Buying and using a telescope - advice from Paul Fellows, of Cambridge Astronomical Association
Looking to get into astronomy but not sure where to start? We sought the advice of Paul Fellows, chairman of Cambridge Astronomical Association.
After starting with visual observation, it is worthwhile trying out binoculars, if you have some, before buying a telescope.
Paul notes: “Binoculars are great but there’s a dilemma about size. If they are too big and heavy, can you hold them still? If you are a certain age, you may not be able to. The more powerful, the more it magnifies the shake. You can end up spending a lot of money on binoculars with auto-stabilisation and by the time you’ve done that you could have bought a telescope.”
Buying a telescope can be a complicated business though, with many different types, sizes and mounts available.
“What I recommend is to try before you buy. I usually suggest people try a six or eight-inch Dobsonian reflector, which are exactly like our loan telescopes. They cost £200-£300 and most of the money is going on optics.”
Many modern telescopes have the ability to find and track celestial objects by tapping in some co-ordinates. This ‘GoTo’ function can remove some of the challenges of finding your chosen target.
Paul notes: “A lot of telescopes are sold on the basis of having GoTo facilities, and they are brilliant when they work, but they don’t work all the time. They work if you manage to set them up just perfectly, but unless you’re an expert you won’t get it set up perfectly. For a beginner it can be a false promise.”
For that reason, getting a solid understanding of the night sky is a good way to start.
“The old ways are the best for learning,” says Paul. “If you learn where all the constellations are and are able to find things, it will hold you in good stead, even if you then have a GoTo that takes away some of the burden.”
It is a hobby, he acknowledges, best approached with “patience and optimism”.
...on what to look for first through your telescope
“I tell everyone to look at the moon first, a few times, then move on to the planets,” he says. “Anyone can find the moon. But, when you’re first starting, the planets can be quite difficult to find.
“A lot of people who buy a GoTo and complicated equatorial mount with all the gizmos find they can’t get it to work, they can’t get it aligned properly, they can’t get it in focus and the GoTo doesn’t help them, but with the moon, it’s so bright, you can’t go wrong.”
Once you’ve studied the moon and explored the planets, you can move on to other targets.
“I point people at some of the brighter star clusters, nebulae and galaxies, which will vary depending on the season.”
Taking photographs of the night sky is now very popular – but it can get very complicated, very quickly.
The Cambridge Astronomical Assocation’s 10-week Introduction to Astronomy course includes sessions that cover some of the ways to get started.
“We do one lecture on just imaging the sky with a camera. I’m old enough to remember doing it with real film and developing it myself. That was painful! But modern digital cameras make it so easy,” he says.
Images of the moon, of the Milky Way stretching across the sky and of constellations are possible with a camera alone, if you get your settings right.
Bear in mind that as the Earth is moving, long exposures will lead to ‘star trails’ as the stars move across the sky – which can lead to brilliant photographs too.
Taking photographs of the planets, other galaxies and deep sky objects requires the use of a telescope connected either to a dedicated astrophotography camera that fits in an eyepiece, a normal DSLR connected via a T-mount adapter, or a webcam-style camera.
Deep sky astrophotography is another of the sessions covered in the CAA course, which costs £10, or £2 per session.
With today’s equipment, it is possible to capture great images, explains Paul.
“I’ve got some of Patrick Moore’s books from the 1960s, with images taken by a 200in telescope in California, and the quality I get from my back yard is much better,” he says. “I get some pretty stunning results, but it took me quite a few years to master. You need different methodologies or cameras for the moon, the planets or other objects.
“I’ve done the grand tour and photographed all of the planets, then moved on to some of the bigger deep sky objects using a hydrogen alpha filter. It’s a very narrow waveband filter, which just takes one wavelength from hydrogen gas. The advantage is it cuts through the light pollution.”
Read our full interview with Paul Fellows on how he got into astronomy, and find out more about the public open evenings at the Institute of Astronomy, and events for young stargazers.