This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Saturday, January 27, 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
The red star seen in the middle of this image is the carbon star R Leporis. Image credit: Stephen Rahn.
The highlight for this week is the constellation Lepus the Hare. This small constellation is often overlooked due to its proximity to the larger and more famous constellation Orion. Lepus is worth some of your observation time as it offers a handful of targets that are within reach of modest binoculars.
The easiest way to find Lepus is to start at Orion. The best identifier for Orion are the three belt stars Alnitak, Alnilam and Mintaka. The two bright stars below these are Saiph and Rigel. Lepus is found south of these two stars. Covering an area of 290 square degrees of sky, Lepus is 51st in terms of size. Its brightest stars range from 3rd to 5th magnitudes so it will be dimmer than the more prominent constellations around it. Lepus’s two brightest stars are Arneb and Nihal. They are found about 8° and 12° south of Saiph respectively.
About 4° east of Nihal is the star, Gamma Leporis. Using binoculars, you will find that Gamma Leporis is a double star. The pair of stars is separated by 96 arcseconds which makes Gamma Leporis an easy split for binoculars. The primary component is an F-class hydrogen fusing dwarf star. The secondary star is a K-class dwarf star. Through binoculars, the primary will appear yellowish white, and the secondary will have a slight orange color.
Another good binocular target in Lepus is the globular star cluster M79. Globular star clusters are ancient groups of stars that contain tens of thousands of members. M79 Is roughly 41,000 light years from us and it contains roughly 150,000 stars. The age of the cluster is roughly 11.7 billion years. Current research suggests this globular cluster may have been stolen from a nearby dwarf galaxy called the Canis Major Dwarf Galaxy, however, this idea is still debated. M79 has an apparent magnitude of 8.56. Unfortunately, this means those of us in light polluted areas will need to use moderate to large binoculars to spot the cluster. Through binoculars, M79 will appear as a faint patch of light. Large backyard telescopes are needed to begin resolving stars in the cluster. The easiest way to find M79 is to follow a path that runs from the star Arneb through the star Nihal. M79 is found roughly 4° south of this pair of stars.
Another star worth noting is the variable star R Leporis. It brightness fluctuates from 5.5 to 11.7 magnitude over a period of 432 days. R Leporis is a Mira type variable which are highly evolved red giant stars on the ASG branch of the Herztsprung-Russell diagram. They have undergone helium fusion in their core and are nearing the end of their time in space. Mira stars fluctuate in temperature and size which is the cause of their large variance in luminosity. If you would like to learn the finer details about Mira class variables, I recommend starting with an AAVSO article you can find here. Current observations for R Leporis put it at roughly 8.5 magnitude.
To help you find the targets listed above, I recommend using a sky atlas with stars down to magnitude 7.5 or dimmer. Another option is to use any of the planetarium software that is available these days. The software I frequently use is called Stellarium. It is free and available for all platforms.
The Sun and Moon
The Moon as seen from the International Space Station, on July 31, 2011.
Credit: NASA
Sun
Sunrise is at 7:11 a.m. on Saturday, January 27 and sunset is at 5:16 p.m. providing us with a little over 10 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 6:49 p.m. this week. For those with a sundial, local noon occurs around 12:13 p.m. this week.
| Day | Sunrise | Sunset | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 27-Jan | 7:11 a.m. | 5:16 p.m. | ||||||||||
| 28-Jan | 7:10 a.m. | 5:18 p.m. | ||||||||||
| 29-Jan | 7:09 a.m. | 5:19 p.m. | ||||||||||
| 30-Jan | 7:08 a.m. | 5:20 p.m. | ||||||||||
| 31-Jan | 7:08 a.m. | 5:21 p.m. | ||||||||||
| 1-Feb | 7:07 a.m. | 5:22 p.m. | ||||||||||
| 2-Feb | 7:06 a.m. | 5:23 p.m. | ||||||||||
| 3-Feb | 7:05 a.m. | 5:25 p.m. | ||||||||||
| 4-Feb | 7:04 a.m. | 5:26 p.m. |
Moon
Moonrise for Saturday, January 27 is at 7:14 p.m. and moonset occurs at 8:56 a.m. the following day. On Saturday, January 27, the Moon will exhibit a waning gibbous phase with roughly 96% disk illumination. By the end of the week the Moon will exhibit a waning crescent phase with 31% disk illumination. Last quarter moon occurs on February 2, 2024, at 5:18 p.m.
International Space Station (ISS) Observing
There are several visible passes of ISS from St. Louis for the week of January 27. 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 27, 2024
| Date | Starts | Max. altitude | Ends | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Time | Alt. | Az. | Time | Alt. | Az. | Time | Alt. | Az. | ||
| 31 Jan | -3.9 | 18:54:47 | 10 | NW | 18:58:09 | 83 | NE | 18:58:24 | 74 | ESE |
| 01 Jan | -3.4 | 18:06:54 | 10 | NW | 18:10:10 | 47 | NE | 18:13:15 | 11 | ESE |
| 03 Jan | -3 | 18:07:33 | 10 | WNW | 18:10:51 | 56 | SW | 18:14:08 | 10 | SE |
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 28, 2024. Credit: Stellarium, EG
Looking southeast at 6:15a.m. on January 29, 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 5:15 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 high in the south once it is dark outside. Jupiter will set around 12:33 a.m.
Saturn
Start looking for Saturn in the southwest about 30 minutes after sunset. Saturn will set around 7:31 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 27-February 4, 2024
