This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Tuesday, August 23.  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 2, 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 6:23 a.m. on Tuesday, August 23 and sunset is at 7:44 p.m. providing us with about 13.5 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 9:19 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 1:03 p.m. this week




 23 Aug

6:23 a.m.

7:44 p.m.

 24 Aug

6:24 a.m.

7:42 p.m.

 25 Aug

6:24 a.m.

7:41 p.m.

 26 Aug

6:25 a.m.

7:39 p.m.

 27 Aug

6:26 a.m.

7:38 p.m.

 28 Aug

6:27 a.m.

7:36 p.m.

 29 Aug

6:28 a.m.

7:35 p.m.

 30 Aug

6:29 a.m.

7:33 p.m.

 31 Aug

6:30 a.m.

7:32 p.m.


Moonrise for Tuesday, August 23 occurs at 11:18 p.m. and moonset will occur at 1:17 p.m. on the following day.  On Tuesday August 16 the Moon will be exhibiting a waning gibbous phase with 66% of the lunar disk illuminated.  Last quarter moon occurs on August 24 at 10:41 p.m.

International Space Station (ISS) Observing

There are no visible passes of ISS from St. Louis for the week of August 23.  So this week we will try observing the Hubble Space Telescope (HST).  There are a few passes this week however HST is normally low to the southern horizon.  Because of this we picked the two best this week and put them in the table below.

Catch HST flying over St. Louis starting Tuesday, August 23.

Date Mag


Max. altitude


Time Alt. Az. Time Alt. Az. Time Alt. Az.
23 Aug  2.5 20:15:11 10 SW 20:18:15 20 S 20:21:19 10 SE
24 Aug  2.6 20:05:22 10 SW 20:08:24 20 S 20:11:25 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

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

The Planets Visible Without a Telescope


Mercury has reach maximum eastern elongation.  This unfortunately means it will be increasingly difficult to see the elusive planet.  Mercury sets by 8:32 p.m.


Venus can be seen low in the west about 30 minutes after sunset in the western sky.  Venus sets by 8:38 p.m.  On Saturday, August 27 Venus and Jupiter will be in close conjunction.  The two planets less than ½° apart.  To learn more visit


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 11:55 p.m.


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 8:49 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


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 12:21 a.m.

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

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 August 2 is the sparse open star cluster NGC 7063.  Only having 12 known members this young group of stars will be difficult to pull out of the surrounding star field if you are observing from a light polluted location.  The stars are estimated to be only 140 million years old.  At a distance of 2,000 light years NGC 7063 shines with an apparent magnitude of 7.0.  It has a Trumpler classification of III, 2, p meaning it is detached from background stars but does not have a central concentration, it has a moderate range of stellar magnitudes and it has a poor stellar population with less than 50 members.

NGC 7063 is located in the constellation Cygnus the Swan.  As we have done for the last few weeks start by locating the Summer Triangle. To do this locate the three triangle stars Deneb, Vega and Altair.  These stars are members of the constellations Cygnus, Lyra and Aquila respectively which can be seen rising in the east by 10:00 p.m.  Once you can identify Cygnus grab your binoculars and scan about 11° east of the star Deneb and you will be in the vicinity of NGC 7063.  Once in this area try to identify the stars Tau and Sigma Cygnii.  If you can find these just look another 2° east and you will find NGC 7063.  Use the links below for help in finding this week’s target.

The deep sky object for the week of August 9 is the open start cluster NGC 7160.  Located in the constellation Cepheus, NGC 7160 is a sparse little star cluster that formed about 10 million years ago.  At a distance of 2,900 light years NGC 7160 shines with an apparent magnitude of 6.1.  It will be an easy target in binoculars however there are only 12 stars that will be seen so it will be easy to miss.  It has a Trumpler classification of II, 3, p meaning it is well detached from background star with a little central concentration, it has a large variance of stellar magnitudes and it is a star cluster with a poor population having under 50 members.

To find NGC 7160 you will have to find the constellation Cepheus.  The best way to do this is to first locate the Summer Triangle.  To do this locate the three triangle stars Deneb, Vega and Altair.  These stars are members of the constellations Cygnus, Lyra and Aquila respectively which can be seen rising in the east by 10:00 p.m.  Once you have identified the star Deneb in Cygnus look to the north for a house shape of stars which is Cepheus.  At the base of this house shape are two stars called Alpha and Delta Cephei.  NGC 7160 is located about halfway between these stars and about 4° north.  Use the maps below for help in finding this week’s target.

The deep sky object for the week of August 16 is the open star cluster NGC 7209.  Located in the minor constellation Lacerta the Lizard our target this week can be found just east of Cygnus the Swan.  At a distance of 2,900 light years NGC 7209 shines with an apparent magnitude of 6.7.  NGC 7209 contains about 25 stars that are estimated to be about 300 million years old.  These stars started to shine around the time the supercontinent Pangea was forming.  The Trumpler classification for NGC 7209 is III, 1, p meaning it is well detached from background stars with no central concentration, it has little variance in stellar magnitudes and it has a poor population of stars having less than 50 members.

In binoculars NGC 7209 will appear as a dim scattering of stars that covers an area of roughly 25 arc minutes.  As a comparison the Full Moon covers an area of 31 arc minutes.  Because this star cluster covers such a large part of the sky it will be easy to miss but if you take your time and use the references below it should be doable in most light polluted areas.

To find NGC 7209 you will need to find the constellations Cassiopeia and Cygnus.  Using the Summer Triangle identify the star Deneb in the Constellation Cygnus and the star Vega in Lyra the Harp.  Once you can do this this follow a path from Vega through Deneb until you see a bright W-shape of stars in the Northeast after 10:00 p.m.  This is the Constellation Cassiopeia.  Next grab your binoculars and slowly scan back and forth from Cygnus to Cassiopeia and you will find a diamond shape of stars connected to a small rectangle shape of stars.  This is the constellation Lacerta.  Look about 1.5° west of the small diamond shape that contains the stars Alpha and Beta Lacertae and you will find the open star cluster NGC 7243.  From here you will want to scan about 4° to the south and a little west to find our target NGC 7209.  Unfortunately I was unable to find a map that shows the star cluster’s location.  So your best bet will be to use the free planetarium software Stellarium to find the location or you can use the IAU constellation map below which does have the referenced guide stars Alpha and Beta Lacertae and the star cluster NGC 7243.

The deep sky object for the week of August 23 is the open star cluster NGC 7235 in the constellation Cepheus.  This two million year old star cluster contains roughly 30 stars.  With a distance of 12,400 light years NGC 7235 shines with an apparent magnitude of 7.7.  Like the last few star clusters covered this month it is well detached from background stars however it will be easy to miss as it has not central concentration.  Its Trumpler classification is III, 2, p which means it is well detached with no central classification, it has a moderate range of stellar magnitudes and it is a poor cluster with less than 50 members.

To find NGC 7235 you will need to locate the constellation Cepheus.  This can be easily done if you first locate the constellation Cassiopeia.  The W-shape of Cassiopeia can easily be identified by looking to the northeast around 10:00 p.m.  Once you can do this locate the stars Alpha and Beta Cassiopeiae and follow a path drawn between them to the north.  As you do this you will come across a house shape of stars which is the constellation Cepheus.  With Cepheus identified locate the star Epsilon Cephei in the southeast corner of Cepheus.  From this star NGC 7235 can be found about 1° to the northeast.  Use the maps below and the free planetarium software Stellarium for help in locating this week’s target.

Our next Star Party will be held on Friday, September 2, 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 September 2, join us indoors in our planetarium theater for “The Sky Tonight”.  Showtime is at 7 p.m.

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

The St. Louis Astronomical Society 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.