What to do with Christmas telescopes

Almost every Christmas, I usually get a bit of correspondence like this: "We got [our son/daughter] a telescope for Christmas. Just a cheap made-in-China one, to see whether he/she is interested or not." As I wrote a reply about the perils and problems of such a purchase, I thought I'd share it with my friends and customers who may have the same issues or inquiries. There are many considerations about this subject and it's been covered often, but I hope my comments cover the essentials.

- Herb Johnson

PS: For more information about my astronomy activities, check my Astronomy home page.

I understand the desire to save money on a questionable interest. However the cheapest telescopes are SO cheap and hard to use, they are very discouraging. It's a good way to DISinterest someone. You'd do better to get a pair of used binoculars and a small book on looking at the night sky. And even with naked eyes, there is a lot to see if you know what you are looking at.

One point about binoculars: check them to make sure they are aligned. Look at a star or other small, remote stationary object, and blink one eye shut, then the other, alternating in rapid succession. If you see the star jump from eye to eye, the binoculars are not aligned. It's a common problem, don't fuss about small misalignment if you just want a cheap pair to start with, but large misalignments on cheap used binoculars is exactly the reason they ARE cheap, and they will be hard to use and strain your eyes.

A "guide to the sky" kind of book will give targets to look at and highlight constellations. The simple way to look at the sky is to just STAND out there and identify a few constellations which have neat large objects or bright stars. Planets are kinda hard to look at with a telescope because they are so small, but Jupiter and Saturn are big enough to see distinctly even by eye and they are pretty with any optic. The binoculars will help you find some objects, then you will know where to point the telescope! Meanwhile, in the early evening sky for about two hours after sunset, you can look for satellites. (The sun angle at that time makes them brightest.) Just look for slow moving objects by eye, or find a Web site that gives daily predictions for your location.

If you want to use that cheap telescope, do what you can to make the mount SOLID and stable. Most of them wriggle around too much. Also don't use a lot of magnification: it just amplifies the problems of the scope and any turbulence in the night sky. Start with low power.

DONT LOOK AT THE SUN WITH BINOCULARS OR TELESCOPES! There are safe ways to do so but not for the inexperienced. If that telescope has an eyepiece "solar filter", THROW IT AWAY it is not safe at all. A "moon filter" is OK for the moon, it's very bright and will dazzle your eyes through the telescope. Very experienced amateur astronomers can use proper equipment in the correct ways to observe the sun.

If your son/daughter gets more serious, members of a local astronomy club can help. A Web search will find them, or ask at the nearest science museum. You can often buy a better used scope from a member. In general a small reflecting telescope is a good start; I use a 6 inch (mirror diameter) f/10 (ratio of diameter to focal length) reflector myself. It's in a Sonotube (cardboard tube) and I used bits of plywood and pine wood in a simple mount. Such are easy to build, if you are looking for such projects, and the parts can be bought and/or fabricated. But even new Dobsonian telescopes (as they are called) are only a few hundred dollars for 6 to 8-inch apertures. Also, a number of science surplus stores (check the Web) sell 3-inch and 4-inch parabolic mirrors for reflectors for a few tens of dollars; some wood and cardboard and a few odd parts can make a decent little reflecting telescope from them. Plans can be found on the Web, in books from the library or bookstore, or from local amateur astronomers.

Herb Johnson
New Jersey, USA

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