What to See in The Autumn Sky

Autumn is a superb time for viewing some of the planets furthest from Earth – the gas giants as they are known. There is the opportunity to see meteor showers and even a brand new comet. Our night sky expert Geoffrey Lindop gives us some background, the best viewing dates and photo tips for making the most of the autumn skies.

Mention the word ‘planet’ and many people think of the most beautiful of all the planets, Saturn, the planet with the rings. While once Saturn was thought to be unique with its rings, today spaceprobes have shown Jupiter, Uranus and Neptune also have rings. These four planets are known as ‘gas giants.’ And as the term suggests they are big – Neptune, the smallest of the group, is 17 times as massive as the Earth. Saturn is larger still having a mass 95 times that of the Earth. It has at least 146 moons, many of which have a tidal effect on the rings. These help maintain their beauty by shepherding the ring particles out of the gaps between the individual rings.

Saturn is at its closest to the Earth in the morning of September 8^th – it takes more than 29 years to complete one orbit of the Sun, and during August the Earth has been catching up with it. So on 8^th September the Sun, the Earth and Saturn are in a perfect line. A small telescope is required to see the ring system. A mobile phone camera can capture Saturn close to the Moon on September 16th and 17th, October 14th, and November 10th. For a truly stunning picture try placing one of the many monuments, castles, or landscape features, so plentiful in our region, into your shot.

September is also the best time to spot Neptune – 21^st September is the best day. It can be seen throughout the night in the constellation of Pisces.  Binoculars, or better still a small telescope is required, since it is too faint to be seen with the unaided eye. Or perhaps book a place in one of our three public observatories, in Moffat, Galloway Astronomy Centre south of Wigtown, and the Kielder Observatory. Any day during September both planets will be well placed so your visit to any of the observatories will be rewarding.

Uranus, the planet that orbits the Sun between Saturn and Neptune, can be seen with the naked eye. It will be closest to the Earth on 17 November, when it will be 18 times further away than the Sun. The planet is so faint that it was unknown as a planet before the 18th century, although its location was recorded as early as 128 BC by Hipparchus, who without the luxury of a telescope, still noted it in his star catalogue. But it was William Herschel who in March 1781 clearly saw the disc object and initially assumed it was a comet, later realising it may be a planet. Herschel named it George’s planet, hoping to impress King George III. The name stuck for 70 years before the planet was renamed Uranus.

Jupiter, the other gas giant, is big. If it were put on one side of a pair of imaginary scales, and all the other planets in the Solar System on the other side, then Jupiter would still outweigh them. Its position for viewing may not be as good as the other three gas giants but it is brighter. You will find it in the eastern sky before dawn. There is a good photo-opportunity on September 24th when it will be close to the last quarter Moon in the constellation of Taurus. Again on November 17 it will be close the full Moon. The Moon on that occasion will look a bit larger than normal, as it will be closer than usual to the Earth – they call it a supermoon.

October is a good month to see shooting stars. Astronomers call them meteors, and they are the debris left by comets, which burn up in the atmosphere when the Earth passes through their orbits. The Orionids can be seen between October 16 and 27, with the maximum display on October 20. The Taurids can be seen between October 20 and November 20.

A comet has been described as a dirty snowball. Dust and grit left over from the formation of the Solar System is mixed with a high proportion of water-ice. They normally live at the outer edge of the Solar System, but gravitational tides from passing stars, or the alignment of planets causes some of them to migrate towards the Sun. When they do, some enter a new orbit that brings them back to the inner Solar System. When they are close to the Sun material is blown off their surface. It is that material that has its own orbit around the Sun, that the Earth passes through producing meteors.

A newly discovered comet will grace our skies from October 23rd onwards. Comet Tsuchinshan-ATLAS was discovered in February 2023 by the Tsuchinshan Observatory in China and also by ATLAS, the Asteroid Terrestrial-Impact Last Alert System. It is likely to be bright enough to see seen with the naked eye.

You can learn more with our Top Tips for stargazing and be sure to visit our Dark Skies section for all the information and inspiration you need to plan your next visit.

Geoffrey has written a guide to the night sky to assist visitors in the South of Scotland, available to purchase at various locations or directly from the publisher.

We are grateful to Geoffrey for also producing a monthly night-by-night guide to the skies above us, so you can check out what there is to see throughout the upcoming autumn months. This is Geoffrey’s final installment, completing our look at what to see in the night sky through the seasons.