Autumn is starting to grip tight and even the most casual sky watcher can see the constellations are changing rapidly each night, writes astronomer Neil Norman, of Hadleigh.

East Anglian Daily Times: Astronomer, Neil Norman Picture: SARAH LUCY BROWNAstronomer, Neil Norman Picture: SARAH LUCY BROWN (Image: Archant)

September is all about the planets for the naked eye observer looking to the skies over Suffolk.

Jupiter and Saturn are visible all night in the south and are appearing to draw closer as they head towards a December close conjunction of historic proportions.

The brighter of the two is Jupiter and even modest binoculars will show you the four principle moons, Io, Callisto, Ganymede and Europa. Each one of these moons are equal in size or more than the planet Mercury and over the course of an evening you can observe them to move as they orbit their giant host.

From 8.30pm each night the glowing red orb of Mars appears in the eastern sky. The planet cannot be missed as it continues to brighten ahead of its opposition in October when it will be very bright. Binoculars reveal surprisingly nothing of surface details but anyone with a 6 inch telescope will be able to pick out markings on the surface as well as the polar ice caps.

East Anglian Daily Times: Astronomer, Neil Norman Picture: SARAH LUCY BROWNAstronomer, Neil Norman Picture: SARAH LUCY BROWN (Image: Archant)

The international space station will be visible from mid-month onwards in the evening skies.

Have you ever wondered why stars are different colours?

The colour of a star is a guide to the temperature of the surface; for example, orson is yellow and has a surface temperature of some 5,000C, red stars are cooler and also older with surface temperatures of just a couple of thousand degrees. On the other hand, the hottest stars in the sky are the blue and bluish-white ones, with temperatures of over 20,000C.

These stars are young and burn through their fuel supply quickly and, as I call them, do a James Dean - live fast, die young.

And finally, we currently have the brightest galaxy visible to us in the sky this month - the Andromeda galaxy.

Using the planet Mars as a guide you will see directly above it a large constellation that looks like a square, this is the square of Pegasus and just to the side of this you will notice an orange star, sweep up with binoculars slowly and you will see a misty patch, that is the Andromeda galaxy, a galaxy that will one day in many, many millions of years collide with our Milky Way galaxy.

The most astonishing thing about this galaxy is that it lies some 2 million light years away, by far the brightest and most distant object that can (under perfect sky conditions) be seen with the naked eye.