By Duncan Lunan
To be an amateur astronomer on any level involves learning the constellations of the night sky. Once you know their patterns, you can immediately recognise the planets as they move against the stars. (You’ll also be able to spot artificial satellites and amaze your friends!) If you’re lucky enough to live in the country and have a dark sky, you have an immediate advantage; but as the ‘Dark Skies’ movement gains ground more and more towns and cities are switching to lighting systems which don’t fill the sky overhead with glare, so that even in town, if you can get out of the line of sight of surrounding lights, you can see the main stars which form the constellation figures, and find more with binoculars. Always remember that the sky was mapped and the motions of the planets were analysed before the telescope was invented: the best advice is to start with the naked eye and a map, then go on to binoculars.
Avoid small, cheap telescopes, especially for children: often they’re overpowered, and only frustrate the beginner into giving up. Magnifications of hundreds of times are hardly ever usable, even with large telescopes, and tend just to magnify the shimmer in the atmosphere. The higher the power, the smaller the field of view, and the smaller the aperture (the diameter of the tube), the less detail the telescope will be able to capture. Two things to remember are that unless the sight is correctly aligned, it will be hard to find your target in the telescope’s small field, and unless the telescope has a firm, steady mount, it will be hard to keep your target in view – especially because you have to follow it as the Earth turns. A 4-inch reflector is the basic beginner’s telescope, and it’s better to buy from a specialist supplier than from a high street store, where the staff are unlikely to be able to help if you encounter problems
Always remember the first rule of safety: NEVER LOOK THROUGH ANY OPTICAL INSTRUMENT AT THE SUN.
Magazines and Books
Good star maps for beginners can be found in most large bookstores, as can Planispheres, simple instruments which can be set for any day and hour in the year to show the stars then overhead. Similar maps and descriptive guides for each month are in “Philip’s 2021 Britain and Ireland Stargazing”, by the late Heather Couper and Nigel Henbest, in a series published annually; more detailed annual information is in “2021 Guide to the Night Sky”, by Storm Dunlop and Wil Tirion, published by Collins for the Royal Greenwich Observatory.
The BBC’s Sky at Night Magazine publishes maps for each month and is tailored for beginners. For more information Astronomy Now is the best magazine for UK observers, and both are available from large bookshops or can be ordered, while a quarterly subscription offers a substantial saving. For the USA perhaps the best general astronomical magazine is Sky & Telescope, produced by Sky Publishing Corp., of Cambridge, Mass., but now available in the UK. Astronomy is slightly more technical. For most purposes US magazines are usable in the UK, but the local times of events are different and often they don’t cover events which are visible here, but not in North America. Also, because we’re further north, we have a wider range of circumpolar constellations which are visible at all times of the year. For example, for much of the USA part of the Plough, or the Big Dipper as they call it, goes below the horizon late in the year, but we see it all year round.
There is a wide range of beginner’s books on astronomy, and the object is to find one which gives a guide to the constellation figures as well as general information. Probably you will find that after buying a few beginner’s books, seeking coverage of different topics, you’ll want to start buying more specialist ones on the Moon, the Sun, the planets, then on individual planets… Likewise for the stars, nebulae and galaxies.
Nowadays a great deal of information is available online or in the form of software such as Redshift or Starry Night. ‘Heavens-above.com’ is a particularly good website for current events: you can register with them and specify one or more locations, e.g. as well as Troon, where I lived until recently, I currently have the locations of my two brothers-in-law, in Sutherland and Wiltshire, and I added Trim in County Meath where I lived briefly, but you can specify anywhere in the world. When you log in, it will present a menu for the day’s events visible at your default location. If you click on ‘ISS’ for the International Space Station, you can opt for visible passes for up to ten days ahead, or for all passes including daytime ones. You can do the same for a range of other satellites and for Iridium flares, where the big solar panels of the Iridium communications satellites reflect light back to Earth. If you hover on an individual object in their new ‘Interactive Sky Chart’, which I used in the calculations for the recreated Sighthill stone circle in Glasgow, it will give you the co-ordinates of that object at that time, and you can set it for any time, then advance and retard the time in increments of a minute, correcting the changes by minutes of arc.
‘Universe Today’ is a good website for astronomy and space news, produced in Canada. Once you’re registered with them you’ll receive a weekly digest of the top news stories, plus access to a huge archive of earlier ones. ‘Space.com’ does constant updates on astronomy and space news, ‘Space Daily’ is another site which many people recommend, and ‘EarthSky’ covers the Earth sciences daily as well as astronomy and space, with a weekly roundup of top stories. NASA and the European Space Agency run similar news services, as well as features like ‘Astronomy Picture of the Day’, and it’s well worth signing up for news releases from the European Southern Observatory, to name but one. There’s a specialist website for solar-related events, ‘Space Weather’, and many more.
Duncan Lunan publishes a monthly column in The Orkney News on what to view in the Sky. The Sky Above You – March 2021