This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Saturday, January 25, 2025.
Information updated weekly or as needed.
Times given as local St. Louis time this week will be in 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.
Join us for our next star party, Friday, February 7, 2025, held in association with the St. Louis Astronomical Society.
For details, see the information at the bottom of this page or visit: https://www.slsc.org/explore/mcdonnell-planetarium/public-telescope-viewings
Observing Highlight of the Week
The constellation Leo is one of the 13 constellations the Moon passes through. The next time you will find the Moon in Leo is February 11, 2025. Image created using Stellarium.
For those tired of the arctic blast there is good news on the horizon. If you look east around 9 pm, you will find a bright sickle shaped group of stars. This group of stars is the head of the constellation Leo. When you can see Leo rising in evening hours, you know spring is just around the corner.
Ancient people tracked the apparent motions of the sky, making note of what was visible and when. Eventually the familiar patterns of stars they looked for became a kind of calendar that marked key points in a year. When and where something was rising informed many of our ancestors sacred and secular activities. One of the most significant of these was our shift into agrarian lifestyles.
As we became farmers, knowledge of the seasons was paramount to our success. Farmers today no longer look to the stars to determine when we should plant and harvest crops, but our success as agrarian societies is still rooted in these ancient lessons.
While you wait for winter to end, you can follow in your ancestors’ footsteps knowing spring will soon be upon us. Start thinking about those gardens you want to plant this year. When to start these activities can be a bit confusing to anyone new to gardening so look for those local resources that might be available through libraries, nature centers or other such locations. Here at the Saint Louis Science Center, you can visit our GROW exhibit and talk with our educators about plants or other agriculture topics. We also have a weather station at the planetarium that has soil probes that measure soil temperatures.
T CrB Nova Update 1/26/2025
If you are still interested in seeing the recurrent nova T Coronae Borealis, there is still hope. The nova has not yet occurred meaning we are in a waiting game. It could happen this year or it could happen next year. We will have to wait and see. If you are still interested in this event, the part of the sky the nova will appear in is rising earlier each night. By 1:30 am, the constellation Corona Borealis will be over 10° above the eastern horizon. This should make it visible for most if you have a decent view of the east. Spaceweather.com is still posting magnitude estimates from the AAVSO. This is the resource I recommend following to keep up with any changes in the star’s brightness.
The Sun and Moon
The Moon as seen from the International Space Station, on July 31, 2011.
Credit: NASA
Sun
Sunrise is at 7:12 am on Saturday, January 25 and sunset is at 5:15 pm providing around 10 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 6:47 pm this week. For those with a sundial, local noon occurs around 12:14 pm on January 19, 2025.
Moon
Moonrise for Saturday, January 25, was at 4:14 am and moonset occurs at 1:13 pm. The Moon starts the week off with a waning crescent phase exhibiting 14% disk illumination. By the end of the week the Moon will exhibit a waxing crescent phase with 15% disk illumination. New moon occurs on January 29, 2025, at 6:36 am.
International Space Station (ISS) Observing
There are several visible passes of ISS from St. Louis for the week of January 25. 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.
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 6:00 pm on January 25, 2025. Credit: Stellarium, EG
Looking west at 1:00 am on January 26, 2025. Credit: Stellarium, EG
This week, four naked eye planets are visible. All four are visible in the evening sky with Venus, Jupiter and Saturn visible not long after sunset. Mars rises a little later, becoming visible in evening hours.
Venus
Venus will be visible in the southwest after sunset. You can start looking for Venus about 15 minutes after the Sun sets. Venus will set by 9:01 pm. Venus is now headed towards inferior conjunction which occurs on March 22, 2025. Over the next couple of months, Venus will continue to appear closer to the Sun until we lose Venus to the Sun’s glare.
Mars
Mars is now past opposition. Look for it rising in the east about 40 minutes after sunset. The current apparition of Mars will continue throughout the rest of 2025. Watch for the Red Planet as it shifts westward through the year.
Jupiter
Now past opposition, Jupiter rises before the Sun sets. Look for Jupiter high in the east as the sky begins to darken. Jupiter sets around 3:30 am.
Saturn
Saturn will be visible in the southwest shortly after sunset. Saturn now sets around 8:29 pm. Each week Saturn will set about 25 minutes earlier than it did the week before.
Our next Star Party will be held on Friday, February 7, 2024, from 5:30 pm until 8:30 pm
On the first Friday of each month, the St. Louis Astronomical Society and the Saint Louis 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 February 7, join us indoors in our planetarium theater for our “Monthly Sky Lecture.” Showtime is at 7 pm
This free, indoor star program will introduce you to the current night sky. Doors open 15 minutes before show time. Shows begins at 7 p.m. Sorry, no late admissions due to safety issues in the darkened theater.
The St. Louis Astronomical Society helps host the monthly Star Parties at the Saint Louis Science Center. In addition to our nighttime viewings, they also help facilitate our daytime event called Solar Sundays. These daytime viewing sessions occur on the 3rd Sunday of each month. Visit SLAS’s website linked above to learn about other telescope events SLAS hosts around the St. Louis area.
James S. McDonnell Planetarium
Night Sky Update: January 25-February 1, 2025
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