The Milky Way, which dominated the skies of later summer, remains with us during the early part of the evening, stretching overhead – though it’s hardly visible for much of the UK population, who live in towns and suburbs. On the map above it runs from Cygnus at the top down to the right of Aquila. What we call the Summer Triangle is still high up, consisting of the thee bright stars Vega, Deneb and Altair. This area has several interesting fainter constellations which you can pick out with the naked eye in good skies or binoculars in poorer ones, so check out the guide for September to find out more.
From light-polluted areas, there are hardly any stars visible in the lower part of the sky, which is occupied by the constellations of Capricornus and Aquarius. Anyone who regards these as ‘their’ constellations on the basis of astrology is in for a disappointment as there are few bright stars. The skies were not cooperative in producing twelve nice bright pretty star groups evenly spaced around the track of the planets through the sky, as humans would have liked. Nor are there many objects of great interest in the area easily visible with binoculars or small telescopes.
But take a look at the Water Jar area of Aquarius, which is a very recognisable pattern of fairly faint stars, and which helps you to find your way around the rest of the constellation.
Also look at the stars Alpha and Beta Capricorni, which you can find by following the line of stars formed by Altair and its two companion stars southwards. You should be able to pick out with the naked eye that Alpha is a pair of stars. They are six minutes of arc apart, and the human eye should be able to distinguish two stars about 1 minute apart. Though they look similar, these two stars just happen to be in line of sight with each other. The easternmost one is around 100 light years away and the westernmost one is nearly 600 light years away. Look through a telescope and you’ll see that each of the two stars has another apparent companion, again probably not close enough to the main star to be part of a true double star system.
Beta Capricorni, too, is a double star as seen through a telescope, and in this case both stars are at about the same distance from us so they may well be linked by gravity, but taking hundreds of thousands of years to orbit each other.
Below Aquarius is a bright star that is often forgotten about from the UK, and also often mis-spelled. This is Fomalhaut, in the constellation of Piscis Austrinus, the Southern Fish. For some reason a lot of people call it Formalhaut so don’t make the same mistake. It is the most southerly first-magnitude star visible from the UK.
Coming into view farther east is the constellation of Pegasus, the Flying Horse. Its four main stars form a rough square – actually quite large in the sky, and the stars are only second magnitude, so don’t expect anything too easy. By counting the number of stars that you can see with the naked eye in the Square you can discover how dark your sky really is, in terms of the faintest magnitude visible. Our Young Stargazers page about Andromeda and Pegasus gives the details.
Back to September constellations Forward to November constellations