This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Friday, November 25, 2022.
Information updated weekly or as needed.
Times given as local St. Louis time which is Central Standard Time (CST). 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 -6 hours when CST.
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 December 2, join us indoors in our planetarium theater for “The Sky Tonight”. Showtime is at 7 p.m.
*** There will not be a First Friday in January 2023. ***
Observing Highlight of the Week
Mars at opposition in 2018. Image credit: NASA, ESA, and STScI
With December knocking at the door, Mars will be our highlight for the new couple of weeks. Every 26 months, Earth catches up to Mars in our orbit and then passes it by. This behavior is observable in a few ways. Visual magnitude, changing apparent motion and details on the Martian surface are all the result of Earth catching up to Mars.
A long time ago humans learned planets were different from stars because they moved independently of the background sky. The name planet comes from the Greek term Astra Planeta or wandering star. As the planets appear to wander amongst the stars, it was found that they always stay in the same path that you find the Sun and Moon. This path is marked by the zodiac constellations representing the plane of the solar system.
Mars is currently exhibiting retrograde motion. Normally, Mars appears to shift in a west to east motion caused because planets orbit the Sun counterclockwise. As Earth catches up to Mars and passes it by, it appears to move backwards for several months. This backward apparent motion is called retrograde, and it is an illusion caused by seeing Mars from changing angles relative to the background stars. For those that do not have telescopes, this is something you can watch until January 12, 2023, when retrogression ends.
Another benefit of Earth getting closer to Mars is the planet will look larger. It should be stressed that to the unaided eye, Mars will always appear as a small dot in the sky. There is a hoax that surfaces around opposition years stating that Mars and the Moon will appear the same size but that is NOT correct. Mars will only appear larger when view through a telescope. In May this year, Mars exhibited an angular diameter of 6 arcseconds. On December 1, 2022, when Earth and Mars are at their closest for the next 26 months, Mars will appear 17.2 arcseconds in diameter. The variance is small, but it is enough that backyard telescopes will reveal surface features. Mars is the only planet we can see its surface with a backyard telescope.
Lastly, on December 7, 2022, Mars will reach opposition which is when Mars will appear near the anti-solar point in the sky. Another way to think of this is Mars will appear opposite the Sun. When this happens, Mars appears brighter due to the opposition effect. Shadows point away from the light source that cause them. On the Martian surface, mountains, cliffs, craters even dust grains cast shadows. When at opposition Earth is between Mars and the Sun, so the shadows cast by Martian surface point away from us. The net result is Mars looks brighter. This is the same reason why a full moon looks brighter.
The next couple of weeks, Mars will be a prime target to watch. Those with telescopes will be treated to surface views while naked eye observers can enjoy tracking the apparent motion of Mars. Next week we will continue with Mars as on December 7, 2022, Mars will disappear behind the Moon for about an hour, but more on that next week.
The Sun and Moon
The Moon as seen from the International Space Station, on July 31, 2011.
Credit: NASA
Sunrise is at 6:54 a.m. on Friday, November 25 and sunset is at 4:42 p.m. providing us with roughly 10 hours of daylight. Even after sunset, the light from the Sun will dimly illuminate our sky for roughly 1 hour and 30 minutes. This period is called twilight, which ends around 6:15 p.m. this week. For those with a sundial, local noon occurs around 11:47 a.m. this week.
| Day | Sunrise | Sunset |
|---|---|---|
| 2022-11-25 | 6:54 a.m. | 4:42 p.m. |
| 2022-11-26 | 6:55 a.m. | 4:41 p.m. |
| 2022-11-27 | 6:56 a.m. | 4:41 p.m. |
| 2022-11-28 | 6:57 a.m. | 4:41 p.m. |
| 2022-11-29 | 6:58 a.m. | 4:40 p.m. |
| 2022-11-30 | 6:59 a.m. | 4:40 p.m. |
| 2022-12-01 | 7:00 a.m. | 4:40 p.m. |
| 2022-12-02 | 7:01 a.m. | 4:40 p.m. |
| 2022-12-03 | 7:02 a.m. | 4:39 p.m. |
Moon
Moonrise for Friday, November 25 was at 9:03 a.m. and moonset occurred at 6:11 p.m. Friday, November 25, the Moon will exhibit a waxing crescent phase with 6% of the lunar disk illuminated. First quarter moon occurs on November 30, 2022, at 8:37 a.m.
International Space Station (ISS) Observing
Visible passes of ISS from St. Louis for the week of November 25 occur during evening hours. The best pass occurs on the evening of December 3. Use the table below for information about this and other visible passes this week.
Catch ISS from St. Louis starting Friday, November 25
| Date | Starts | Max. altitude | Ends | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Time | Alt. | Az. | Time | Alt. | Az. | Time | Alt. | Az. | ||
| 01 Dec | -1.2 | 18:39:18 | 10 | NNW | 18:39:55 | 14 | NNW | 18:39:55 | 14 | NNW |
| 02 Dec | -2.1 | 17:50:49 | 10 | NNW | 17:53:17 | 19 | NNE | 17:53:25 | 19 | NNE |
| 03 Dec | -2.1 | 18:38:13 | 10 | NW | 18:39:57 | 28 | NW | 18:39:57 | 28 | NW |
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 Visible Planets
Looking southeast at 7:00 p.m. on November 26, 2022. Credit: Stellarium, EG
Looking south at 2:00 a.m. on November 27, 2022. Credit: Stellarium, EG.
This week, three naked eye planets are visible. Mars rises in the early evening and is visible most of the night. Jupiter and Saturn rise before sunset and will be visible once it is dark.
Mars
Mars rises at 5:27 p.m. Start looking for the red planet around 6:30 p.m. as it clears trees and buildings. Mars is headed towards opposition later this year on December 7, 2022.
Jupiter
Now past opposition, Jupiter will be visible about 30 minutes after sunset. Jupiter reaches superior conjunction on April 11, 2023. As we progress towards this date, we will see Jupiter slowly wander towards the Sun.
Saturn
Now past opposition, Saturn rises before the Sun sets. You can find this giant world in the south about 45 minutes after sunset. Saturn is still a fine target though telescopes and will be a highlight of the evening sky for the rest of the year.
James S. McDonnell Planetarium
Night Sky Update: November 25 – December 3, 2022
