Shopping for a Telescope?

When you are an “astronomy guy”, around this time of year you get inquiries from friends looking to buy a telescope as a Christmas present. Often this is for a child or a grandchild, but sometimes the friend is shopping for him or herself. I must admit to skepticism when someone is willing to spend $1000 on a telescope for their four year old—just exactly who is this telescope for? :-)  But my role is not to judge, just to provide information and to make recommendations.

I want to make it clear that these recommendations are based on my personal experience from childhood until now. My first telescope (at age 10) was an inexpensive reflector from the Sears Roebuck catalog, and my current instrument is a top-of-the-line refractor. I see a lot more with my current scope than I did more than fifty years ago—I know a lot more, too—but I’m not sure I derive any more pleasure from its use. A different astronomy person would probably give you a different list. What that reflects is the wonderful range of options available today. When I built my own telescope in the late 1970s, it was better than anything I could have bought ready-made at the same price. In my opinion you are better served today buying that ready-made scope unless you are skilled in a number of areas beyond being able to use a tape measure, an electric drill and a screwdriver. That’s about all that was required for me in 1979!

Vendors

DO NOT, REPEAT, DO NOT buy anything from a store that does not specialize in telescopes. What you get there is cheap plastic junk. There are wonderful showrooms scattered around the country, but most people probably do not want to drive that far. The good news is that two vendors (Astronomics and Orion Telescopes) I have used extensively both have wide selections online and excellent customer service. These are certainly not the only vendors available! If you want to get an idea of what is out there, just pick up the latest issue of Sky & Telescope at your local newsstand. These are simply the ones with which I am most familiar.

Recommendations

(In increasing order of cost; costs are current as of November 10, 2013 and include any discounts current then.)

1.  A planisphere (star chart) ($10) A planisphere is a great way to start learning the sky. It really drives home the point that the time of day AND the time of year determine “what’s up”.
2.  Binoculars ($150) 7 x 50 binoculars are perfect  not only for astronomy, but also for nature watching and sports. The 7 means they are 7 power (everything is 7 times larger, i.e. it looks 7 times closer); the 50 means that each optical tube has an aperture of 50 mm. The 7 power is about as much as you can hand-hold without shaking, and the 50 mm aperture lets you see more stars since it lets in more light. People are amazed at how much you can see with binoculars. It’s a great way to start learning the sky.

When it comes to telescopes, here are the features to consider:

  • Reflector (mirror) versus refractor (lenses): The main advantage of a reflector is the lower cost for a given aperture (larger aperture means more light which equals more information which equals brighter and sharper images). A larger aperture lets you see deep sky objects (things beyond the solar system) which might be too dim for smaller scopes. Refractors have the advantage of closed optical tubes (you don’t have to protect the mirrors from dust and exposure), and they provide crisper, higher-contrast images. They can get expensive fast as apertures increase.
  • Aperture: Up to a point, the bigger the better. You pay more for bigger, of course. The light-gathering area goes up as the square of the aperture (the diameter of the light-gathering component); an 8-inch aperture gathers 4 times as much light as a 4-inch one. The point where this becomes a problem is when the scope is too big to be easily portable. A scope that is too much trouble to drag out is of no use to you, and certainly not to a kid.
  • Computerized go-to capability: This has gotten so (relatively) cheap, and makes things so much easier for a beginner (or someone more experienced), that I highly recommend it. But again, they don’t give it away for free.
  • What will you look at? Most kids, and most adults frankly, find the moon and the planets to be more impressive than distant galaxies, nebulae, or star clusters. The latter are just too subtle in most scopes of 6-inch aperture or less. It’s sort of like foods. Kids love sweets, and it takes some time to appreciate the fine points of more subtle flavors! So here are my picks, again in increasing order of cost:

3.  5.1-inch reflector ($260)
4.  6-inch computerized go-to reflector ($450) Personally, this one hits the sweet spot for me in terms of value for the money in a first telescope.
5.  4-inch go-to hybrid design ($450) This design combines mirrors AND lenses.
6.  8-inch Dobsonian reflector ($450) The Dobsonian design is simple to aim. But you do have to know what you’re aiming at, even when you can’t see it with the naked eye.
7.  4.7-inch refractor ($570)
8.  5-inch go-to hybrid design ($600) A bigger-aperture version of #5.
9.  8-inch go-to Dobsonian reflector ($930) The computerized version of #6.
10.  8-inch go-to hybrid design ($1000) A still-bigger version of #5; if I were going to spend $1000, this is what I would get. Good aperture, relatively compact and portable, and go-to capability.

Happy shopping! Feel free to email me with any questions you may have at sumerlin(at)lynchburg.edu.

Posted in Observatory and Telescopes

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