Ancient stars

Ken Kennedy of Dundee Astronomical Society tells us what to expect to see in the sky next month. “September heralds the arrival of interesting winter constellations,” he says. “The Summer Triangle of Vega, Deneb and Altair is still high in the south-west but the great flying horse, Pegasus, is edging towards a southerly position.

“The four stars forming the body of Pegasus are prominent in the southeast. Remembering that the horse represented by the stars is inverted, the neck and head of the horse extend downwards with the tip of the nose, marked by the star Enif, almost due south at 10pm. Binoculars out again and find Enif, then move about five degrees west and you should come upon a rather fuzzy star.

“This is the globular star cluster Messier 15 which is a compact cluster of ancient stars at a distance of 33,600 light years. Telescopes with an aperture of six inches will start to show individual stars of the cluster. M15 is one of the most densely packed globular clusters.

“Although Jupiter and Saturn are at a low elevation, this is a good time to have a look at them with binoculars or a small telescope. If you hold binoculars steady, you should be able to see the four largest moons of Jupiter, first seen by Galileo in 1610. These moons will be in a line but will change position each night as they orbit the planet. If you have a small telescope you may also see a couple of dark bands on the planet’s surface. These are bands of cloud drawn out by Jupiter’s rapid rotation.

“Looking at Saturn with binoculars you may get the impression that the planet is not quite circular but you are unlikely to be able to make out the actual rings unless you have very powerful binoculars. A small telescope will reveal the rings of Saturn, as they are quite widely open at this point in its orbit.

“Mars is becoming closer during