September is the Autumnal Equinox — the beginning of fall — in the Northern Hemisphere. Here’s a look at “What’s up in the sky” in the D.C. region this month.
“What’s up in the sky?” is a recurring feature and publishes on the first of every month. You can find it on WTOP’s The Space Place. Email Greg your space questions and he might answer them in the next edition.
Let’s get to the sky for September 2025!
Must-see sky sights for September
During September 2025, Venus continues to be the “Morning Star” in the east before dawn, albeit lower in the sky, but still bright. The beautiful and bright winter constellations keep Venus celestial company.
September is the Autumnal Equinox — the beginning of fall — in the Northern Hemisphere.
The Northern Lights may be visible from parts of the D.C. region on the first two nights of the month.
The zodiacal light will be visible in the eastern predawn sky for about two weeks starting on Sept. 19.
The moon has some beautiful close pairings with stars and planets.
Star of the month: Polaris
In September and every night of the year and anywhere above Earth’s equator, Polaris marks almost true north. Polaris can be seen in cities and everywhere on the planet that is near or above the equator. Its parent constellation Ursa Minor — Little Bear — rotates around Polaris, as does the whole northern sky. Just face north and look up.
Highlights of the month
As we go through September, each night in the south-southwest of our galaxy, the Milky Way is absolutely resplendent and sprawling as it flows across the sky to the northeast.
You need a dark sky site to see the Milky Way at its best. As September begins, the Milky Way is well up in the sky after dark and the “Summer Triangle” is nearly overhead. As the night heads into the hours before dawn, the “Winter Milky Way” is visible in the southeast to the northeast. You can image the Milky Way with a smartphone and/or camera by taking time exposures. For best results, use a tripod.
Sept. 1: The National Oceanic and Atmospheric Administration said there is a category G3 geomagnetic storm possible on Sept. 2 and a G2 category storm on Sept. 1. For the D.C. region, the two-day aurora forecast and our forecast partly cloudy skies mean we may detect aurora to the north.
Sept. 1: Predawn eastern horizon: Venus is very near the Beehive Cluster. Mercury and the star Regulus keep each other company just above the predawn horizon around 5:30 a.m. local time.
Binoculars will really help you see these two events.
You can also see Jupiter high above Venus to form a line of three predawn visible planets.
Sept. 7: The full corn moon is at 2:09 p.m. and rises at sunset in the east. This is the last full moon of summer.
Sept. 13, 14: The star Spica and Mars meet in the west-southwest in twilight. The attraction lies in seeing the color contrast between the reddish Mars and the icy blue Regulus. Binoculars will really help you see these two and their color.
Sept. 19: A must-see in the predawn sky in the east is the very old waning crescent moon with Earthshine joining up with Venus and the star Regulus. Try taking a smartphone/camera pic.
Sept. 19: For about two weeks, the Zodiacal Light will be visible in the northern hemisphere in the eastern predawn sky and in the southern hemisphere in the west after sunset. You will need a dark sky site and a clear horizon to see this ghostly pyramid shape in the sky. Try taking a smartphone/camera pic.
Sept. 21: Saturn at opposition — see planets section below.
Sept. 22, 2:19 p.m.: Autumnal Equinox — the beginning of Fall — in the Northern Hemisphere and Spring in the Southern Hemisphere.
Sept. 23: Neptune at opposition — see planets section below.
Sept. 27: Right after dark, look to the southwest to see the young waxing crescent moon near Antares and the Milky Way. Try taking a smartphone/camera pic.
The moon
Sept. 7: Full corn moon — Total lunar eclipse Eastern Hemisphere. Not visible in the Americas.
Sept. 14: Last quarter
Sept. 21: New moon — Partial solar eclipse Southern Hemisphere. Not visible in the Americas.
Sept. 29: First quarter
Planets
Mercury is very low on the eastern horizon on Sept. 1 but is soon lost in the sun’s glare.
Venus is bright but lower above the eastern horizon before dawn, you can’t miss it.
Mars will be low in the western sky at twilight and will be getting closer to the glare of the Sun at month end.
Jupiter rises in the northeast around 2:30 a.m. local and is quite bright.
Saturn rises in the east as it gets dark and on Sept. 21 is opposite the sun, rising at sunset. A great view in a telescope as the rings cast a thin line across the planet.
Uranus is in the eastern sky well after dark.
Neptune rises in the east as it gets dark and on Sept. 23 is opposite the sun, rising at sunset near Saturn. You need a telescope to observe the planet.
Pluto is way out there in the solar system and requires taking images through a telescope spaced days apart to hunt it down.
DC-area events
Shenandoah National Park
- Shenandoah National Park’s Big Meadows is an excellent dark sky site and there are a variety of activities for you to enjoy throughout the Park. I will be conducting my “Let’s Talk About Space” events, so hope to see you there. If you visit Shenandoah National Park, be sure to check out the rangers’ schedule as they host astronomy events as well.
NOVAC General Meeting
The Analemma Society
- The Analemma Society is pausing operations and work with Fairfax County Park Authority regarding Friday Night Public Viewing Sessions at Turner Farm in Great Falls, Virginia, temporarily. Check its calendar for other astronomy activities in September.
Smithsonian National Air and Space Museum
- The museum has loads of astronomy stuff in D.C. and Chantilly for September.
Other groups holding events in September include Virginia State Parks and the National Capital Astronomers.
You can check here and here for astronomy clubs that are outside the D.C. area.
Bonus!
Download NASA’s 2025 Science Calendar that features out-of-this-world pictures and information.
The Planetary Society’s Space Events 2025 Calendar is another resource for tracking space missions.
Use this useful tool to create a custom star chart for your location to help you find your way around the stars.
You can also send in any space-related questions to my email address. Suggestions about this feature are also welcome.
Follow Greg Redfern on Facebook, Bluesky and his daily blog to keep up with the latest news in astronomy and space exploration.
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