In September, Jupiter is the most prominent planet in the night sky. Look towards the South just after sunset, and Jupiter is low in the sky. On 9 of September, the Moon can be seen just below Jupiter, acting as a convenient guide.
At this time of year, the Earth is on the side of the Sun which allows us to look up at constellations such as Hercules, Cygnus and Lyra.
In Cygnus, the star that makes up the head of the swan is called Alberio, a colourful double star in a small telescope.
In Lyra, another nebulae is visible through a small telescope – the ring nebula. Looking like a ring of smoke, it lies 1500 light years away. At the centre is a very hot white dwarf star emitting intense ultraviolet radiation, causing the ring to glow.
Directly overhead in the evening is a triangle of bright stars – Vega, Altair & Deneb. They are known as the summer triangle. Even though the trio appear to be of similar brightness to each other, in reality Deneb is much brighter. It is one of the brightest stars we know of, 250,000 times brighter than the Sun. It only looks as bright as Vega & Altair because it is 100 times further away. If it was as close as either, it would be as bright as the Moon!
Visible towards the North-West this month is the great globular cluster in the constellation Hercules. Through even a small telescope the sight is stunning. This cluster contains several hundred thousand stars, and lives on the very outskirts of our own Milky-way galaxy.
Look towards the North, and you can find the pattern of stars called the Plough (the tail and body of the constellation of the Great Bear, Ursa Major). The handle of the Plough points towards Arcturus, which can be remembered by the ditty “Follow the arc to Arcturus!”. Arcturus is a bright red-giant star, 16 times wider than our own Sun, and over 100 times brighter.
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