The Anatomy of a ShortTube 80

Abstract

In the last chapter, the reader was given a flavor of just how well the little ShortTube 80 achromatic telescope could serve as a very satisfying, portable astronomical portal. However, this was but the tip of a proverbial iceberg of the impressive versatility the instrument is really capable of. Doubtless, the secret of the ShortTube 80’s success is its simplicity and affordability. At its heart lies a doublet objective composed of traditional crown and flint elements. For optimal performance, the elements are not in contact but are separated by a tiny air space created by placing three small foil spacers between the crown and flint glasses. With an aperture of 80 mm (3.1 inches) and focal length of just 400 mm, the ShortTube 80 is capable of delivering very crisp, high-contrast views of a whole suite of deep sky objects. Its short focal length allows it to render very wide field views that are much more difficult to achieve in virtually any other instrument currently on the market.