Well, with Winter out of the way and balmy nights ahead our thoughts once again turn to sky watching. Everything in astronomy involves peering through this long tube we call the telescope. So, what exactly is a telescope and what do they do?
Well, for one thing, telescopes don’t magnify anything, they just gather light. It’s true! The real magnification comes from the different lenses, or eyepieces you pop in the scope.
Think of a telescope then as a ‘light bucket’ – the bigger the bucket, the more photons a telescope can collect. The lens or mirror in your telescope collects the light from the Moon, a planet or distant star and sends it through the eyepiece to your eye where it’s magnified.
Astronomy is one of those hobbies where bigger is better but be careful, you only get what you pay for. Telescopes today are made to a price, not a quality, and the trade-off is usually in the eyepieces. Cheap toy telescopes found in department stores are to be avoided.
In Australia, any telescope under $250 is considered junk so beware. A good pair of binoculars on a tripod can be better than a cheap telescope that wobbles in a light breeze and won’t focus properly.If your telescope shows everything as blurry or distorted, it’s probably a lousy eyepiece that came in the box. Simply replacing it can breathe new life into a telescope that could have been relegated to the junk heap. Look for the letters ‘H’ or ‘K’ on the barrel. If you find that stamped there replace them with better quality units like Plossls.
By the way, Galileo didn’t invent the telescope. History got that one wrong. Hans Lippershey, a Dutch spectacle maker is usually acknowledged for the earliest recorded design for an optical telescope in 1608. Galileo was, however, the first one to turn it into a commercial proposition.
Hey, I almost forgot. When buying a telescope decide if you just want to observe the heavens or take it outside in the daytime as well. Some telescopes invert the image – that’s right, they turn everything upside down! Reflecting telescopes, popular with a lot of amateur astronomers, will do this but a refractor won’t. So, if you intend packing the scope for a day out whale watching followed by a night session in the backyard, go for the reflector OK.
Observe away from buildings, pavement or large objects that absorb heat by day and release it at night. The best locations are open, grass covered areas. For a similar reason, observing through an open window is also a bad idea. Allow your eyes to become dark adapted before trying to observe faint deep sky objects. This takes time, typically 15 minutes under truly dark conditions. Unfortunately, it only takes seconds to ruin your dark adapted eyes by looking into a bright light again.
One last thing, control the magnification when using your telescope. Too much power is the single biggest mistake beginners make with a telescope. Excessive magnification yields a fuzzy, very dark image. OK, open the door. Mars and Saturn begin the month still close together in the west, with the Moon just to the right of Mars. In the early evening, the Southern Cross can be seen in the south west, tipped over on its side, with the two ‘pointers’ almost vertical above it. The Milky Way spans the sky overhead, looking splendid as it stretches almost north south tonight.
Scoping The Spring Skies
You know, a telescope is really a subtle space ship of the mind. Its range is limited only by your willingness to be patient. Learn how to use it to its best advantage and learn how to really see what it is showing you. Be aware though that the views won’t look like the full colour spreads in magazines and books. Only instruments like Hubble can do that.
The Moon will be dazzlingly bright and sharp with a lifetime of detail to explore. The planets will look very small, even with high power, but if you’re patient you’ll be surprised how much colour and subtle detail will be revealed, especially during brief moments when our atmosphere is steady.
All of your observing with the unaided eye, binoculars or a telescope will be easier and richer with the help of good over the counter sky software like Starry Night. Here’s a tip – if you go to www.stellarium.org you can download a program almost as good. I use it all the time. It’s easy to use, and free to download.
Take your time and really observe an object. This technique probably cannot be overstated. Spending even 2-3 minutes studying what’s in your field of view will reveal vastly more detail than simply glancing at an object then hurrying on to the next. A quick glance at Saturn for instance shows it rings, a long look reveals divisions in those rings, cloud bands, subtle colorations, and moons. No technique in astronomy will show you more than spending time examining an object in detail with your own eyes.
Let’s start with one of the easiest to find yet most rewarding objects when visible, the Moon. Its rugged craters, high mountains, and vast ‘seas’ offer some of the finest details to be found in any astronomical target. It changes every night as the terminator, the line between sunset and shadow, progresses over the surface, revealing new details.
At first, the lunar landscape will look quite confusing, but keep in mind that lunar north has fewer craters than lunar south. As you study the Moon from month to month craters will become more familiar to you. Notice those huge flat grey areas? They’re called ‘seas’ after Galileo who first spotted them through his newly invented telescope. He thought they were oceans but they’re just cold grey flat lava beds, some hundreds of kilometres across!
So, where should you set up? Footpaths and rooftops absorb heat during the day and radiate it back off during the night. The resulting turbulent air can distort the image through your telescope. So for best results, set up your telescope on dirt or grass, which absorb much less heat, and avoid aiming directly over nearby buildings.
The best time to view an object is when it is high in the sky. There’s less pollution and less sky glow, so the view will be clearer.
Light pollution decreases late at night, as downtown businesses close and households turn off outdoor lights. Try stargazing near midnight or during the ‘wee hours’ of the morning when possible. You know, astronomy is now your own personal voyage of discovery into the depths of the universe and your telescope is your spacecraft. The glory of it all is that we can do it from our own backyard. Enjoy. For a FREE 323 page e-book “The Complete Idiots Guide To Astronomy” subscribe to Dave’s weekly newsletter www.davidreneke.com