This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Friday, March 3, 2023.
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. Day Light Saving time starts on March 12, 2023, and run through November 5, 2023. Once in DST, St. Louis will be five hours behind UT.
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 April 7, join us indoors in our planetarium theater for “The Sky Tonight”. Showtime is at 7 p.m.
Observing Highlight of the Week
The constellation Leo is one of the famous zodiac constellations. Each month, the Moon will pass through Leo and the other zodiacal constellations as it progresses through its synodic cycle. Image created using Stellarium.
Looking east around 8:00 p.m. this week, you will find a backwards question mark shape of stars. This asterism is often called the Sickle of Leo as it represents the mane and head of the constellation Leo. Once Leo is visible in the early evening, it is an indicator that spring is right around the corner.
Astronomical spring officially begins at 4:24 p.m. on March 20, 2023 as the Sun heads north of Earth’s celestial equator. This day is called the vernal equinox. Since the start of winter, the Sun’s maximum altitude has increased each day and will continue to do so until June 21, 2023, when the Sun reaches one of its standstill points. These represent the Sun’s maximum and minimum altitudes each year. Solar standstills are the days called solstice which currently happen in June and December.
This behavior of the Sun has been known since ancient times as it was how we tracked the seasons. Ancient sites such as Stonehenge, Woodhenge and the Oyu Stones are examples around the world where ancient cultures were tracking the Sun’s behavior.
The night sky can also be used to track the changing seasons. The simplest way to do this is to watch the constellations as they change throughout the year. The current seasonal sky is typically what is visible in the east after sunset. This changes as we near the end of a season, when the current season will be seen overhead and south after sunset. Tonight what is in the south is the winter sky and replacing it in the east is spring. Leo is the first spring constellation to rise making it the herald of the season.
If you are having trouble finding the backwards question mark shape of Leo’s head, you can use the Big Dipper to guide you there. Using the back two stars in the bowl of the Big Dipper, following a southern path from them will take you to Leo’s head. The bright star at the bottom of the Sickle of Leo is called Regulus which is 21st brightest star seen at night.
As the hours pass, you will see Leo pass overhead by midnight and set by 5:30 a.m. The best time to see Leo and other objects in the constellation will be around midnight. This week the Moon will complicate finding deep sky targets but once it is darker latter in the month Leo is host to several galaxies that are fine targets for some backyard telescopes.
The Sun and Moon
The Moon as seen from the International Space Station, on July 31, 2011.
Credit: NASA
Sunrise is at 6:30 a.m. on Friday, March 3 and sunset is at 5:56 p.m. providing us with roughly 11.5 hours of daylight. Even after sunset, light from the Sun will dimly illuminate our sky for roughly 1 hour and 30 minutes. This period is called twilight, which ends around 7:24 p.m. this week. For those with a sundial, local noon occurs around 12:12 p.m. this week.
| Day | Sunrise | Sunset | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 3-Mar | 6:30 a.m. | 5:56 p.m. | ||||||||||
| 4-Mar | 6:29 a.m. | 5:57 p.m. | ||||||||||
| 5-Mar | 6:27 a.m. | 5:58 p.m. | ||||||||||
| 6-Mar | 6:26 a.m. | 5:59 p.m. | ||||||||||
| 7-Mar | 6:24 a.m. | 6:00 p.m. | ||||||||||
| 8-Mar | 6:23 a.m. | 6:01 p.m. | ||||||||||
| 9-Mar | 6:21 a.m. | 6:02 p.m. | ||||||||||
| 10-Mar | 6:20 a.m. | 6:03 p.m. | ||||||||||
| 11-Mar | 6:18 a.m. | 6:04 p.m. |
Moon
Moonrise for Friday, March 3 is at 2:14 p.m. and moonset occurs at 5:26 a.m. on the following day. Friday, March 3, the Moon will exhibit a waxing gibbous phase with 88% of the lunar disk illuminated. Full moon occurs on March 7, 2023, at 6:40 a.m.
International Space Station (ISS) Observing
There are several visible passes of ISS from St. Louis for the week of March 3. They occur during morning hours. The best passes for this week are listed below.
Catch ISS from St. Louis starting Friday, March 3
| Date | Starts | Max. altitude | Ends | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Time | Alt. | Az. | Time | Alt. | Az. | Time | Alt. | Az. | ||
| 06 Mar | -2.9 | 5:46:29 | 10 | NW | 5:49:44 | 47 | NE | 5:52:59 | 10 | ESE |
| 08 Mar | -3.6 | 5:46:53 | 10 | WNW | 5:50:10 | 55 | SW | 5:53:26 | 10 | SE |
| 09 Mar | -3.8 | 5:00:30 | 30 | NW | 5:01:59 | 79 | NE | 5:05:19 | 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°.
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 southwest at 6:30 p.m. on March 4, 2023. Credit: Stellarium, EG
This week, three naked eye planets are visible. Venus and Jupiter are found in the west after sunset. Mars is found overhead after sunset.
Venus
Venus is climbing out of the Sun’s glare as it starts another an evening apparition. Once high enough above the horizon, Venus will be a bright target in the west after sunset until August 2023 when it approaches inferior conjunction. This week, look for Venus in the southwest about 20 minutes after sunset. Venus sets at 8:24 p.m.
Mars
Mars now rises before sunset becoming visible once it is dark. Look for it overhead about 30 minutes after sunset. Mars sets by 1:59 a.m.
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. Jupiter now sets at 8:14 p.m.
James S. McDonnell Planetarium
Night Sky Update: March 3 – 11, 2023