It’s hard to follow up a month like August: every year the August night sky wows with the Perseids shower and a host of other astronomical events. But this year September does its best: the September night sky is full of interesting astronomical events.
This month you’ll be treated to a series of planet-gazing opportunities, a few other celestial objects, and of course the September equinox. Whether you’re new to stargazing or just seeking some of the other interesting astronomical sights, there’s plenty to see in the night sky in September.
Additionally, September signals a season change. This means your chances to see the aurora begin to shift hemispheres; it’s the perfect time to plan your trip to see the northern lights for those in the northern hemisphere.
Before jumping into the list, I want to provide some recommendations for telescopes and binoculars; some of the events this month will require having one if you want to see them. The link above includes guides to help you choose a telescope or binoculars at any level – from budget-conscious beginner to enthusiast willing to invest.
Ready to learn more about what you can see in the September night sky this year? Read on for 10 of the most interesting astronomical events in the night sky in September 2023.
This post was originally published in August 2018, and was updated most recently in August 2023.
September 1 – Peak of the Aurigid Meteor Shower
Auriga is one of my favorite winter constellations: its big bright stars are easy to spot in the sky. And while it’s not winter yet, Auriga is beginning to rise in the sky. With it comes its own meteor shower.
The Aurigid meteor shower is definitely a minor shower; its maximum rate (ZHR) is only about six meteors per hour. That said, if you’re out stargazing on September 1st, you might spot a few of them! The moon will be 92% illuminated and may pose interference to starting September with shooting stars; just be prepared and keep scanning the whole sky to see any you can.
September 4 – Conjunction of the Moon and Jupiter
Next up is Jupiter’s best viewing opportunity of the month; after sunset on September 4th, the Moon and Jupiter will appear close together in the sky. At their closest, they’ll be a mere 3°04′ apart – about the distance of the three stars in Orion’s Belt, for context.
It won’t be hard to spot either – the Moon will be 67% illuminated and Jupiter is always eye-catching – so this is a great event if you’re trying to stargaze with kids or love moon-gazing while out under the stars.
September 9 – Peak of the ε-Perseid Meteor Shower
September is not known for its meteor showers. Even those do that occur have a hard time comparing to the show the Perseids put on in August. Still, any chance to spot them is worth trying if the skies are clear!
On September 9th, you can try to spot ε-Perseids meteors. Despite their name, these meteors are likely not caused by the same comet (109P/Swift-Tuttle) as the August Perseids; instead, they simply appear to radiate from the same point in the night sky – which is how meteor showers get their names.
At their maximum, you can look for roughly 5 ε-Perseids per hour, coming from the general area of the constellation Perseus high in the southwest sky. Like we said – not as spectacular as Perseids, but still interesting!
September 18 – Venus at Greatest Brightness
Have you noticed it lately? Venus is real bright, y’all. You can’t say you haven’t seen it, if you’ve been up before the sun lately and looking eastward.
This is because Venus is reaching its greatest brightness on September 18th. This is the brightest Venus will be in the morning sky before it starts to swing back toward the Sun and eventually appear in the evening skies again.
September 19 – Neptune at Opposition
For those not familiar with the term “opposition,” it means that Neptune and the Sun will be opposite of on another (with the Earth in between, kind of like the alignment of an eclipse over huge distances). The Sun will brightly illuminate Neptune, making it a great time to view this planet
You will need equipment to see Neptune, which is small and extremely distant; be sure to review my recommended telescopes and binoculars to find something in advance. You’ll also probably need a star-finder app to spot Neptune, which is in the constellation Pisces.
September 23 – September Equinox
Early on September 23rd this year, the seasons officially changed. The September Equinox – called the “autumnal equinox” in the northern hemisphere and the “vernal equinox” in the southern hemisphere – signals the point where earth experiences roughly equal lengths of day and night.
While there is no night sky event to view for the equinox, it’s a cool time to consider our planet’s place in the solar system and how we orbit around the sun.
Learn more about the September Equinox and how it is marked in different parts of the world.
September 23 – Mercury at its Morning Peak
September is a big month for planetary viewing options, and the month winds down with the smallest and closest to the sun. Since Mercury is so close to the sun, we can only observe it when it reaches its “highest” aka visually furthest from the sun. This occurs cyclically as part of Mercury’s 88-day orbit; sometimes Mercury reaches its “peak” in the morning, then in the evening.
In any case, on the morning of September 23rd, you’ll be able to see Mercury about 16° above the eastern horizon just before sunrise. This is a great opportunity to head out and try to spot the smallest planet.
September 26 – Close Approach of the Moon & Saturn
After two close approaches in August, Saturn doesn’t appear near the Moon again until the end of September. Specifically, on the night of September 26th, the Moon and Saturn will appear within 2°25′ of each other in the night sky. As in August, the Moon will again be bright and using a telescope or binoculars will help reveal more wonders of both solar system objects.
Do you have questions or comments about these various astronomy events in the September night sky? Let me know in the comments!