This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Saturday, October 7, 2023.
Information updated weekly or as needed.
Times given as local St. Louis time which is Central Daylight Time (CDT). For definitions of terminology used in the night sky update, click the highlighted text. If relying on times posted in Universal Time (UT), St. louis is -5 hours when CDT.
Public Telescope Viewings
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 November 3 , join us indoors in our planetarium theater for “The Sky Tonight”. Showtime is at 7 p.m. There is no First Friday event in July.
Observing Highlight of the Week
Annular eclipse seen from Hsinchu City, Taiwan on May 21, 2012. Image credit: Teddy 190902.
With the October 14, 2023, annular eclipse one week away, it is a good time to review how to safely view a solar eclipse. Looking directly at the Sun can cause permanent loss of vision so it is extremely important to know how to safely view the Sun. As I am not a medical professional, I do not want to speak with any authority on eye health, but if you are curious about how the Sun damages your eye, look up the disease solar retinopathy. The American Academy of Ophthalmology defines solar retinopathy as “a photochemical toxicity and resultant injury to retinal tissues, usually occurring at the fovea”. Further reading on this subject is advised as it is important to understand this topic. The American Academy of Ophthalmology has an excellent synopsis of the disease and its cause. You can find that article at https://eyewiki.aao.org/Solar_Retinopathy
There are several myths about viewing eclipses that often convince people to avoid viewing an eclipse at all. If someone just doesn’t feel safe viewing the event, I would never try to coerce them, but with an understanding of the equipment necessary for safe solar viewing, the Sun can be one of the most interesting objects to observe.
To safely observe an eclipse, you should either use a projection method, or use a proper solar filter. Projection methods vary, but they all involve an object that has a small hole. Pinhole projectors you may remember making in school are a great way to view an eclipse. Taking an index card and cutting a small hole in it will allow light to project through the hole onto a screen in front of you. This will create a decent image of the eclipse as it occurs. Pasta spoons, colanders, leaves on a tree or anything else with a small hole can do this. Keep in mind though you never look through the hole, you just let sunlight stream through it.
The other safe method for viewing an eclipse involves proper safe solar filters of which there are several types. The most common and least expensive are called continuum filters. These allow a tiny portion of the visible light spectrum through to your eye. These filters are what are used in eclipse glasses but can also be made as full aperture filters for telescopes, binoculars and cameras. These will be the most accessible filters and are what most recommend for eclipse viewing. Unfortunately, there are people selling fake filters, so it is imperative that if you buy them make sure the filters are manufactured according to the ISO standards. The American Astronomical Society has an excellent article on how to check if your filters are safe. You can find that at eclipse.aas.org.
Other safe solar filters on the market are h-alpha and calcium K-line filters. These are specialized narrow-band filters that allow you to view the Sun in a target frequency of light. The best of these for visual observations is h-alpha. Viewing the Sun in this kind of light allows you to see the inner atmosphere of the Sun called the chromosphere. Here you can see features such as sunspots, filaments and prominence on any clear day. As these telescopes tend to be only good for looking at the Sun, they are not the best choice if you are just looking for something to view the eclipse. While the view they provide will be excellent, these telescopes come with a high cost. Entry level h-alpha telescopes start around $800 for just the OTA. If it is your first telescope, you are better off using a normal telescope with a full aperture continuum filter.
A third option for viewing the eclipse on October 14, 2023, is to find a live feed from someone streaming it as it occurs. This is a great option if the weather at your viewing site is not good. I imagine there will be several live feeds you can tune in to, but I would recommend NASA’s feed they plan to facilitate. They usually will have several feeds of the eclipse from different locations to accommodate any weather issues. You can watch NASA’s feed on October 14, 2023, starting at 10:30 a.m. at https://science.nasa.gov/eclipses/future-eclipses/eclipse-2023/2023-annular-eclipse-broadcast/
If done safely, the Sun is a rewarding and dynamic object to observe. We can use October 14, 2023, as a practice run for the next solar eclipse visible in North America. Next year on April 8, 2024, a total solar eclipse will be visible from Texas up to Maine. This will be the last total solar eclipse easily seen in North America until August 12, 2045. There are two other total solar eclipses visible from North America in 2033 and 2044, but they will be mostly seen from remote locations.
If you would like to learn more about eclipses, you will find several links below.
https://www.slsc.org/eclipses-2023-2024/
The Sun and Moon
The Moon as seen from the International Space Station, on July 31, 2011.
Credit: NASA
Sun
Sunrise is at 7:02 a.m. on Saturday, October 7 and sunset is at 6:34 p.m. providing us with roughly 11.5 hours of daylight. Even after sunset, light from the Sun will dimly illuminate our sky for about 1 hour and 30 minutes. This period is called twilight, which ends around 8:03 p.m. this week. For those with a sundial, local noon occurs around 12:48 p.m. this week.
| Day | Sunrise | Sunset | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 7-Oct | 7:02 a.m. | 6:34 p.m. | ||||||||||
| 8-Oct | 7:03 a.m. | 6:33 p.m. | ||||||||||
| 9-Oct | 7:04 a.m. | 6:31 p.m. | ||||||||||
| 10-Oct | 7:05 a.m. | 6:30 p.m. | ||||||||||
| 11-Oct | 7:06 a.m. | 6:28 p.m. | ||||||||||
| 12-Oct | 7:07 a.m. | 6:27 p.m. | ||||||||||
| 13-Oct | 7:08 a.m. | 6:26 p.m. | ||||||||||
| 14-Oct | 7:09 a.m. | 6:24 p.m. | ||||||||||
| 15-Oct | 7:10 a.m. | 6:23 p.m. |
Moon
Moonrise for Saturday, October 8 was at 12:57 a.m. and moonset occurred at 4:08 p.m. On Saturday, October 8, the Moon will exhibit a waning crescent phase with 28% disk illumination. New moon occurs on October 14, 2023, at 12:55 p.m.
An annular solar eclipse will occur on October 14, 2023. St. Louis will not see annularity, but we will experience a partial eclipse. You can learn more about this eclipse at https://www.slsc.org/eclipses-2023-2024/
International Space Station (ISS) Observing
There are no visible passes of ISS from St. Louis this week. This is a good time to learn more about other satellites that are visible. Others to try looking for are Tiangong and the Hubble Space Telescope. Both of these have several visible passes this week from St. Louis. Learn more about these at https://heavens-above.com/?lat=38.6312&lng=-90.2709&loc=Unnamed&alt=0&tz=CST
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°.
Detailed information regarding all unmanned exploration of our universe, missions past, present, and planned, can be found at Jet Propulsion Laboratories:
The Visible Planets
Looking southeast at 10:00 p.m. on October 8, 2023. Credit: Stellarium, EG
Looking southeast at 5:00 a.m. on October 9, 2023. Credit: Stellarium, EG
This week, three naked eye planets will be visible. Saturn will be found in the southeast once it is dark. Jupiter is easy to find in the east by 11:00 p.m. Venus will be easy to find in the east before sunrise.
Venus
Venus rises this week around 3:24 a.m. It will be easy to spot for most by 5:00 a.m. If you have a clear view of the planet, telescopes will reveal a crescent phase with roughly 42.1% disk illumination. Venus will reach maximum western elongation on October 23, 2023. You can count on seeing Venus in the east before sunrise for several months.
Jupiter
Jupiter rises at 7:49 p.m. About one hour after Jupiter rises, it should be easy to spot. Jupiter will rise about 30 minutes earlier each week. The ideal time to start looking for Jupiter will be after 10:00 p.m. Jupiter will reach opposition later this year on November 2, 2023.
Saturn
Start looking for Saturn in the southeast about 30 minutes after sunset. If you have lots of trees or buildings, you may have to wait an hour or so after it rises before it will be visible.
James S. McDonnell Planetarium
Night Sky Update: October 7-15, 2023