This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Saturday, June 14, 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 June 1, 2025, while the Sun was still about 15° above the horizon, smoke particles from Canadian and US wildfires caused the Sun to appear more red than it normally would. The image was taken from Twin Oaks, Missouri. Image credit: Eric Gustafson.
With wildfire season well under way, you may notice the sky seems a little different these days. From milky blue daytime skies to muted sunset colors, viewing conditions for much of North America has been affected by wildfires in Canada and the US. While sky conditions are the least of concerns when human lives and the environment are being impacted, understanding these viewing conditions can help us understand some of the dangers we face with poor air quality.
The U.S. National Interagency Fire Center has predicted fire risk will be above average for portions of western Canada, California and the northwestern US. Throughout wildfire season we should expect smokey conditions for a large portion of North America. This is a concern for all, but it is especially concerning for anyone with respiratory issues.
The Air Quality Index is the EPA’s index for reporting air quality to the public and institutions around the country. AQI sensors around the country measure the amounts of various air pollutants, which include smoke particles, that are present at a given moment. As air conditions are logged, the AQI presents current conditions with one of 6 different categories.
The table above shows the AQI index showing corresponding index values with cautionary statements. Table credit: EPA.
As an observer, you can visually check on these conditions during daytime and twilight periods. During the day, the sky looks blue to us because our atmosphere scatters sunlight as it passes through due to Rayleigh Scattering. This blue appearance will vary depending on the amount of air pollutants present at a given time. When the AQI value is low, indicating lower amounts of air pollutants, the sky will have a vivid blue appearance. As the value of air pollutants increases, the deep blue will shift towards a milky blue appearance.
The appearance of the Sun is also impacted by the volume of smoke particles in the atmosphere. Last week many of you likely noticed the Sun appeared red well before it was setting. When the Sun is low to the horizon, its appearance is already shifting towards red due to increased atmospheric scattering. Add in high volumes of smoke particles, you do not have to wait for sunset for the Sun to appear red. As wildfires continue this year, we will continue to see our skies affected.
If you are interested in checking on smoke conditions for your area, there are a few resources you can visit. For a forecast of smoke, you can check firesmoke.ca. This is a Canadian service that will forecast smoke movement based on current weather systems. For current fire conditions I would check the resources available at the National Interagency Fire Center.
Titan Shadow Transit 6/16/2025
Titan’s next shadow transit occurs on June 16, 2025. The transit begins at 03:21 CDT and ends at 09:00 CDT. From St. Louis we will only see about 1/3 of the transit as it is still underway after the Sun rises. Around the start of the transit, you will find Saturn about 22° above the eastern horizon at 111.5° azimuth.
You will need a telescope to see Titan’s shadow transit across the clouds of Saturn. While the transit is under way, you will also see Titan to the east of Saturn and possibly the moon Rhea a little west and north of the planet. Saturn’s rings will still appear thin however we are starting to see the underside of the ring system. If you would like to plan for future transits of Titan’s shadow make sure to read Bob King’s article on Sky and Telescope which can be found here.
Image created using Stellarium
T CrB Nova Update 6/14/2025
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 05:36 on Saturday, June 14 and sunset is at 20:27 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 22:25 this week. For those with a sundial, local noon occurs around 13:02 on June 14, 2025.
Moon
Moonrise for Saturday, June 14, is at 23:30 and moonset occurs at 09:32 the following morning. On June 14, 2025, the Moon will exhibit a waning gibbous phase with 88% disk illumination. By June 22, 2025, the Moon will exhibit a waning crescent phase with 10% disk illumination. Last quarter moon occurs on June 18, 2025, at 14:19 CDT.
International Space Station (ISS) Observing
Visible passes of ISS from St. Louis for the week of June 14 occur during morning hours. The table below lists the best of these passes. 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 west at 21:15 on June 14, 2025. Credit: Stellarium, EG
Looking east at 04:30 on June 15, 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 03:17. Look for Venus in the east around 04:30 as it clears tree lines.
Mars
Look for Mars in the western sky 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. Mars sets around 00:16. This week you will find Mars near the bright star Regulus. If you watch Mars, you will see it pass by Regulus as the week progresses. This is a great opportunity to see that planets are moving.
Saturn
Saturn can be found in the east before sunrise. Saturn rises around 01:42 this week. The planet should be high enough to see by 02:30. If you have a telescope, you can see Saturn’s moon Titan cast its shadow on the cloud tops of Saturn on June 16, 2025.
Our next Star Party will be held on Friday, August 1, 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 our free monthly sky 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 14-22, 2025
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