited by many observers during the summer months. 

The ancient Greeks imagined this small bright grouping of stars as the lyre that Apollo gave to his son Orpheus.  After the death of his wife Eurydice, Orpheus played his lyre impressing Hyades the god of the underworld.  Hyades was so impressed that he allowed Eurydice to follow Orpheus out of the underworld provided that Orpheus not turn back and look at her until they were safely out.  Orpheus at the last minute could not resist and when he turned back to look she was gone forever.

Lyra is also the home of one of the best meteor showers we see every year.  The Lyrid meteor shower is caused as the Earth annually plows through debris left by Comet Thatcher.  The first recorded observation of this meteor shower dates back to 687 BCE when Chinese astronomers recorded what appeared to be stars falling out of the sky in April.  April is the peak month to view the Lyrids with a peak date of April 22.

http://meteorshowersonline.com/lyrids.html

The crown jewel of Lyra is the bright star Vega.  This beautiful star is an A-class star meaning it will appear blue white in color.  The temperature of Vega is about 9,600 Kelvin making it about 1.7 times hotter than the Sun.  It is only twice the mass of the Sun but because of its higher temperature it is about 40 times more luminous.  This makes Vega one of the most luminous stars in the Sun’s galactic neighborhood.  As Vega is more massive and hotter it will only exist about one tenth as long as the Sun.  That is the nature of the bigger and brighter stars. 

One interesting feature of Vega is its location along the path that the Earth’s northern axis follows during the precession of the equinoxes.  This process is caused because of the Earth’s oblate shape and the tidal forces applied to our planet by the Sun and Moon.  As a result of these two factors the Earth wobbles causing our axis to trace out a cone shape.  This changing orientation causes the north polar axis to be orientated towards different stars.  We do not have to worry about a changing North Star as the precession process takes 26,000 years to complete one full wobble.  This equates to about one degree of motion per year.  In about 12,000 years Vega will become the Earth’s North Star. 

To find Lyra and its crown jewel all you have to do is look east about 45 minutes after sunset.  Doing this you will see three bright stars which form the Summer Triangle asterism mentioned above.  The other two stars in the triangle are called Denib and Altair.  As twilight begins to fade you will notice a parallelogram shape of stars just below Vega.  This is the main pattern people use to identify Lyra the Harp. 

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

The first object we will cover in Lyra is the beautiful planetary nebula called M57 or the Ring Nebula.  Planetary nebulae are the remnants of stars like the Sun as they begin to evolve.  The Sun and all stars start out fusing the hydrogen at their cores.  From this process atoms of helium are produced along with some energy which eventually becomes the light we see emitted by stars.  Like our cars or any device that consumes a material component it will eventually run out of this “fuel” source.  Once the Sun runs out of its core hydrogen its core will begin to collapse and the outer layers will expand and cool.  Due to its collapse core temperature will rise until the helium that has been collecting at the core begins to fuse.  Again the core will run out of its “fuel” and collapses until it is hot enough that carbon and oxygen can fuse.  This stage is called a white dwarf and it is where most stars will end their stellar lives. At this stage all that is left is a much smaller but hotter core.  For a brief time this high temperature allows the dying star to excite the gasses around it creating a beautiful fluorescing cloud of gas and debris.  This is what is called a planetary nebula.  When we observe M57 we are looking at the Sun’s distant future. 

To find M57 first locate the star Vega and the parallelogram shape below it.  Once you have identified the parallelogram shape of stars you need to identify the two southern most stars in this shape.  They are named Beta and Gamma Lyrae.  Using a telescope scan between these two stars and you will find a distinct ring shaped source of light.  This is the planetary nebula M57. 

M57 shines with a magnitude of 8.8 which means it is dim enough that we do need a telescope to observe it.  It is possible that big binoculars will spot it but M57 is roughly one arc minute across causing it to appear very small through wide field devices.  Because of this giant binoculars that have the resolving power to see this nebula would only reveal a small star like object.  If you do not have your own telescope, look up your local astronomy clubs.  Astronomy clubs, museums and many universities will host observing nights that are free to anyone.  Here in St. Louis we have three active astronomy clubs.  All three of them host numerous observing nights one of which is our First Friday observing program.  Below you will find links to the astronomy clubs in St. Louis and more information about M57.

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

http://messier.seds.org/m/m057.html

http://www.slasonline.org/

http://www.asemonline.org/

http://stemideas.org/outreach-projects/star-gazing/

The object for the week of July 7 is the star Delta Lyrae.  There are a few reasons I wanted to cover this star in the night sky update.  First it is a double star.  Unlike those in the past this double is not physically a pair but rather is called an optical double.  These two stars happen to appear close together but are actually about 200 light years apart.  Frequently you will see them listed as Delta-1 and Delta-2.  Delta-1 is a bright B-Class hydrogen fusing star that has a temperature of 18,000 Kelvins.  This puts Delta-1 at nearly 3000 times hotter than the Sun.  Delta-2 is about 200 light years closer to us and is an M-Class red giant star.  Delta-2 is about 7 times more massive than the Sun and is about 300 times larger than the Sun. 

The bright red color of Delta-2 and the blue color of Delta-1 give the pair a very nice color contrast making them an attractive pair to seek out.  In addition to the color contrast Delta-1 is a member of an open star cluster called Stephenson 1.  This is a cluster that is not very well detached from the background stars and it has less than 50 component stars. 

In addition to Delta-1 & 2 you can also try to find another red star called SAO 67546.  This is another member of the Stephenson 1 cluster that is a K-class red giant star that will have an orange hue.  Both Delta-2 and SAO 67546 are stars on their way to becoming white dwarfs that could produce planetary nebulae like M57 discussed last week. 

To find the optical double star Delta Lyrae and the associated Stephenson 1 star cluster first find the bright star Vega.  Once you have identified Vega look for the parallelogram shape of stars below the bright star described last week.  This time we want to use the northern two stars of the parallelogram shape.  These stars are called Zeta and Delta Lyrae.  The latter of the two being our target star. 

Those with sharp vision will be able to determine that Delta Lyrae is two stars.  The distinct color of the two stars and the Stephenson 1 cluster can be seen clearly through a simple pair of binoculars.  The best view of the cluster will be through a telescope using a low magnification eyepiece.  Reference the map linked below for help finding Delta Lyrae and the associated Stephenson 1 star cluster.

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

The object for the week of July 14 is the multiple star system Epsilon Lyrae.  What looks to be a 4th magnitude star near Vega is really the combined glow of four separate stars.  Last week we covered a similar multiple star called Beta Lyrae but Epsilon is different in that its member stars are gravitationally bound to one another.  In other words Epsilon Lyrae is a binary system.  Careful inspection of Epsilon Lyrae will reveal two stars using just your eyes.  For those of us with less than perfect vision a pair of binoculars will plainly reveal what looks like two bright white stars.  The western of the two is Epsilon 1 and the eastern of the two is Epsilon 2.  Epsilon 1 and 2 are separated by roughly 10,000 AU (AU = 93 million miles; average distance between Earth and Sun) and are estimated to take nearly 400,000 years to orbit each other. 

Using a decent telescope at moderate magnification Epsilon 1 and 2 can each be split into two stars.  Splitting Epsilon 1 and 2 is easy because they are about 200 seconds of ac apart.  Splitting the two pairs is a bit more difficult because they are only a few second of arc apart.  A moderate sized telescope will work you will just have to bump up the magnification.  The Epsilon 1 pair is labeled 1A and 1B and the Epsilon 2 pair is labeled 2C and 2D.

All four stars are A-class stars with temperatures that range from 7700 kelvins to 8200 kelvins.  At these temperatures the stars shine with a white to bluish white color.  The stars have masses at 1.9, 1.5, 1.9 and 1.8 solar masses making them main sequence white dwarf stars. These are not the same as the white dwarf discussed above with M57.  The white dwarf related to M57 is a highly evolved star that has shed its outer layers revealing a small dense core that is fusing carbon and oxygen.  Main sequence white dwarfs are young hydrogen fusing stars that are still in their prime.

The stars in the Epsilon Lyrae system are approximately 800 million years old.  For the time being they are gravitationally bound but as they move through the Milky Way the pairs will likely separate into two separate double star systems.  Finding Epsilon Lyrae is pretty simple as it is right next to the bright star Vega.  Once you find Vega all you have to do is look about 2 degrees to the east and you will see Epsilon Lyrae.  If you deal with light pollution or diminished vision you will likely need binoculars to spilt the wide pair.  To spot all four stars you will need a telescope.  Depending on how large your telescope is you will need moderate to high magnification to split all four.  If you have an interest in finding more double or multiple star systems there are numerous other options this time of year.  Sky and Telescope has some very nice articles that will help you find many more doubles and more importantly help you refine your observing skills that are required to find and observe this type of object.  Below you will find links to these articles and the IAU map of Lyra.

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

http://www.skyandtelescope.com/observing/celestial-objects-to-watch/double-stars/  

The object for the week of July 21 is the globular star cluster Messier 56 (M56).  This globular star cluster is a member of the Milky Way’s outer halo of globular star clusters.  It was likely captured by the Milky Way as it consumed one of its dwarf galaxies.  M56 lies about 32,900 light years away from us and is moving towards us at a rate of 145 km/s.  M56 likely has around 50,000 stars as its mass is thought to be 230,000 times that of the Sun.  The stars in M56 are estimated to be about 13.7 billion years old.  Stars this old started to form shortly after the universe expanded into its current state.

At magnitude 8.3 it is one of the fainter globular star clusters included in the Messier catalog.  Even so it can be seen through 50mm binoculars or small aperture telescopes.  When viewed through these instruments M56 will appear as a faint out of focus star.  If you are having trouble seeing the faint glow from these stars try slightly moving your instrument back and forth and this will often help the eye detect the faint light.  Telescopes that are 8 inches or larger will begin to resolve the brightest stars in M56.

Finding M56 is relatively simple as it lays between the two bright stars Gamma Lyrae and the famous double star Alberio in Cygnus the Swan.  If you start at Gamma Lyrae and head towards Alberio you will find an arrow shaped group of stars that will point you towards M56.  M56 is about half way between the two bright stars listed above. 

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

http://messier.seds.org/m/m056.html

The final object we will cover in July is the star Beta Lyrae.  Also known as Sheliak this is normally a 3.52 magnitude star that has a B-spectral class making it blue in color.  It is about 90 times brighter than the Sun and is about 13 times more massive.  Sheliak lies about 960 light years away.

Sheliak is interesting for a number of reasons.  It is a multiple star system, it changes its brightness making it a variable star and it is one of the more distant bright stars we can easily see with the naked eye.  There are many reasons to observe this star but its variable nature is the primary reason.  Sheliak is an eclipsing binary system.  It has two stars that happen to orbit in such a way that their orbital plane is nearly parallel to our line of sight.  Simply put they pass in front of one another.  This happens on a cycle of roughly 13 days.  At about 3 days into the cycle the secondary star eclipses the primary.  By about day 10 the primary will eclipse the secondary.  The first eclipse that occurs is the most dramatic dropping the magnitude of Sheliak by about one order of magnitude.  The secondary eclipse only drops the magnitude of Sheliak by about half a magnitude order. 

The primary eclipse is more dramatic due to the secondary star being larger and it contains an accretion disk.  The disk is comprised of material that it has stolen from its now smaller companion.  At one point the primary star in this pair was the more massive and larger of the two.  It started to evolve into a giant star allowing it to exceed its Roche Lobe.  When a star fills its Roche lobe, material gravitationally bound to the star can escape out into space or in the case of a binary system can transfer to the partner star leading to an accretion disk.

When all is said and done roughly every 13 days you will notice Sheliak dim down to about 4.3.  Sheliak will slowly dim down to its minimum magnitude of 4.3 which occurs on day three of the cycle.  It will take another three days to reach it maximum magnitude of 3.4.  The three day cycle continues bringing Sheliak’s magnitude down to about 3.8 magnitude for the lesser eclipse and then back up again three days later.  Tracking variable stars can be a challenge but as long as you establish some reference stars this variable should be pretty easy for most to follow. 

To find Sheliak locate Vega.  Below it you will find the parallelogram shape of stars discussed in previous weeks.  The southern and eastern most of the four stars in the parallelogram shape is the star Sheliak.  Every night over a period of about 13 days go outside once twilight has ended and make an estimate for Sheliak’s magnitude.  If you do this often enough it will become easy to identify the maximum and minimum for this bright star.  Reference the links below to learn more about this star.

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

http://www.aavso.org/vsots_betalyr

Our next Star Party will be held on Friday, August 1, 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 August 1, 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, July 21

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, July 21.  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, August 1, 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 5:53 a.m. on Monday, July 21 and sunset is at 8:21 p.m. providing us with about 14 and one half hours of daylight.  Even after sunset, the light from the Sun will still dimly illuminate our sky for about 2 hours.  This period of time is called twilight, which ends around 10:11 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 1:07 p.m. this week.     

Moonrise for Monday, July 21 occurs at 1:44 a.m.  Moonset will occur at 4:04 p.m.  On Monday, July 21 the Moon will be exhibiting a waning crescent phase with roughly 24% of the lunar disk illuminated.  New moon occurs on July 26 this week at 5:42 p.m.      

International Space Station (ISS) Observing

This week visible passes of ISS will be in the early morning hours.  The best of these will occur on July 22 and 23.  To learn more about this pass and others this week use the information below.

Catch ISS flying over St. Louis in the morning starting Monday, July 21. 

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

22 Jul

-1.7

03:35:25

27

NW

03:35:39

28

NNW

03:38:37

10

NNE

22 Jul

-0.2

05:12:46

10

NNW

05:13:18

10

N

05:13:50

10

N

23 Jul

-1.0

02:48:35

25

NNE

02:48:35

25

NNE

02:50:17

10

NE

23 Jul

-0.4

04:23:02

10

NW

04:24:29

12

NNW

04:25:56

10

N

24 Jul

 0.1

02:01:44

11

NE

02:01:44

11

NE

02:01:52

10

NE

24 Jul

-0.7

03:34:36

14

NW

03:35:42

15

NNW

03:37:48

10

NNE

25 Jul

-0.7

02:47:43

19

N

02:47:43

19

N

02:49:35

10

NNE

26 Jul

 0.1

02:00:49

13

NNE

02:00:49

13

NNE

02:01:18

10

NNE

26 Jul

-0.1

03:35:11

10

NNW

03:35:54

11

N

03:36:36

10

N

27 Jul

-0.2

02:46:46

13

NNW

02:47:04

13

NNW

02:48:37

10

NNE

28 Jul

 0.1

01:59:50

13

N

01:59:50

13

N

02:00:27

10

NNE

28 Jul

-0.2

05:12:02

10

NNW

05:14:05

15

NNE

05:16:09

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

Venus

Venus is now well within its current morning apparition. It rises around 4:00 a.m. becoming easily visible by 4:30 a.m.  Venus is currently exhibiting a gibbous phase with roughly 60% of the Venusian disk illuminated.

Mars

Mars is now in the constellation Virgo and rises before the Sun sets.  For those awake around 9:00 p.m. you will see a reddish-orange object high in the southern skies.  We have now passed by Mars in our orbit and will continue to move further away each day.  Mars will set by 12:09 a.m. 

Saturn

Saturn has reached opposition and thus will rise before the sun sets.  Look for it in the southeast about 30 minutes to an hour after sunset depending on how clear your southeastern skies are.  Saturn will remain with us until 1:16 a.m.  It forms a nice triangle in the sky with Libra’s two brightest stars Zubenelgenubi and Zubeneschamali. 

If you watch Saturn in relation to these two stars you will notice it is exhibiting retrograde motion.  This is caused as the Earth catches up with a planet and then passes it by.  During this we see the planet from changing angles making it appear to move westward and then eastward again. This motion is more prevalent with planets closer to us such as Mars.  If you go outside once a week for the rest of the year and sketch where Saturn is in relation to Zubenelgenubi and Zubeneschamli you will see this retrograde motion. 

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. 

For July will explore objects in the constellation called Lyra the Harp.  This constellation is one of those that are part of the bright asterism known as the Summer Triangle.  It contains the bright star Vega which is one of the three stars that make the bright triangle.  The Summer Triangle acts as a beacon for observers during the summer months helping us find other constellations and the objects they contain.  Due to the visibility and usefulness of the triangle, the constellation Lyra is one of the first visited by many observers during the summer months. 

The ancient Greeks imagined this small bright grouping of stars as the lyre that Apollo gave to his son Orpheus.  After the death of his wife Eurydice, Orpheus played his lyre impressing Hyades the god of the underworld.  Hyades was so impressed that he allowed Eurydice to follow Orpheus out of the underworld provided that Orpheus not turn back and look at her until they were safely out.  Orpheus at the last minute could not resist and when he turned back to look she was gone forever.

Lyra is also the home of one of the best meteor showers we see every year.  The Lyrid meteor shower is caused as the Earth annually plows through debris left by Comet Thatcher.  The first recorded observation of this meteor shower dates back to 687 BCE when Chinese astronomers recorded what appeared to be stars falling out of the sky in April.  April is the peak month to view the Lyrids with a peak date of April 22.

http://meteorshowersonline.com/lyrids.html

The crown jewel of Lyra is the bright star Vega.  This beautiful star is an A-class star meaning it will appear blue white in color.  The temperature of Vega is about 9,600 Kelvin making it about 1.7 times hotter than the Sun.  It is only twice the mass of the Sun but because of its higher temperature it is about 40 times more luminous.  This makes Vega one of the most luminous stars in the Sun’s galactic neighborhood.  As Vega is more massive and hotter it will only exist about one tenth as long as the Sun.  That is the nature of the bigger and brighter stars. 

One interesting feature of Vega is its location along the path that the Earth’s northern axis follows during the precession of the equinoxes.  This process is caused because of the Earth’s oblate shape and the tidal forces applied to our planet by the Sun and Moon.  As a result of these two factors the Earth wobbles causing our axis to trace out a cone shape.  This changing orientation causes the north polar axis to be orientated towards different stars.  We do not have to worry about a changing North Star as the precession process takes 26,000 years to complete one full wobble.  This equates to about one degree of motion per year.  In about 12,000 years Vega will become the Earth’s North Star. 

To find Lyra and its crown jewel all you have to do is look east about 45 minutes after sunset.  Doing this you will see three bright stars which form the Summer Triangle asterism mentioned above.  The other two stars in the triangle are called Denib and Altair.  As twilight begins to fade you will notice a parallelogram shape of stars just below Vega.  This is the main pattern people use to identify Lyra the Harp. 

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

The first object we will cover in Lyra is the beautiful planetary nebula called M57 or the Ring Nebula.  Planetary nebulae are the remnants of stars like the Sun as they begin to evolve.  The Sun and all stars start out fusing the hydrogen at their cores.  From this process atoms of helium are produced along with some energy which eventually becomes the light we see emitted by stars.  Like our cars or any device that consumes a material component it will eventually run out of this “fuel” source.  Once the Sun runs out of its core hydrogen its core will begin to collapse and the outer layers will expand and cool.  Due to its collapse core temperature will rise until the helium that has been collecting at the core begins to fuse.  Again the core will run out of its “fuel” and collapses until it is hot enough that carbon and oxygen can fuse.  This stage is called a white dwarf and it is where most stars will end their stellar lives. At this stage all that is left is a much smaller but hotter core.  For a brief time this high temperature allows the dying star to excite the gasses around it creating a beautiful fluorescing cloud of gas and debris.  This is what is called a planetary nebula.  When we observe M57 we are looking at the Sun’s distant future. 

To find M57 first locate the star Vega and the parallelogram shape below it.  Once you have identified the parallelogram shape of stars you need to identify the two southern most stars in this shape.  They are named Beta and Gamma Lyrae.  Using a telescope scan between these two stars and you will find a distinct ring shaped source of light.  This is the planetary nebula M57. 

M57 shines with a magnitude of 8.8 which means it is dim enough that we do need a telescope to observe it.  It is possible that big binoculars will spot it but M57 is roughly one arc minute across causing it to appear very small through wide field devices.  Because of this giant binoculars that have the resolving power to see this nebula would only reveal a small star like object.  If you do not have your own telescope, look up your local astronomy clubs.  Astronomy clubs, museums and many universities will host observing nights that are free to anyone.  Here in St. Louis we have three active astronomy clubs.  All three of them host numerous observing nights one of which is our First Friday observing program.  Below you will find links to the astronomy clubs in St. Louis and more information about M57.

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

http://messier.seds.org/m/m057.html

http://www.slasonline.org/

http://www.asemonline.org/

http://stemideas.org/outreach-projects/star-gazing/

The object for the week of July 7 is the star Delta Lyrae.  There are a few reasons I wanted to cover this star in the night sky update.  First it is a double star.  Unlike those in the past this double is not physically a pair but rather is called an optical double.  These two stars happen to appear close together but are actually about 200 light years apart.  Frequently you will see them listed as Delta-1 and Delta-2.  Delta-1 is a bright B-Class hydrogen fusing star that has a temperature of 18,000 Kelvins.  This puts Delta-1 at nearly 3000 times hotter than the Sun.  Delta-2 is about 200 light years closer to us and is an M-Class red giant star.  Delta-2 is about 7 times more massive than the Sun and is about 300 times larger than the Sun. 

The bright red color of Delta-2 and the blue color of Delta-1 give the pair a very nice color contrast making them an attractive pair to seek out.  In addition to the color contrast Delta-1 is a member of an open star cluster called Stephenson 1.  This is a cluster that is not very well detached from the background stars and it has less than 50 component stars. 

In addition to Delta-1 & 2 you can also try to find another red star called SAO 67546.  This is another member of the Stephenson 1 cluster that is a K-class red giant star that will have an orange hue.  Both Delta-2 and SAO 67546 are stars on their way to becoming white dwarfs that could produce planetary nebulae like M57 discussed last week.  

To find the optical double star Delta Lyrae and the associated Stephenson 1 star cluster first find the bright star Vega.  Once you have identified Vega look for the parallelogram shape of stars below the bright star described last week.  This time we want to use the northern two stars of the parallelogram shape.  These stars are called Zeta and Delta Lyrae.  The latter of the two being our target star. 

Those with sharp vision will be able to determine that Delta Lyrae is two stars.  The distinct color of the two stars and the Stephenson 1 cluster can be seen clearly through a simple pair of binoculars.  The best view of the cluster will be through a telescope using a low magnification eyepiece.  Reference the map linked below for help finding Delta Lyrae and the associated Stephenson 1 star cluster.

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

The object for the week of July 14 is the multiple star system Epsilon Lyrae.  What looks to be a 4th magnitude star near Vega is really the combined glow of four separate stars.  Last week we covered a similar multiple star called Beta Lyrae but Epsilon is different in that its member stars are gravitationally bound to one another.  In other words Epsilon Lyrae is a binary system.  Careful inspection of Epsilon Lyrae will reveal two stars using just your eyes.  For those of us with less than perfect vision a pair of binoculars will plainly reveal what looks like two bright white stars.  The western of the two is Epsilon 1 and the eastern of the two is Epsilon 2.  Epsilon 1 and 2 are separated by roughly 10,000 AU (AU = 93 million miles; average distance between Earth and Sun) and are estimated to take nearly 400,000 years to orbit each other. 

Using a decent telescope at moderate magnification Epsilon 1 and 2 can each be split into two stars.  Splitting Epsilon 1 and 2 is easy because they are about 200 seconds of ac apart.  Splitting the two pairs is a bit more difficult because they are only a few second of arc apart.  A moderate sized telescope will work you will just have to bump up the magnification.  The Epsilon 1 pair is labeled 1A and 1B and the Epsilon 2 pair is labeled 2C and 2D.

All four stars are A-class stars with temperatures that range from 7700 kelvins to 8200 kelvins.  At these temperatures the stars shine with a white to bluish white color.  The stars have masses at 1.9, 1.5, 1.9 and 1.8 solar masses making them main sequence white dwarf stars. These are not the same as the white dwarf discussed above with M57.  The white dwarf related to M57 is a highly evolved star that has shed its outer layers revealing a small dense core that is fusing carbon and oxygen.  Main sequence white dwarfs are young hydrogen fusing stars that are still in their prime.

The stars in the Epsilon Lyrae system are approximately 800 million years old.  For the time being they are gravitationally bound but as they move through the Milky Way the pairs will likely separate into two separate double star systems.  Finding Epsilon Lyrae is pretty simple as it is right next to the bright star Vega.  Once you find Vega all you have to do is look about 2 degrees to the east and you will see Epsilon Lyrae.  If you deal with light pollution or diminished vision you will likely need binoculars to spilt the wide pair.  To spot all four stars you will need a telescope.  Depending on how large your telescope is you will need moderate to high magnification to split all four.  If you have an interest in finding more double or multiple star systems there are numerous other options this time of year.  Sky and Telescope has some very nice articles that will help you find many more doubles and more importantly help you refine your observing skills that are required to find and observe this type of object.  Below you will find links to these articles and the IAU map of Lyra.

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

http://www.skyandtelescope.com/observing/celestial-objects-to-watch/double-stars/  

The object for the week of July 21 is the globular star cluster Messier 56 (M56).  This globular star cluster is a member of the Milky Way’s outer halo of globular star clusters.  It was likely captured by the Milky Way as it consumed one of its dwarf galaxies.  M56 lies about 32,900 light years away from us and is moving towards us at a rate of 145 km/s.  M56 likely has around 50,000 stars as its mass is thought to be 230,000 times that of the Sun.  The stars in M56 are estimated to be about 13.7 billion years old.  Stars this old started to form shortly after the universe expanded into its current state.

At magnitude 8.3 it is one of the fainter globular star clusters included in the Messier catalog.  Even so it can be seen through 50mm binoculars or small aperture telescopes.  When viewed through these instruments M56 will appear as a faint out of focus star.  If you are having trouble seeing the faint glow from these stars try slightly moving your instrument back and forth and this will often help the eye detect the faint light.  Telescopes that are 8 inches or larger will begin to resolve the brightest stars in M56.

Finding M56 is relatively simple as it lays between the two bright stars Gamma Lyrae and the famous double star Alberio in Cygnus the Swan.  If you start at Gamma Lyrae and head towards Alberio you will find an arrow shaped group of stars that will point you towards M56.  M56 is about half way between the two bright stars listed above. 

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

http://messier.seds.org/m/m056.html

Our next Star Party will be held on Friday, August 1, 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 August 1, 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

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