All About Space

The autumn night sky

As the leaves begin to fall from the trees, the summer constellat­ions give way to those of the cooler months


Moving upwards, away from the summer constellat­ions of Cygnus and below, the Milky Way begins to lose some of its lustre as it starts to thin out compared to the densely star-packed region around the galaxy’s centre. It is still impressive to see though, especially if you can get out to a dark-sky site in order to observe this shimmering belt of stars.

During autumn our Milky

Way moves through the constellat­ions of Perseus, Cepheus (the King) and Cassiopeia (the Vain Queen).

Not all of the constellat­ions of summer have disappeare­d though – the likes of Cygnus and Aquila are still on show, offering observers in the Northern Hemisphere a selection of summer nebulae and star clusters. Autumn is the time to seek out open star clusters in our galaxy, which glow extremely brightly like gems in the night sky.

Astronomy is best done under night skies untouched by light pollution and on a Moonless night, but if you’re an urban dweller who is unable to get out to the countrysid­e, open clusters are still easily visible from locations of moderate town haze. Star clusters stand out much better than fuzzy and often dim nebulae. Not only that, but the Milky Way laces through constellat­ions that are high up in the sky, meaning that you won’t need to peer through a horizon touched by artificial lighting in order to get a good look at our galaxy.

6 Messier 52

Constellat­ion: Cassiopeia

Right Ascension: 23h 24m 48s Declinatio­n: +61° 35’ 36” Magnitude: +6.9

Minimum optical aid: 10x50 binoculars

This open cluster displays one of the biggest problems of the Milky Way. Because we’re looking into the galaxy’s spiral arms, which are full of dust, the light of objects in the Milky Way can be dimmed by that dust, which makes it hard to calculate their distance. Open cluster Messier 52 lies between 3,000 and 7,000 light years from us, but even though interstell­ar dust is blocking some of the light, it’s still an easy binocular object.

7 Messier 103

Constellat­ion: Cassiopeia

Right Ascension: 01h 33m 20s Declinatio­n: +60° 42’ 00” Magnitude: +7.4

Minimum optical aid: Four-inch refractor or five-inch reflector

Another open cluster, Messier 103 contains about 40 stars, including a red giant, which is an evolved star reaching the end of its life. This is a very rare sight in an open cluster of young stars. To find M103, locate the bottom-left star of Cassiopeia’s

‘W’, called Ruchbah, or Delta Cassiopeia­e, and the cluster is about a degree northeast.

8 Messier 34

Constellat­ion: Perseus

Right Ascension: 02h 42m 10s Declinatio­n: +42° 46’ 00” Magnitude: +5.5

Minimum optical aid: 10x50 binoculars and four- or five-inch telescopes

If you look two binocular fields north of Algol, the brightest star in Perseus and a variable star, you’ll come across the open star cluster Messier 34. Binoculars will not resolve any of the 90 member stars, but if you direct a small four-inch telescope its way, the stars will start to pop out.

9 IC 1396

Constellat­ion: Cepheus

Right Ascension: 21h 36m 23s Declinatio­n: +57° 19’ 59” Magnitude: +11.5

Minimum optical aid: CCD camera

In order to see IC 1396, a star-forming region that forms part of the Cepheus Bubble, you’ll need a CCD camera. Being incredibly faint, you would likely find it difficult to pick up this nebula and its darker regions, known as Bok globules, with binoculars or a telescope alone. Imaging IC 1396 will reveal a hot supergiant illuminati­ng its centre and yellow supergiant Mu Cephei at its edge.

10 Little Dumbbell Nebula (Messier 76)

Constellat­ion: Perseus

Right Ascension: 01h 42m 24s Declinatio­n: +54° 34’ 31” Magnitude: +10.1

Minimum optical aid: Six to eight-inch telescopes

Taking on an appearance similar to that of the Dumbbell Nebula, Messier 27, the pint-sized Little Dumbbell Nebula will require a telescope of at least six inches for comfortabl­e observing. Point your instrument to Phi Andromedae, a prominent blue star, then look slightly east and you will come across the nebula.

11 Capella (Alpha Aurigae)

Constellat­ion: Auriga

Right Ascension: 05h 16m 41s Declinatio­n: +45° 59’ 53” Magnitude: +0.08

Minimum optical aid: Naked eye

It’s not too difficult to find the rich, yellow-white star Capella, the sixth-brightest star in the sky, in the constellat­ion of Auriga (the Charioteer). Capella is actually a star system of four stars, which can easily be split into two stars. The yellowish tint of this star is much more apparent in a daytime sky with its contrast against the blue.

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