This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Saturday, January 13, 2024.
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.
Observing Highlight of the Week
South pole of asteroid 4 Vesta imaged by the Dawn spacecraft. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
The highlight for this week is the asteroid 4 Vesta. This week the asteroid will be moving through a favorable part of the sky making it easy to track down. 4 Vesta was discovered in 1807 by astronomer Heinrich-Wilhelm Olbers. It is named after the Roman goddess of the hearth and household by mathematician Carl Friedrich Gauss.
4 Vesta is the second most massive body in the main asteroid belt containing roughly 9% of the total mass of the belt. Vesta has an average diameter of 525.4 km. By comparison the Moon’s average diameter is 1730 km making it roughly 3.26 times larger than Vesta. Vesta appears to have formed about 1 to 2 million years after the birth of the solar system. 4 Vesta orbits the Sun every 3.63 years. It last reached opposition on December 21, 2023.
4 Vesta was one of the objects studied by NASA’s Dawn spacecraft. The Dawn mission’s primary objective was to advance the understanding of the origin and evolution of our solar system. This was primarily done by studying the two largest objects in the main belt: Ceres and Vesta. These two bodies are seen as proto planets that formed early after the Sun formed which meant they had access to higher amounts of short-lived radioactive materials. The radiation released as these materials decayed melted the interiors of Ceres and Vesta like other large bodies of the early solar system. This allowed denser material to sink down to the core while less dense material would rise becoming the mantle and crust. Like other planetary bodies, Vesta and Ceres are differentiated making them ideal targets to learn about the solar system formed. You can learn more about the Dawn mission at https://science.nasa.gov/mission/dawn/
To find 4 Vesta this week, you need to look for the constellation Taurus which is overhead by 10:00 p.m. With an apparent magnitude of 7.1, 4 Vesta should be easy to spot with moderate binoculars. From January 13 to January 23, the asteroid shifts between the stars Zeta and o Tauri. Each day, Vesta will shift about 20.88 arcmin towards the star o Tauri. To find these two stars first look for a bright V-shape of stars that represents the nose of the bull. If you follow the direction the bottom leg of the V-shape pointst, you will find the star Zeta Tauri.
When viewing the asteroid, it will always appear as a bright point of light. Backyard instruments will not reveal any details or shape of the asteroid. If you would like to see images of Vesta from the Dawn mission, visit https://science.nasa.gov/mission/dawn/multimedia/images/?pageno=2
Map showing the position of asteroid 4 Vesta on January 13, 2023 and the location of the stars Zeta and o Tauri. Map created using Stellarium.
The Sun and Moon
The Moon as seen from the International Space Station, on July 31, 2011.
Credit: NASA
Sun
Sunrise is at 7:18 a.m. on Saturday, January 13 and sunset is at 5:01 p.m. providing us with a bit over 9 hours and 30 minutes 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 6:35 p.m. this week. For those with a sundial, local noon occurs around 12:10 p.m. this week.
| Day | Sunrise | Sunset | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 13-Jan | 7:18 a.m. | 5:01 p.m. | ||||||||||
| 14-Jan | 7:18 a.m. | 5:02 p.m. | ||||||||||
| 15-Jan | 7:17 a.m. | 5:03 p.m. | ||||||||||
| 16-Jan | 7:17 a.m. | 5:04 p.m. | ||||||||||
| 17-Jan | 7:16 a.m. | 5:05 p.m. | ||||||||||
| 18-Jan | 7:16 a.m. | 5:06 p.m. | ||||||||||
| 19-Jan | 7:16 a.m. | 5:07 p.m. | ||||||||||
| 20-Jan | 7:15 a.m. | 5:09 p.m. | ||||||||||
| 21-Jan | 7:15 a.m. | 5:10 p.m. |
Moon
Moonrise for Saturday, January 13 was at 9:17 a.m. and moonset occurs at 7:47 p.m. On Saturday, January 13, the Moon will exhibit a waning crescent phase with roughly 9% disk illumination. By the end of the week the Moon will exhibit a waxing gibbous phase with 66% disk illumination. First quarter moon occurs on January 17, 2024, at 9:53 p.m.
International Space Station (ISS) Observing
There are several visible passes of ISS from St. Louis for the week of January 13. They occur during evening 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, January 13, 2024
| Date | Starts | Max. altitude | Ends | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Time | Alt. | Az. | Time | Alt. | Az. | Time | Alt. | Az. | ||
| 15 Jan | -3.6 | 18:45:55 | 10 | WSW | 18:49:14 | 63 | NW | 18:49:23 | 62 | NNW |
| 16 Jan | -3.8 | 17:58:02 | 10 | SW | 18:01:22 | 72 | SE | 18:03:44 | 18 | ENE |
| 18 Jan | -2.7 | 17:59:11 | 10 | WSW | 18:02:20 | 38 | NNW | 18:05:05 | 13 | NE |
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 southwest at 6:00 p.m. on January 13, 2024. Credit: Stellarium, EG
Looking southeast at 6:00 a.m. on January 14, 2024. Credit: Stellarium, EG
This week, three naked eye planets will be visible. Saturn and Jupiter are visible in the south once it is dark. Venus will be easy to find in the southeast before sunrise.
Venus
Venus rises this week around 4:52 a.m. It will be easy to spot for most by 6:00 a.m. Now that Venus is past dichotomy, it is headed 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 has passed opposition and as such it will rise before the Sun sets. Jupiter will be easy to spot in the south once it is dark outside. Jupiter will set around 1:23 a.m.
Saturn
Start looking for Saturn in the south about 30 minutes after sunset. Saturn will set around 8:18 p.m. Our window to see Saturn is starting to close as the planet approaches solar conjunction on February 28, 2024. As we approach this date Saturn will be found lower to the horizon each day eventually being lost to the Sun’s glare near the end of February.
James S. McDonnell Planetarium
Night Sky Update: January 13-21, 2024
