Sky-Watcher Startravel-80T, 80mm (3.1"") f/400 Short-Tube Achromatic Refractor Optical Tube Assembly. The compact Sky-Watcher Startravel series are two-element, air-spaced, multi-coated objective, achromatic refractors, and are well proven performers forRich-Field' views of star fields, clusters, nebulae, bright galaxies, planets, the Moon and the Sun (with correct safety filtering!), as well as giving excellent terrestrial views. These wide-field short-tube telescopes are also highly portable. They also are popular for use as guide scopes on larger telescopes. All models excel as fixed aperture lenses for both Astrophotography and terrestrial photography. Their ""fast"" focal ratios make them useful for capturing lunar and solar eclipses as well as nature photographs. Tube material: Aluminium. Please note, this is an Optical Tube Assembly only, mount and tripod are available separately.