What's in the night sky in September 2023What to see in the September night sky including Moon phases, September Equinox, planet guide, star cluster M22 and M28, and galaxies M31 and M33.
September Moon Phases
September's full moon is so called the Harvest moon because this is when crops are gathered at the end of the summer season. At this time, the Moon appears particularly bright and rises early, letting farmers continue harvesting into the night.
Full Moon and New Moon for September 2023
September 2023 Full MoonThu 1st Jan
September 2023 Last QuarterThu 7th Sep
September 2023 New MoonFri 15th Sep
September 2023 First QuarterSat 23rd Sep
Notable Events in September
September 23rd is the September Equinox. The September equinox occurs at 06:43 UTC. The Sun will shine directly on the equator and there will be nearly equal amounts of day and night throughout the world. This is also the first day of autumn (autumnal equinox) in the Northern Hemisphere and the first day of spring (vernal equinox) in the Southern Hemisphere.
September Planets
On 22nd September Mercury will be at its third and final elongation of the year. At magnitude -0.4 it should be bright enough to pick out, although there are no nearby markers this time. 30 minutes before sunrise, look east to spot Venus. To the lower left of Venus is Regulus and follow that line for the same distance to Mercury.
Jupiter is a splendid object visible in the southern sky as soon as darkness falls, and on September 26th Jupiter reaches opposition, making it appear its brightest and most illuminated. Using higher magnifications you will see the yellowish flattened disc and as the four Galilean satellites. You should be able to follow the movement of these moons from night-to-night. It will be visible in the mornings from January to May, evenings from May to November, and mornings again from mid-December to the end of December.
Saturn is visible in the mornings from late January to early July, then in the evenings from July to December.
Neptune will be at opposition on the 19th. It will be at its closest to earth and brightest at this time, however you'll still need binoculars or a telescope to spot it.
September Meteor Showers
There are no notable meteor showers in September.
September Deep Space Objects
As the warm nights of summer give way to crisp autumnal evenings, there's plenty of autumn deep sky objects to see in the night skies. We take a look at some of the top sights to see during autumn.
M22 is the third brightest star cluster visible in the northern hemisphere and is known to contain at least 75,000 stars. Its low altitude means that it is often overlooked, but at magnitude +5.1, it is a naked eye object and a fine target for small telescopes. It is fairly easy to see in the low southern skies in the constellation of Sagittarius, approximately half way from Nunki to µ Sgr. M28 lies nearby, and although lower again
The Andromeda Galaxy (M31) and Triangulum Galaxy (M33) are the real showpieces of the autumnal skies. Both are visible to the naked eye from dark sky sights, and both fine binocular targets. A small telescope will show M31's satellite galaxies M32 and M110, as well as the galaxies dust lanes.
You can find M33 by following the line from the star Mirach to Upsilon Andromedae, and extending it about the same distance in a straight line.
M33 can be found just less than two-thirds of the way between the stars Hamal in Aries, and Mirach in Andromeda. Through a small telescope, it will appear as a faint, oval shaped patch of light, while larger telescopes should be able to pick out more detail under dark skies.
