OPT is the Telescope Authority- and our wide selection of great Refractor Telescopes proves it! The word “refractor” means a telescope whose principal focusing element is a lens. A refractor telescope is a type of optical telescope which is also referred to as a refracting telescope. Its curved primary (or largest) lens gathers light, bends it, and sends it back to a focal point where it is further modified by the use of another set of lenses called the eyepiece. The curvature and size of the primary lens dictates the amount of distance needed to achieve the focal point.
OPT provides an extremely wide selection of reflecting telescopes that come in a number of varieties suited for a diverse range of applications. A reflector telescope refers to any telescope that uses one or more curved mirrors to reflect light and form an image. This results in images that are free of chromatic aberration, which is one of the main issues to plague models of telescope that do not utilize reflecting designs. One of the main benefits of the reflector design is that it enables a very wide diameter objective. This means that reflector telescopes are capable of being made much larger than comparable refractors, meaning that it is easier to make a reflector capable of gathering more light.
A Catadioptric Telescope is one that uses a combination of mirrors and lenses to increase the effective focal length of the telescope while allowing it to be folded into a more convenient and compact size. The use of a full-aperture correcting lens in these scopes virtually eliminates spherical aberration, chromatic aberration, and coma. The word catadioptric is derived by combining the term for an optical system that forms images by using mirrors (catoptric) with the one for a system that uses lenses (dioptric). The most popular catadioptric designs are the Schmidt-Cassegrain (SCT) and Maksutov-Cassegrain.