Each month, I pick out North America’s celestial highlights for the weeks ahead (which also apply to mid-northern latitudes in the Northern Hemisphere). Check my main feed for more in-depth articles on stargazing, astronomy, eclipses and more.
September ushers in a season of dramatic celestial events, from Saturn at opposition and some close planetaring pairings to a spectacular “blood moon” total lunar eclipse — though the latter is not visible in North America. As days shorten ahead of the autumnal equinox, stargazing becomes an evening activity, and a rewarding one as the constellations rise and fall with the changing of the season up above. Here’s everything you need to know about stargazing in September 2025.
1. The ‘Autumn Star’
When: all month
Where: southern night sky
Fomalhaut, the “Autumn Star,” is the brightest star in Piscis Austrinus, and visible from mid-northern latitudes only in autumn. Fomalhaut sits low in the south, so spotting it requires a dark southern horizon.
2. Full Corn Moon And Total Lunar Eclipse
When: during dusk on Sunday, Sept. 7, 2025
Where: eastern horizon
The best time to watch September’s full moon rise in North America will be at moonrise at dusk on Sunday, Sept. 7. This year it carries the Corn Moon name, not the common Harvest Moon name, because October’s full moon is closest to the equinox on Sept. 22. While Asia, Australia, and parts of the Pacific will see a total lunar eclipse, no part of the eclipse will be seen from North America.
3. ‘Great Square’ of Pegasus
When: after dark all month
Where: eastern horizon
The Great Square is a classic sight in the fall night sky. Look above east after dark for four bright stars, which are easy to spot in urban skies thanks to their brightness and distinctive shape. They form the core of the constellation Pegasus. This asterism’s arrival signals seasonal change and the approach of the September equinox.
4. Moon And Saturn
When: after dark on Monday, Sept. 8, 2025
Where: eastern sky
Tonight, a 97%-lit waning gibbous moon appears beside golden Saturn in Pisces. Saturn is near its brightest for the year ahead of its Sept. 20 opposition, but you’ll need a small telescope to glimpse its ring pattern.
5. A ‘Diamond’ In The Sky
When: before sunrise on Tuesday, Sept. 16, 2025
Where: eastern sky
Before dawn, a slender 28%-lit waning crescent moon appears near Jupiter, with the bright stars Castor and Pollux of Gemini to its left. Together they form a neat diamond shape, each point about four degrees apart.
6. Moon, Venus And Regulus Align
When: before sunrise on Friday, Sept. 19, 2025
Where: eastern sky
A mere 6%-lit crescent moon joins Venus and Regulus in a tight, half-degree grouping just above the east-northeast horizon about an hour before sunrise. This is one of the month’s best naked-eye conjunctions.
7. Saturn At Opposition
When: Sunday, Sept. 21, 2025
Where: eastern sky
Tonight is the best night of the year to view Saturn (though in practice, any time this month is good). At opposition, it rises at sunset, sets at sunrise, and shines at magnitude 0.6. Through a small telescope, Saturn’s rings will be nearly edge-on but still visible.
8. Partial Solar Eclipse
When: Monday, Sept. 22, 2025
Where: Southern Hemisphere
The new moon at 2:54 p.m. EDT ensures the darkest skies of the month, and in some parts of the world also causes a partial solar eclipse. Observers in New Zealand, Fiji, Tonga, and Antarctica will see a partial solar eclipse at sunrise, with the moon covering up to 79% of the sun.
9. Fall Equinox
When: Monday, Sept. 22, 2025
Where:
At 2:20 p.m. EDT today, it’s the fall/autumnal equinox. It marks the point when the midday sun is directly above the equator, with everywhere on the planet getting (roughly) 12 hours of daylight and 12 hours of darkness. Today, the sun will rise due east and set due west. From this point on, nights will get longer.
10. Northern Lights
When: for two weeks after Monday, Sept. 22, 2025
Where: northern sky
Thanks to Earth’s axis being side-on to the solar wind, the Northern and Southern Lights are most intense around the equinoxes. However, there’s a slight lag factor, making the few weeks after Sept. 22 reliably the best time for aurora displays — though nothing is guaranteed.
11. The Andromeda Galaxy
When: after dark all month
Where: eastern sky
After dark, look to the northwest for the constellation Cassiopeia’s “W.” From the rightmost “V,” trace a line down to the bright star Mirach in Andromeda. About two-thirds of the way from Mirach toward the horizon is the Andromeda Galaxy (M31), the farthest object visible to the naked eye at 2.5 million light-years away (though you’ll need a very dark sky far from lights). Even from a city, 10×50 binoculars will show it as a fuzzy patch.
The times and dates given apply to mid-northern latitudes. For the most accurate location-specific information, consult online planetariums like Stellarium.
Wishing you clear skies and wide eyes.
