Reflecting type Telescope (Cassegrian telescope)
In such telescope, one objective lens is replaced by a concave parabolic mirror of large aperture, which is free from chromatic and spherical aberrations.
In normal adjustment, magnifying power
Advantages of Reflecting type telescope
- There is no chromatic aberration as the objective is a mirror.
- Spherical aberration is reduced using mirror objective in the form of a parabolic.
- The image is brighter compared to that in a refracting type telescope.
- Mirror requires grinding and polishing of only one side.
- High resolution is achieved by using a mirror of large aperture.
- A mirror weights much less than a lens of equivalent optical quality. Therefore, mechanical support of mirror is much less of a problem compared to the support required for the lens. Further mirror can be supported