THE end of this month will see the clocks go back and the start of the long dark evenings we amateur astronomers look forward to.

There have been some beautifully clear evenings recently, to the extent that I spotted a very rare sight indeed. Not a comet or the zodiacal light, but my daughter standing in the garden beside me looking at the night sky. Conditions must have been particularly mild otherwise this 'hothouse flower’ would not have set foot outside after sunset!

Then I was asked the question most of us ponder at one point or another, 'How many stars can we actually see up there?’ The answer is perhaps a little surprising (and was also a little disappointing to my daughter). Under ideal dark sky conditions, someone with good eyesight should be able to spot just over 2,000 stars with the naked eye. The 'Bright Star catalogue’ first compiled in 1908 lists 9,096 stars at or above the magnitude (brightness) visible to the human eye and scattered across the entire sky, both north and south of the equator.

In our case we have to restrict ourselves to the stars visible from the Northern Hemisphere, but remember too that at any particular time only half of the Earth (the half facing away from the Sun of course) is actually in darkness, so we have to reduce this number by half again. Throw in the effect of the curvature of the Earth itself and we have to reduce the number a little further which brings us to around the 2,000 mark.

Viewing location has a huge impact on this number, with the glow from the likes of street and security lights in towns and cities reducing the figure to anywhere from 200 down to 20! On a local level we should appreciate how very fortunate to have easy access to a reasonably dark sky and we should strive to maintain it. I was able to stand on Tweed Green in the middle of Peebles recently and clearly view the hazy path of the Milky Way directly overhead, something many city dwellers have never seen due to light pollution.

But what about going the other way? How many more stars can you see with, say, a pair of binoculars? Well, with a very modest pair the number increases from 2,000 to over 30,000, whilst a small, reasonably priced amateur telescope moves it up to over 3.5 million! This number was much more acceptable to my daughter.

Of course, you can’t see this number of stars all at the same time when using binoculars or a telescope, you’re just looking at a tiny fraction of the sky, but with these tools for gathering more light and magnifying the sky you can see much more than just stars. Star clusters, double stars, glowing nebulae, the remnants of dead stars and vastly distant galaxies all become visible and these objects provide a virtually endless treasure trove for amateur astronomers to observe.

Tweeddale Astronomical Society will hold its next meeting at The Osprey Centre, Kailzie, on Tuesday, October 21, starting at 7.30pm. Do join us if you have an interest in space or the night sky. No telescope is required! You can currently follow the activities of the Society on its Facebook page, A website for the Society is currently under construction, so more details on that next time.

Until next month, look up and 'Clear Skies!’ Dr. Tom Johnston Tweeddale Astronomical Society