NIGHT SKY UPDATE for the week of Monday, October 19

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, October 19.  All times are given as local St. Louis time (Central Daylight Time).  For definitions of terminology used in the night sky update, click the highlighted text. 

Information updated weekly or as needed. 

Join us for our next star party, Friday, November 6, 2015 held in association with the St. Louis Astronomical Society.  For details, see the information at the bottom of this page. 

The Sun and the Moon 

Sunrise is at 7:14 a.m. on Monday, October 19 and sunset is at 6:17 p.m. providing us with about 11 hours of daylight.  Even after sunset, the light from the Sun will still dimly illuminate our sky for about 1.5 hours.  This period of time is called twilight, which ends around 7:46 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 12:46 p.m. this week.   

Day

Sunrise

Sunset

19 Oct

7:14 a.m.

6:17 p.m.

20 Oct

7:15 a.m.

6:16 p.m.

 21 Oct

7:16 a.m.

6:15 p.m.

 22 Oct

7:17 a.m.

6:13 p.m.

 23 Oct

7:18 a.m.

6:12 p.m.

 24 Oct

7:19 a.m.

6:11 p.m.

 25 Oct

7:20 a.m.

6:10 p.m.

 26 Oct

7:21 a.m.

6:08 p.m.

 27 Oct

7:22 a.m.

6:07 p.m.

           

Moonrise for Monday, October 19 occurs at 1:02 p.m. and moonset will occur at 11:26 p.m.  On Monday, October 19 the lunar phase will be a waxing crescent moon with roughly 38% of the Moon’s visible disk illuminated.  First quarter moon occurs on Tuesday, October 20.       

International Space Station (ISS) Observing 

Visible passes of ISS this week over St. Louis are in the evening hours.  The best of these occur on the evenings of October 21 and 24.  For information about these passes and others use the table below. 

Catch ISS flying over St. Louis in the evening hours starting Monday, October 19.  

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

20 Oct

-1.7

18:53:43

10

NNW

18:56:15

20

NNE

18:58:21

12

ENE

20 Oct

-0.7

20:29:44

10

WNW

20:31:00

21

WNW

20:31:00

21

WNW

21 Oct

-3.5

19:37:07

10

NW

19:40:22

75

NE

19:40:53

57

ESE

22 Oct

-2.7

18:44:37

10

NW

18:47:42

38

NNE

18:50:46

10

ESE

22 Oct

-0.8

20:21:30

10

W

20:23:36

20

WSW

20:23:36

20

WSW

23 Oct

-2.1

19:28:23

10

WNW

19:31:29

40

SW

19:33:49

15

SSE

24 Oct

-3.3

18:35:37

10

NW

18:38:52

88

SW

18:42:07

10

SE

25 Oct

-0.4

19:20:12

10

W

19:22:21

16

SW

19:24:26

10

S  

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

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

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

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

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

http://www.jpl.nasa.gov/ 

The Planets Visible Without A Telescope

Mercury

The nearest planet to the Sun is visible shortly before the Sun rises.  Mercury rises as 5:50 a.m. and will be visible by about 6:20 a.m. about 8 degrees above the eastern horizon.  To see Mercury you will have to find an observing location in which the eastern horizon if free of any obstructions.     

Venus

Venus is again visible in the morning hours just before sunrise.  Venus rises at 3:29 a.m.  You can see it paired with Mars and Jupiter low in the east around 5:00 a.m. 

Mars

The Red planet is now climbing out of the Sun’s glare rising at 3:48 a.m.  By 5:00 a.m. Mars will be easily seen together with Jupiter and Venus.  Mars will be the dimmer of the three planets as it is currently shining with an apparent magnitude of 1.8.  Mars will continue to climb higher in our sky as we approach May 22, 2016 which is the next Opposition of Mars.  Mars is back and getting better once again.  

Jupiter

The largest planet in the solar system is out of the Sun’s glare rising at 3:48 a.m. To see Jupiter you will have to look east at about 5:00 a.m.  Jupiter will rise about 30 minutes earlier each week than it did the week before.      

Saturn

Saturn is reaching the end of another apparition.  Due to the angle of the ecliptic Saturn will remain low in the southwestern sky.  Look for the ringed planet about 40 minutes after sunset low in the southwest.  Saturn will set by 8:04 p.m.    

Orionid Meteor Shower

This week sees the peak of the Orionid meteor shower.  It will peak on October 21/22 with the best views occurring after midnight on the 22nd.  The Orionids are a moderate meteor shower with peak hourly rates at 10 to 15 meteors per hour.  This rate is of course from a dark location meaning city observing will be minimal.  To observe the Orionids go outside after 10:00 p.m. and look for the constellation Orion low in the east.  As the night continues Orion will rise higher in the south offering a better chance at seeing meteors.  The Orionids are not the best meteor shower of the year but they are one of the most famous as they are caused by Comet Halley.  To learn more about this meteor shower and others visit http://amsmeteors.org/    

Messier Object of the Week

For the last few years 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.  So in 2015 we will change things a bit for this section and instead of highlighting one constellation for each month we will highlight one Messier object a week using the Astronomical League’s Binocular Messier program as our guide.  

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 2015 observing year is the Binocular Messier 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 observing program is an introduction to the Messier catalog.  The Messier catalog was created by French astronomy Charles Messier.  He was a comet hunter that would periodically find objects that could be confused for comets.  To help others avoid these objects when looking for comets he created a list that consists of objects that today we know are star clusters, nebula and galaxies.  The Messier catalog is a great introduction to deep sky observing for northern hemisphere observers and as such it will be our guide for each week of 2015.  Each week we will highlight a Messier object that is part of the Astronomical League’s binocular Messier program.  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 Messier object for the week of October 5 is the open star cluster Messier 52 (M52).  This open star cluster was one of the first Messier objects discovered by Charles Messier.  M52 is a group of nearly 200 stars that formed about 35 million years ago.  At a distance of roughly 5,000 light years M52 shines with an apparent magnitude of 7.2.  Its Trumpler classification is I, 2, r meaning it is a well detached cluster with a central concentration, it stars have a moderate range in magnitudes and it is a rich cluster with over 100 stars.  The Trumpler Classification system is a useful tool for describing a star cluster and also preparing you for what you should look for.  Follow the link below for a description of the Trumpler Classification system.

Trumpler Classification System      

Finding M52 is pretty simple as it is located right next to the prominent stars of the constellation Cassiopeia. To find Cassiopeia look northeast around 8:00 p.m. and you will find the bright W-shape of Cassiopeia.  Next identify the stars Alpha and Beta Cass.  These are the two bright stars on the western side of Cassiopeia.  Next using your binoculars scan from Alpha to Beta Cass and continue to the northwest another 6.5 degrees.  This is where you will find M52.  Through binoculars you will notice a fuzzy nebulous patch of light.  Use the map below to help find this week’s guide stars and Messier object M52.

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

The Messier object for the week of October 12 is the open star cluster Messier 29 (M29).  This little open cluster contains approximately 50 stars which lie at a distance of about 4,000 light years.  The stars in this cluster are around10 million years old and are part of the Cygnus OB1 association.  OB Stellar associations are groupings of 10 to a few hundred massive hot O and B class stars.  The stars in these associations tend to have the same or similar ages and are representative of periods of star formation.  Frequently these massive hot stars will excite the molecular clouds that are near them creating beautiful emission nebulae.  Great examples of these are the North American Nebula (NGC 7000), the Lagoon Nebula (M8) and the Great Orion Nebula (M42).  The Cygnus OB1 association which M29 is a part of contributes to the excitation of a large molecular complex called the Cygnus X region.  This is a bright radio source in Cygnus that has been found to be one of the largest star forming regions in the Milky Way.   

Observing M29 with binoculars will reveal a small fuzzy patch of light.  Small telescopes will reveal about 6 bright stars.  These are all blue supergiant stars that individually are around 160,000 times brighter than the Sun.  The six bright stars visible in a small telescope appear to be in the shape of a hyperboloid and are thus frequently called the Cooling Tower cluster.  

To find M29 first locate the constellation Cygnus as describe above.  Then find the bright star Gamma Cygni.  From here scan about 1.5 degrees to the southeast and you will find M29.  Again through binoculars it appears as a small fuzzy patch of light and through telescopes individual stars will be resolved.  Follow the links below for more information about M29 and those objects associated with it. 

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

http://messier.seds.org/m/m029.html

http://apod.nasa.gov/apod/ap120118.html 

The Messier object for the week of October 19 is the supernova remnant Messier 1 (M1) which is more famously known as the Crab Nebula.  M1 is an expanding cloud of gas shed off by a massive star that went supernova.  The earliest records of this supernova date back to July 4, 1054 C.E. when Chinese astronomers recorded a new star that was visible in the day time for about three weeks.  There is also a famous rock art site in the Chaco Canyon area that indicates that the cultures in the area witnessed and recorded the event as well.  

Supernovae like the one that created the Crab Nebula are explosions that resulted from a massive star collapsing at the end of its stellar life.  Supernovae are not common as most stars simply are not massive enough to reach this fate.  Most stars like the Sun will evolve into red giants and eventually will lose their outer layers spending the rest of their existence as a small white dwarf star.  This process is all related to nuclear fusion which is the process in which a star converts lighter elements into heavier ones.  Once nuclear fusion ceases a star’s core will collapse due to the inward pull of gravity.  This cycle may occur numerous times with each cycle producing heavier elements than the one before.  Nuclear fusion in the most massive stars can produce elements up to iron.  Stars that make it this far are destined for one final core collapse that can blast the star apart creating an expanding cloud of gas.  All elements heavier than hydrogen and helium were produced in the heart of a star through nuclear fusion.  Any elements heavier than iron form through a process called nuclear synthesis.  Elements such as gold, silver and platinum are only possible thanks to the extreme energy released during a supernova.  

The Crab Nebula is located about 6,300 light years from us in the constellation Taurus the Bull.  The violent stellar explosion that created this object was seen about 1,000 years ago but really it occurred about 7,000 years ago.  Events like this are not common and it is estimated that they occur every 50 - 100 years however it has been over 300 years since we have seen one in the Milky Way Galaxy.  The star that exploded creating the Crab Nebula continued to collapse forming what is called a neutron star.  This small ultra-dense core of the star spins rapidly at about 30 times a second.  Neutron stars that spin like this are called pulsars because they have a beacon like pulse of radiation.  

M1 will be one of the most challenging objects we will include in the night sky update.  It will be a target that many of us will likely have to travel to darker skies to see but it is doable in binoculars.  Visually it will not be the most striking object as it appears as a small and faint nebulous patch of light.  The appeal to this type of object is in its details.  Learning about the fine details of an object is part of the interest in looking for very dim fuzzy patches of light.  M1 will be easy to locate but it will be hard to see.  To locate M1 you will first have to find the constellation Taurus the Bull.  This is easily accomplished by locating Orion the Hunter and then following his belt stars to the west and you will find a V-shape of stars.  This V-shape is a beautiful open star cluster called the Hyades which represents the nose of Taurus.  By following a line through the southern side of the Hyades you will find a bright star called Zeta Tauri.  About 1.5 degrees to the north of this star is where you will find M1.  I would recommend using a map or computer program that displays stars down to 8th magnitude.  Free planetarium software called Stellarium will allow you to do this.  Follow the links below for help in tracking down the Crab Nebula (M1).

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

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

http://www.stellarium.org/                            

Our next Star Party will be held on Friday, November 6, 2015, 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 around 8 p.m.  Regardless of the weather on November 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.  For more information about the St. Louis Astronomical Society visit their website at www.slasonline.org

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