This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Tuesday, August 9. 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 6:10 a.m. on Tuesday, August 9 and sunset is at 8:02 p.m. providing us with roughly 14 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 9:43 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 Tuesday, August 9 occurs at 12:40 p.m. and moonset will occur at 11:51 p.m. On Tuesday August 9 the Moon will be exhibiting a waxing crescent phase with 40% of the lunar disk illuminated. First quarter moon occurs on August 10 at 1:21 p.m.
International Space Station (ISS) Observing
Visible passes of ISS from St. Louis for the week of August 9 are during the evening hours. The best of these occur on the evenings of July 12, 14 and 15. Use the table below for more information regarding these passes and others occurring this week.
Catch ISS flying over St. Louis starting Tuesday, August 9.
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:
The Planets Visible Without a Telescope
Both Mercury and Venus are in the process of starting another evening apparition. Unfortunately this evening apparition of Mercury will not be very good as Mercury’s altitude 30 minutes after sunset will be under 10°. Mercury will reach maximum eastern elongation on August 16, 2016. Mercury sets by 9:03 p.m.
Venus is starting another evening apparition so be on the lookout for the brightest planet low in the west just after sunset. Any kind of tree cover or buildings to the west will obscure your view so make sure to get to a place with as clear of a western view as possible. Your best chance to see Venus right now will be to get to a high spot between 8:20 p.m. and scan the western horizon. This unfortunately will only be about 20 minutes after sunset so use caution and make absolute sure that the Sun has set as looking directly at the Sun can do irreversible eye damage. Viewing times will slowly get better as the week progresses. Venus will set by 8:51 p.m. During this long apparition Venus reaches maximum eastern elongation on January 12, 2017.
The Red planet is currently found in Scorpius rising before the Sun and can be easily seen by 8:30 p.m. in the southern sky. Mars sets by 12:26 a.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 at about 8:30 p.m. Jupiter sets at 9:34 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
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 1:12 a.m.
2016 Perseid Meteor Shower
The annual Perseid meteor shower is once again upon us peaking this week on August 12. This annual meteor shower is caused as Earth passes through debris left by Comet 109P/ Swift-Tuttle. As meteors from this comet enter our atmosphere they excite the gases around them creating a bright but brief streak of light.
The name of a meteor shower comes from where its radiant is located. The radiant of a meteor shower is the spot in the sky that all the meteors appear to come from. The Perseids have a radiant that moves through Perseus every August. Typically the Perseid meteor shower can produce 100 meteors per hour at its peak if viewed from a dark location. For city observers it will be closer to 10-15 per hour.
This year the Perseids are expected to have an outburst producing as many as 200 per hour at peak times. The outburst is expected because instead of grazing the debris field left by this comet we will be passing through a denser portion of it. This is caused by Jupiter’s gravitational influence affecting where the debris is. Sadly the peak this year occurs when it is daytime for us in St. Louis.
To view the Perseid meteor shower it is best to go outside between the hours of 1:00 a.m. and 4:00 a.m. on August 12. If it is cloudy at this time the Perseids remain active one to two days before and after its peak date. For more information follow the link below.
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
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.
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.