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◼ Welcome to your guide to the night sky in October. Venus lies in the evening sky, but remains low in twilight from northern latitudes, though high in the sky from the southern hemisphere. Mercury will make a favourable appearance for northern hemisphere observers in the latter part of October. Jupiter and Saturn are both bright in the evening sky. Here’s what else you can see in October’s night sky!
October’s star chart
Click on the image above, or the following text for an interactive map of constellations visible in the sky, showing you the night sky in September. It can be adjusted for any time and date.
We also have a map of the night sky set up for mid-latitudes in the southern hemisphere.
The stars in October 2021
For countries in the northern hemisphere, the nights are getting longer now with more hours of darkness in which to enjoy the stars.
By mid evening, the familiar asterism of the Plough, or Big Dipper, which is part of the constellation Ursa Major, is reaching its lowest point in the sky, due north. Almost opposite it, on the other side of the North Celestial Pole, Cassiopeia is rising to its highest point, followed by Perseus and Auriga, with its brilliant star Capella. Perseus is a constellation with some fine sights including the Double Cluster and a famous eclipsing variable star, Algol.
The Summer Triangle, made up of the bright stars Vega in Lyra, Deneb in Cygnus, and Altair in Aquila, is beginning to sink in the west. Despite its name, this feature will be easily seen in evening skies until winter, from northern hemisphere locations.
The Great Square of Pegasus is winging round to the southern part of the sky. Stretching from the square’s upper left corner is the constellation of Andromeda, with the bright galaxy M31 easily seen with binoculars in a dark sky. Not far below Andromeda, as seen from northern latitudes, you can find a smaller galaxy, Triangulum, that is home to another nearby galaxy, M33.
To the east, Taurus is now rising, its compact cluster of the Pleiades, or Seven Sisters, a reminder that winter is on its way.
Pegasus and the Summer Triangle can also be seen from much of the southern hemisphere during October evenings. From such locations, Crux, the Southern Cross is now low in the south, with bright stars Alpha and Beta Centauri trailing behind it. High to the north can be found Aquarius and Capricornus. Lower to the northeast you will see Pegasus. Our Milky Way’s companion galaxies, the Large and Small Magellanic Clouds are rising in the south east as they closely circle the South Celestial Pole.
The planets in October 2021
The innermost planet makes one of its best appearances of the year for northern skywatchers in October. During the third week of the month, it moves out into the pre-dawn twilight, getting more than 5 degrees high in the east during the last week of October, before the sky becomes too bright, reaching magnitude -0.8,. Greatest Elongation West occurs on the 25th when Mercury will lie 18 degrees from the Sun. The planet will be less easy to see from mid latitudes in the southern hemisphere.
Venus remains a splendid sight as evening star for those at more southerly latitudes, standing high in the western sky and shining at a brilliant magnitude -4.4. The crescent Moon passes Venus on 9 September, and the planet will lie close to first-magnitude star Antares in Scorpius on the 16th and 17th.
Venus is less easy to spot from northern latitudes, as it never gets very high above the south-western horizon. If you have a clear, unobstructed horizon, however, its brilliance will reveal its presence in the fading twilight.
We have a special article about this apparition of Venus, and how it will appear during 2021.
Mars is lost to view this month, lying too close to the Sun in the sky. It reaches Conjunction, when it will lie on the far side of the Sun, on 8 October, after which it technically moves into the morning sky.
Read our extensive guide to Mars.
The largest of the planets, Jupiter dominates the evening sky as soon as it gets dark. During the evening will see it shining at a bright -2.7 “star” swinging from the southeast to the south, and sharing the constellation of Capricornus with fellow gas giant Saturn. Jupiter does not set until after midnight for most of October. The gibbous Moon will lie close to Jupiter on the night of the 15th.
Jupiter is still a very prominent object for southern hemisphere stargazers, shining much higher in the sky for a longer part of the night.
If you have binoculars or a telescope, you can easily see the four brightest satellites of Jupiter, the Galilean moons Io Europa, Ganymede and Callisto. A telescope will also reveal the belts and bands in Jupiter’s cloud tops.
A brilliant flash was observed in the clouds of Jupiter in September due to an impacting asteroid or comet, but it left no detectable scar.
The ringed planet, another gas giant, was also at Opposition last month. Like Jupiter, it is now a prominent object in the evening sky, shining at around magnitude 0.3, like one of the brightest stars, and with a yellowish light. It sets after midnight at the start of October, but an hour or more earlier by the month’s end. For northern hemisphere observers, Saturn remains low in the sky, in the constellation of Capricornus, though it will steadily head north over the coming years.
From the southern hemisphere, Saturn will rise high in the sky, and so this will be an ideal time to observe it. The gibbous Moon will lie close to Saturn on the night of the 14th.
Read more about Saturn.
The closer of the ice giants, Uranus lies in the constellation of Aries, where it shines at magnitude 5.7. At the start of October the planet rises in the east by mid-evening as it heads for Opposition in early November when it will be visible all night. Though theoretically visible with the unaided eye when at a high elevation, under clear dark skies, you will practically need binoculars or a small telescope in order to spot it. Uranus is bright enough to be easy to record with a camera and a short time exposure of a few seconds.
Read more about Uranus.
Neptune reached Opposition in September in Aquarius, so is now well placed for viewing throughout the evening. It shines at magnitude 7.8, so you will need binoculars to see it. A telescope may help you see this ice giant’s tiny disk, just 2.4″ in diameter.
Read more about Neptune.
Meteors from Halley’s Comet
One of the year’s more reliable meteor showers, the Orionids, can be seen in October. These “shooting stars” are dust left by Halley’s Comet and one of two annual showers from that comet. The official limits of activity for the Orionids are from October 2 to November 7, with the peak occurring on the night of October 22-23. Rates seen for a single observer under ideal conditions are expected to be around a moderate 20 meteors per hour, so observing around the peak date will give you the best chance of seeing anything.
On the night of maximum, the shower’s radiant, in the club wielded by mighty hunter Orion, rises at around 10pm local time from mid-northern latitudes. You won’t see any Orionids before then when it is below the horizon. Unfortunately, in 2021 the Moon will be just two nights past Full, so will shine as a bright gibbous phase, making this a less favourable year to catch the fast moving streaks that are the Orionids.
Related: About the Orionid meteor shower
Look out for asteroids Ceres and Pallas
October is a great month to find one of the dwarf planets, Ceres, which was the first asteroid to be discovered. Over the course of this month it brightens from 8.3 to 7.7 as it heads for Opposition in November. Ceres should be easy to find with binoculars as it lies close to the V-shape of the Hyades star cluster in Taurus, heading towards the bright, first-magnitude star Aldebaran (alpha Tauri) as October progresses. Read our full guide to seeing Ceres.
Pallas, which was the second asteroid to be discovered, was at opposition on 11 September, when it reached a magnitude of 8.5. It fades to 9th magnitude during October, so you will need binoculars or a small telescope to find it, as it continues its journey through Aquarius. See our special guide to seeing Pallas for yourself.
The Moon always makes a great target for a small telescope, which come into view as its phases change. We’ve a guide to where to find 50 of the best lunar features, plus a checklist to download so you can tick them off as you spot them! Don’t have a telescope? Here’s our guide to choosing one.
Fifty fantastic features – our amazing Moon
Here’s our guide to observing some of the finest sights on the Moon with small telescopes. Our pages of charts will help you find interesting features to seek out yourself, including craters, lava flows, mountain ranges and deep chasms!
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