Binoculars and telescopes and other astronomy equipment and accessories are the meat and potatoes of amateur astronomy. A good pair of binoculars is what introduced me to the joys of stargazing many moons ago and only after a couple of years of scanning the skies did I graduate to a telescope. That was one of those 60mm department store telescopes we’re all warned about, but my parents didn’t know any better, and for a 12-year-old, it opened up the universe.
telescopes
While cheap (in every sense of the word) telescopes can still be found, small but very affordable telescopes have been introduced in recent years from manufacturers such as Meade and Celestron, and despite their small size, these telescopes have optics excellent. beat the cheap optics in my old 60mm scope from so long ago.
Many of these small telescopes now come with GOTO functions that allow you to select an object to view from a connected phone and the telescope will automatically pan to that function in the sky. What the ads tend to forget to mention is that to use this feature, the telescope must be properly set up and aligned beforehand. Unfortunately, many scopes sit gathering dust in corners and cupboards because their owners didn’t know how to use them. It’s not their fault – better and simpler instructions should be provided with the telescopes. But for those who can work with such an instrument, there are a large number of celestial objects available to view that would be quite difficult to find otherwise.
Some veterans of astronomy societies have openly embraced the new technology, others have criticized its introduction as it prevents newcomers from learning to move through the heavens using a technique called star hopping. Somehow they see that there must be a bit of pain in finding an object before you can have the pleasure of seeing it. I guess it’s a bit like the difference between taking the bus to Machu Pichu or taking a five hour hike up the mountain to see it. What would you choose? If walking is your cup of tea then star jumping is for you.
Personally, I think the introduction of GOTO mounts has been a very positive development and has made the hidden beauty of the night sky accessible to many more people. If you’ve purchased a small telescope with an integrated GOTO mount, but aren’t sure how to use it or the best objects to view, go to your local astronomy club or society and ask them for help. They will be very willing to lend a helping hand.
On the other hand, if you want to develop an understanding of the night sky, then a simple Dobsonian telescope is a good place to start. These 6-inch and larger reflector telescopes come on simple mounts that allow you to rotate the telescope left and right and up and down so you can easily aim it anywhere in the sky.
Amateur astronomer Kevin Berwick’s article Choosing a Telescope discusses the different types of telescopes available and provides sage advice on which one is best suited for your needs.
eyepieces
You should have a selection of eyepieces to use with your telescope to allow for close-up views or wide-field views. Planets require small-diameter eyepieces to see surface detail, while larger subjects, such as the Pleiades and other large star clusters, require wide-field views. Almost any eyepiece can be used to get a good view of the Moon or close-up views.
Eyepieces range from approximately 3mm to 40mm (ie the glass in them, not the diameter of the eyepiece itself) and come in three settings: 0.965″, 1.25″, and 2″ (for higher-end telescopes). The 0.965″ setting is rarely used these days, but older telescopes used eyepieces this size. There are also different types of eyepiece: Plossl, Erfle, Kellner, Orthoscopic, wide angle, etc. The magnification an eyepiece provides depends on the focal length of your telescope: divide the focal length of the telescope by the size of the eyepiece to get the magnification. A typical refractor (uses lenses instead of a mirror) has a focal length of about 900mm. A 26mm eyepiece would provide 34x magnification with this scope. Used with a telescope with a focal length of 2000mm, the magnification is 77x.
There is another feature of eyepieces called Field of View. Basically, this is how big an area of the sky looks through the eyepiece. The larger the field of view, the more you can see. The amount of sky that is seen depends on the diameter of the eyepiece and the focal length of the telescope. Wide angle eyepieces (82 degree field of view, for example) tend to be quite expensive. Average eyepieces, like Plossls, have a field of view of about 50 degrees. Wide angle eyepieces can almost give you the feeling of “being out there”.
Binoculars
While this discussion has mostly focused on telescopes, binoculars also have a role to play in astronomy. A quality pair of binoculars costs less than a telescope and is a good entry point for someone new to the sky. They don’t offer the same magnification as a telescope (but magnification isn’t everything), but they do have a much wider field of view that makes it easier to navigate the sky. Due to this wider field of view, you can also see the ‘big’ picture. And, because you’re using both eyes, there’s less eye strain. You can get binocular scopes for telescopes and those who use them (even though they cost a few hundred bucks and you need two of each eyepiece) swear by them (rather than!). A typical set of binoculars will be 10×50 (50mm wide front lenses, with 10x magnification). There are more powerful models available – 20x60s are available starting at $150 and you can get 20x80s for as low as $215. These binoculars are quite heavy and you can easily tire yourself pointing them up at the sky for any length of time. Also, due to its higher magnification, any shaking in your hands will also be magnified and the stars will move rapidly across the view. For long-term viewing, it is recommended that you obtain a tripod and a binocular tripod adapter that allows you to mount the binoculars securely.
Binoculars are also excellent for observing large-scale celestial objects, such as comets. Looking at the Moon through 20x binoculars gets it close enough to see the topography, but you’ll also see it in three dimensions, something that’s missing when looking through the eyepiece in a telescope. You can get out a pair of binoculars much faster than setting up a telescope, so if you have a very changeable climate where you live, they might be a better option for skygazing. Of course, you can put a pair of binoculars in your luggage very easily and view the sky from your vacation destination with ease.