A spotting scope is essentially a highly portable telescope mainly designed for observing terrestrial subjects, but suitable for a wide range of applications including photography and astronomy. The light gathering power of a spotting scope is determined by the width of the objective lens, and its magnifying power varies between 20-60X depending on the model. Spotting scopes come in two essential designs: the "straight-through" (the eyepiece is on the same axis as the body of the scope) and "angled" (the eyepiece is at an angle of about 45 degrees to the body of the scope). Straight-through design spotting scopes are easier to use when mounted on a taller tripod, while angled spotting scope models are more comfortable for tall people and more easily shared by people of different heights.
Ultimately portable, rugged and well suited to travel, the spotting telescope is designed either as a refractor of a cassegrain. Some models come with a fixed eyepiece, a variable zoom eyepiece or interchangeable eyepieces. Many models include a table top tripod and all are compatible with a variety of mounts. Like their larger cousins, the telescope, spotting scopes also have a magnification "limit". 20X to 30X yields an excellent field of view and a bright image. While higher magnifications up to 60X are possible, the restricted field of view requires a steady mount. Well suited for bird watching, wildlife studies and photography, the tough, durable and maintenance-free spotting scope also makes an excellent beginner telescope. A spotting scope is the perfect companion for the traveling astronomer to tuck into luggage or carry-on.