Fall 1999 MIRA Quarterly Newsletter: Looking Up

Fall 1999

Looking Up
How to Buy Your Child a Telescope
with Dr. Arthur Babcock, President, ASCC

As no reader of this publication can doubt, and as telescope makers’ advertisements in the amateur astronomy magazines confirm, the urge to buy a telescope for one’s child or grandchild is a universal impulse. Here are a few tips that will virtually guarantee that the acquisition of such an instrument will lead in short order to a brilliant scientific career and the advancement of mankind. To ignore them is to risk a life of sorrow for both the recipient and the misguided donor.

The best authorities are unanimous in their condemnation of the so-called "department-store telescope." These are generally small refractors with an aperture (lens diameter) of 50mm to 60mm. According to the box advertising, the telescope will magnify objects hundreds of times (550 power!) and enable to user to see craters on the Moon, the rings of Saturn and galaxies.

While none of these claims is exactly false, such a marketing strategy produces rather unsatisfactory telescopes. The problem is that any magnification over about 100x on an instrument this size is wasted: the 550x image will be so dark and fuzzy as to be unrecognizable, and at that magnification, the telescope’s field of view is so tiny that finding anything at all is a matter of pure chance. Moreover, the flimsy telescope mounting will shake badly in the slightest breeze and go completely crazy when one touches the focusing knob.

In fact, magnification is usually not mentioned prominently in the marketing of quality astronomical telescopes (scopes for nature study and target shooting are a different matter). This is because eyepieces are interchangeable, yielding a range of magnifications, and because magnification is only one of the important functions of an astronomical telescope. In acquiring a small instrument for a child, it is far more important to look for light-gathering power (i.e., the diameter of the lens or mirror) and a smooth, solid mount that will allow the telescope to be pointed accurately and to withstand light wind without shaking itself to pieces. The telescope should have a low-power eyepiece magnifying only 25 or 30 times, and perhaps a high-power eyepiece (say, 80x-100x) as well.

But will a modest, low-powered instrument such as this deliver "craters on the Moon, the rings of Saturn, and galaxies?" Yes, indeed, and much more readily than the high-powered monster.

Where to turn? I will mention a couple of local sources. The Nature Company in Carmel (624-1334) carries telescopes suitable for beginners, and Orion Telescopes and Binoculars, headquartered in Watsonville (catalog orders only), has retail outlets in Cupertino and San Francisco. The Orion catalog contains quite a bit of information designed to educate consumers about the products they carry. The catalog is free; call (800) 447-1001. Other good retailers may be found in Sky and Telescope and Astronomy magazines.