The Orion ShortTube 80mm Rich-field Refractor

Abstract

Novice shoppers face a bewildering variety of choices in today’s telescope market. Some prospective buyers may opt for a fairly substantial Newtonian reflector on an altazimuth Dobsonian or equatorial mount, or perhaps a fork-mounted 125mm (5-inch) or 200mm (8-inch) Schmidt-Cassegrain catadioptric. However, the sheer bulk of such telescopes and time required to set them up and to allow for adequate athermalization (i.e., reaching thermal equilibrium with the ambient temperature) means that there will be many occasions when they are not used simply because of a lack of time or energy. The sexy 90mm (3.5-inch) and 125mm Maksutov-Cassegrains will catch a few eyes, but the limited fields of view produced by their high focal ratios and the less than ideal finderscopes sometimes supplied with them make it unlikely that newcomers to astronomy will have much success in using them to locate any but the easiest of celestial targets. (Those models equipped with robotic GOTO capability obviously do not suffer from this limitation.) Others may want to test the waters of amateur astronomy in a gentler fashion by buying a small first telescope, say a 60mm (2.4-inch) refractor or a 114mm (4.5-inch) Newtonian.