This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Saturday, October 28, 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. This all changes on November 5, 2023, when Daylight Saving Time ends. Once this occurs, we use Central Standard Time (CST), which is -6 hours from Universal Time.
Observing Highlight of the Week
Using the James Webb Space Telescope ‘s NIRCam instrument, scientists discovered a high speed jet stream in Jupiter’s atmosphere above its equator. Image credit: NASA, ESA, CSA, STScI, Ricardo Hueso (UPV), Imke de Pater (UC Berkeley), Thierry Fouchet (Observatory of Paris), Leigh Fletcher (University of Leicester), Michael H. Wong (UC Berkeley), Joseph DePasquale (STScI)
This week’s highlight is the planet Jupiter. If you have been outside a few hours after sunset recently, chances are you have noticed a bright star like object rising in the east. This is Jupiter. The giant planet has been rising earlier each week as it approaches opposition on November 2, 2023. Opposition is when superior planets are brightest, so if you have a telescope at home, now is the best time to observe Jupiter.
Opposition is the point in which an object appears opposite the Sun in the sky. This is only possible if an object is farther from the Sun than the observer. Planets that are farther from the Sun are called superior planets while those that are closer are called inferior. Inferior planets cannot appear at opposition.
The rate in which opposition occurs for each planet varies due to their distance from the Sun. For Mars it is about 26 months, Jupiter is about 13 months, Saturn is 378 days, Uranus is 369 days and Neptune is 367 days. This translates to most years Jupiter, Saturn, Uranus and Neptune reach opposition, while Mars does so every 2 years and 2 months.
Opposition is the ideal time to view these planets for a few reasons. Most notably, during opposition, an object appears brighter due to the opposition effect. When an object nears the anti-solar point in the sky, any shadows cast by surface or atmospheric features point away from the viewer. This results in more bright and less dark spaces causing the object to appear brighter. Additionally, when at opposition, an object will be near its closest approach to Earth for the current apparition. When we are closer to something, its angular size appears larger.
Jupiter reaches opposition on November 2, 2023. On this date, Jupiter will rise as the Sun sets, it reaches its highest altitude around midnight and sets around the time of sunrise. Jupiter is already near its peak brightness and will remain that way through the first week or two in December. On November 2, 2023, Jupiter is expected to appear as a -2.9-magnitude object with an angular diameter of 49.5 arcsec.
Those with telescopes have a few good opportunities to see the Great Red Spot (GRS) and a few shadow transits this week. On October 31, 2023, the GRS will transit the visible side of Jupiter from 11 pm to 2 am. The same thing occurs again on November 1 and 3 from 7 pm to 10pm and midnight to 4 am respectively. Also, on October 3, Jupiter’s moon Europa and its shadow will transit the visible side of Jupiter from roughly 8:19 pm to 10:30 pm. Finally, on October 4/5, Jupiter’s moon Io and its shadow will transit from 11 pm to 1 am followed by a GRS transit from 1 am to 5 am. Moderate sized telescopes are recommended for viewing these events.
The Sun and Moon
The Moon as seen from the International Space Station, on July 31, 2011.
Credit: NASA
Sun
Sunrise is at 7:23 a.m. on Saturday, October 28 and sunset is at 6:05 p.m. providing us with roughly 11 hours of daylight this week. 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 7:43 p.m. this week. For those with a sundial, local noon occurs around 12:44 p.m. this week.
Daylight Saving Time ends on November 5, 2023. Before going to bed on November 4, 2023, remember to set your clocks one hour back.
| Day | Sunrise | Sunset | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 28-Oct | 7:23 a.m. | 6:05 p.m. | ||||||||||
| 29-Oct | 7:24 a.m. | 6:04 p.m. | ||||||||||
| 30-Oct | 7:25 a.m. | 6:03 p.m. | ||||||||||
| 31-Oct | 7:26 a.m. | 6:02 p.m. | ||||||||||
| 1-Nov | 7:27 a.m. | 6:01 p.m. | ||||||||||
| 2-Nov | 7:28 a.m. | 6:00 p.m. | ||||||||||
| 3-Nov | 7:29 a.m. | 5:59 p.m. | ||||||||||
| 4-Nov | 7:30 a.m. | 5:57 p.m. | ||||||||||
| 5-Nov | 6:32 a.m. | 4:56 p.m. |
Moon
Moonrise for Saturday, October 28 was at 6:01 p.m. and moonset occurred at 8:19 a.m. on the following day. On Saturday, October 28, the Moon reached its full moon phase. By the end of the week the Moon will exhibit a waning crescent phase with roughly 46% disk illumination.
International Space Station (ISS) Observing
There are several visible passes of ISS from St. Louis for the week of October 28. They occur during morning hours. The table below lists the best of these passes that will be seen from St. Louis. If you do not live in the area, you can use https://heavens-above.com/ to set your viewing location and get times for where you are.
Catch ISS from St. Louis starting Saturday, October 28, 2023
| Date | Starts | Max. altitude | Ends | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Time | Alt. | Az. | Time | Alt. | Az. | Time | Alt. | Az. | ||
| 03 Nov | -2 | 6:27:07 | 11 | NNW | 6:29:52 | 27 | NNE | 6:32:47 | 10 | E |
| 05 Nov | -3.6 | 5:27:23 | 18 | NW | 5:29:43 | 68 | NE | 5:33:03 | 10 | ESE |
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 8:00 p.m. on October 29, 2023. Credit: Stellarium, EG
Looking southeast at 5:00 a.m. on October 30, 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 8:00 p.m. Venus will be easy to find in the east before sunrise.
Venus
Venus rises this week around 3:37 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 gibbous phase with roughly 54% disk illumination. Now that Venus is past dichotomy, it is beginning to head back towards the Sun from our perspective. As this continues, Venus’s disk illumination will increase as it heads towards superior conjunction on June 4, 2024.
Jupiter
Jupiter rises at 6:19 p.m. About one hour after Jupiter rises, it should be easy to spot for those with clear eastern horizons. Jupiter will rise about 30 minutes earlier each week. Jupiter reaches opposition 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. Saturn will set by 2:01 a.m.
James S. McDonnell Planetarium
Night Sky Update: October 28-November 5, 2023