This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Sunday, June 1, 2025.
Information updated weekly or as needed.
Times given as local St. Louis time this week will be in Daylight Saving Time. 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. Times posted in the Night Sky Update are in the 24-hour format.
Join us for our next star party, Friday, June 6, 2025, held in association with the St. Louis Astronomical Society.
Observing Highlight of the Week
On May 31, 2025, A strong M8.1 solar flare was produced by sunspot 4100. The long lasting solar flare trigger a fast moving CME that arrived at Earth on June 1, 2025. In this image, the bright region near the center of the Sun is sunspot 4100 actively flaring. Image credit: NASA, SDO/AIA.
There is a chance for auroras to be seen from mid to low latitude areas starting on June 1, 2025. The geomagnetic storms that are expected to occur over the next few days will be subsiding by June 3, 2025. It is not often we get a chance to see auroras this far south, but it remains a possibility over the next few days.
Auroras are possible over the new few days due to a M8.1 solar flare on May 31, 2025, which triggered a strong Earth facing coronal mass ejection. Scientist suggest this fast-moving CME is moving at a rate of 4.3 million mph. The CME has already reached Earth leading to G3 and G4 level geomagnetic storms. Auroras were visible from northern Missouri during early morning hours on June 1, 2025.
As of this writing, the geomagnetic storm is beginning to subside, however this could change again later on June 2, 2025. Your best chance of seeing auroras will be to travel to the darkest skies you can that provide a clear view to the north. If they become visible, you are likely to see the high-altitude component of the display which appears red due to oxygen being excited by charged particles from the Sun. If the storm is strong enough there is a chance we could see some yellow and green color in the display. These colors are produced at lower altitudes by excited oxygen atoms in our atmosphere.
If you plan to drive to a dark location, make sure to visit the Space Weather Prediction Center website for current space weather conditions.
This image recorded with the LASCO 3 camera aboard SOHO shows the fast moving CME produced by the solar flare from sunspot 4100 on May 31, 2025. Image credit: NASA, ESA.
T CrB Nova Update 6/1/2025
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 midnight, the constellation Corona Borealis will be found high in the eastern sky. 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. Current magnitude of the system is 10.2.
The Sun and Moon
The Moon as seen from the International Space Station, on July 31, 2011.
Credit: NASA
Sun
Sunrise is at 05:38 on Sunday, June 1 and sunset is at 20:20 providing close to 15 hours of daylight. Even after sunset, light from the Sun will dimly illuminate our sky for about 2 hours. This period is called twilight, which ends around 22:15 this week. For those with a sundial, local noon occurs around 12:59 on June 1, 2025.
Moon
Moonrise for Sunday, June 1, is at 11:18 and moonset occurs at 01:16 the following morning. On June 1, 2025, the Moon will exhibit a waxing crescent phase with 35% disk illumination. By June 9, 2025, the Moon will exhibit a waxing gibbous phase with 97% disk illumination. First quarter moon occurs on June 2, 2025, at 22:41 CDT.
International Space Station (ISS) Observing
There are no visible passes of ISS from St. Louis for the week of June 1. ISS will return to morning skies for us on June 19, 2025.
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 south at 20:45 on June 1, 2025. Credit: Stellarium, EG
Looking east at 04:50 on June 2, 2025. Credit: Stellarium, EG
Three naked eye planets will be visible this week. Mars is visible after sunset once it is dark in the west. Venus and Saturn are visible before sunrise in the east.
Venus
Venus is found in the east before sunrise for the rest of the year. It currently rises around 03:30. Look for Venus in the east around 04:30 as it clears tree lines.
Mars
Look for Mars high in the western sky after sunset. Mars has shifted into the constellation Leo. The current apparition of Mars will continue throughout the rest of 2025. Watch for the Red Planet as it shifts westward through the year. Mars sets around 00:49.
Jupiter
Jupiter is becoming difficult to spot this week. 20 minutes after sunset, Jupiter will only be 7° above the western horizon. For most of us, trees will make finding the planet difficult. Jupiter reaches superior conjunction on June 24, 2025.
Saturn
Saturn can be found in the east before sunrise. Around 03:45, Saturn will appear roughly 15° above the eastern horizon. Saturn rises this week around 02:27.
Our next Star Party will be held on Friday, June 6, 2025, from 6:30 pm until 9:30 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 June 6, join us indoors in our planetarium theater for a monthly lecture.
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: June 1-9, 2025
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