9 Night Sky Events to See in September, From the Harvest Moon to Venus at Its Brightest
This month brings glowing planetary meetups, excellent Milky Way viewing, and the start of a promising season for northern lights.
August’s total solar eclipse will be tough to beat, but September offers its own impressive astronomical lineup. This month will see a host of planet-moon alignments, as well as the chance to see Venus at its most luminous.
September also marks the return of autumn in the Northern Hemisphere—and that means one of the best times for aurora sightings, as Earth’s equinox-timed tilt often comes with powerful northern lights shows.
Here’s what to watch for in September’s night sky, with details on where to look and when.
Moon-Mars Conjunction—September 6-7
The crescent moon and Mars will appear within roughly three degrees, or three pinky widths, of each other in the pre-dawn sky on September 6 and 7. Look for the duo above the eastern horizon around 3 a.m. local time. About 90 minutes later, Jupiter will rise in a diagonal line behind the two, with Saturn also visible in the southwest sky. The planets will stay visible until daybreak.
Moon Meets Jupiter—September 8
After the moon meets Mars, it will join up with Jupiter a few hours before sunrise on September 8. As in previous days, the pair will travel above the eastern horizon. Look skyward around 4 a.m. local time; they’ll remain visible until the sun rises.
(See Amazing New Pictures of Jupiter From NASA’s Juno spacecraft.)
New Moon—September 11-12
Stargazing nights are most impressive around a new moon, when our neighboring space rock produces virtually no lunar light. Pair this inkiness with a dark-sky destination, such as a national park, and you could see galaxies, nebulae, and the vivid center of the Milky Way galaxy. This month, the new moon occurs from September 11 to 12, and it’s worth heading out for. This is one of the last months in 2026 when we can see the Milky Way core in the Northern Hemisphere. After November, we won’t see it again until the spring.
Moon Nears Venus—September 14
The evening’s golden hour will look extra enchanting on September 14. Soon after our bright star sinks, the wisp of a crescent moon will appear within five degrees, or your middle three finger widths, of Venus above the western horizon. Unlike early September’s planet-moon meetups, this sight won’t require an early wake-up call. The pair will dazzle for around an hour after sunset before slipping beneath the horizon.
Venus Reaches Peak Luminosity—September 18
On the evening of September 18, Venus will reach its brightest magnitude for its entire 2026 evening apparition—and one of its most vivid points in the year. It will reach a magnitude of -4.8, which won’t look much different from the nights before or after. (For scale, the full moon is about magnitude -12.) That said, it’s still worth keeping an eye on. Due to its luminosity, Venus is one of the easiest sights in the sky to find, even in bright cities. It will appear just after sunset near the western horizon. Don’t miss Mercury beside it.
Autumn Equinox, and Aurora Activity Uptick—September 22
Fall in the Northern Hemisphere officially begins the evening of September 22, and leaf peepers, listen up: The Old Farmer’s Almanac says the northeast’s foliage could start turning soon after. And that’s not the only change to expect as the seasons turn. The equinoxes are also known to produce above-average northern lights activity.
(How to Photograph the Northern Lights, According to an Expert.)
It’s due to the tilt of the Earth at this time, which produces more favorable conditions for the solar wind. An increase in activity isn’t promised—auroras are tough to predict—but it does bring a wave of excitement to aurora season’s beginnings. And while the 11-year peak of auroral activity, known as solar maximum, may be over, this year could see impressive displays, too—particularly in Arctic latitudes.
Mars Joins Gemini Twins—September 25
The Gemini constellation is best known for its twin stars, Castor and Pollux. On the morning of September 25, this family will temporarily grow. Mars will align almost perfectly with the twins, creating an easily recognizable trio in the eastern sky, with Castor at the top, Pollux in the middle, and orange-tinged Mars below. Look further down the sky to see bright Jupiter near the horizon, too.
Full Harvest Moon—September 26
Watch for the full moon as it rises the evening of September 26. The orb, known as the full harvest moon, will reach peak illumination just before 1 p.m. ET. It’s best to watch it as it rises around sunset, or sets around sunrise. It appears largest and most luminous near the horizon because of an optical trick known as the moon illusion. At this time, it may also look especially orange.
(Phases of the Moon, Explained.)
The full harvest moon isn’t traveling solo. Saturn will follow the moon soon after its rise. The duo will move together, within six degrees of each other, throughout the night. Those with telescopes may see Neptune nearby, too.
Andromeda Galaxy—All month
Spy deeper into space with one of the best targets of the month, the Andromeda Galaxy. It’s the closest major galaxy to the Milky Way. Andromeda, a spiral galaxy like our own, is most visible under inky, remote skies. You can see it with the naked eye as a faint smudge, but it’s more impressive with binoculars or a small telescope. Look for it throughout the night; it’s most visible when it’s highest in the sky, around midnight or 1 a.m. local time.
