This Sky-Watcher 102mm (4") f/5 telescope is a two-element, air-spaced, fully multi-coated objective, achromatic refractor, which can give exciting "rich field" astronomical views. It can provide excellent vistas of star fields, clusters, nebulae, galaxies, planets, the Moon and (with correct filtering or by projection) the Sun. It is also a fine terrestrial telescope when mounted on an alt-azimuth mount or a photographic tripod.