Learn about astronomy with Robin Bellerby

September sees good opportunities for those interested in stargazing – we are all praying for fine, cloudless nights.

The Autumnal Equinox this year falls on September 23 and this is when daylight and night-time hours are equal. From then onwards the nights start getting longer, it gets dark earlier and earlier (until at the end of October the clocks go back to GMT and we meet darkness an hour earlier in the evenings) and so observers are given more time in darkness and more social hours instead of having to wait till 1 or 2 AM as we do in summer.

The nearest full moon to the Autumnal Equinox we call the Harvest Moon, and this year because it is closest to the Earth in its orbit round us it will appear bigger than usual. This month also sees a total eclipse of the moon (which always occurs when the moon is full) – more about that a little later.

Talking to people in this area about stargazing, many complain that people with no knowledge or experience go out and look at the night sky the total number of objects visible is quite baffling. In the rest of the UK if you can find a reasonably dark place you can count on seeing something like 2000 objects in the sky. In the Galloway Forest Dark Sky Park, University of Glasgow staff have “counted “over 7000 objects. It is no wonder that people take one look at the sky, shake their heads and walk away. However, with a little basic information it is possible to break down what is up there into parts which are more easily understood.

On the morning of Saturday, 26 September at 10:30 AM, a short talk, “What’s Up, Doc?”, will be given by Dr Robin Bellerby (Fellow Royal Astronomical Society), in the ground floor lecture room of the MacMillan Hall, Newton Stewart, for absolute beginners – . It will describe just what you can expect to see in the sky, what the objects are, and how to tell them apart. This talk is being given in support of Alzheimer Scotland and admission is by donation, suggested minimum £5.

Later on the same evening there is another event taking part, part of which will see Professor Martin Hendry, Head of School of Physics and Astronomy, Professor of Gravitational Astrophysics and Cosmology (University of Glasgow), deliver a talk “More than Meets the Eye” (visible and invisible objects in the Cosmos) at 8 pm as part of the Sanctuary 2015 event near Murray’s Monument on the A712 (advertised separately, http://sanctuary2015.org/talks-events/). He will follow this by taking those interested on a short walk in the dark forest, pointing out what objects are visible in the sky.

Finally, what can we expect to see at the full moon on the night of 27th-28th September? (In the early hours of 28th). It is a time when the Sun is on one side of the Earth and the moon directly opposite. The moon enters the shadow of the earth and an eclipse occurs. We see the moon in sunlight reflected back to us from its surface, and you might imagine that the moon would disappear completely at this time, but because the earth has an atmosphere, some light bends round the earth and falls on the moon. The red wavelengths of light (the longer light waves) bend more than the others and so the moon reflects back to us some of this light and the moon can appear red or sometimes orange. (This is a similar effect to the bright red/orange colour we see just before the sun rises over the horizon in the morning or just as it is setting in the evening). This event is rather dramatically called a Red Moon, which the Russians love to call it, or a Super Blood Moon as our friends on the other side of the Atlantic prefer to call it. Whatever its name, it is a good opportunity for photographers to capture a series of images from the first ‘bite’ out of the moon, to full eclipse and then partial eclipse as the cosmic dance continues. Unlike an eclipse of the sun an eclipse of the moon is spread out over a couple of hours so there is plenty of time to observe and manipulate cameras etc.