peilitähystins

Peilitähystin, also known as a reflecting telescope, is an optical instrument that uses a mirror to gather and focus light. This is in contrast to refractors, which use lenses. The primary component of a peilitähystin is a concave primary mirror, which collects incoming light from celestial objects and directs it towards a focal point.

There are several common designs for peilitähystimet, distinguished by how the light is directed after being reflected by the primary mirror. The Newtonian design, one of the simplest, uses a small secondary flat mirror placed at an angle to redirect the light out of the side of the telescope tube to an eyepiece. The Cassegrain design uses a secondary convex mirror that reflects the light back through a hole in the center of the primary mirror to an eyepiece located at the rear of the telescope. Other variations exist, such as the Schmidt-Cassegrain, which incorporates a correcting lens to improve image quality.

Peilitähystimet are popular for astronomical observation due to several advantages. Mirrors are generally easier to manufacture in larger sizes than lenses, allowing for greater light-gathering capabilities. They also do not suffer from chromatic aberration, a phenomenon where different colors of light are focused at slightly different points, which can be an issue with refracting telescopes. This makes peilitähystimet well-suited for observing faint and distant objects in the night sky.