Write two advantages of a reflecting telescope over a refracting telescope.

Hint: The phenomenon of reflection is used in reflecting telescopes whereas refraction phenomenon is used in refracting telescopes. Mirrors are used in reflecting telescopes and lenses are used in refracting telescopes.

Complete step-by-step answer:
Advantages of reflecting telescope over refracting telescope”
Mirrors used in reflecting telescopes do not cause chromatic aberration while lenses used in refracting telescopes cause chromatic aberration.
The image formed in a reflecting telescope is brighter than the image formed in a refracting telescope.
Lenses used in large sized refracting telescopes are very heavy and bulky and difficult to manufacture whereas mirrors used in large sized reflecting telescopes can be made thin and light using different techniques.

Additional Information:
A telescope is an optical instrument that gathers light to form an image of a distant object. Telescopes of various sizes are available. Very large telescopes are used for astronomical observation to look into the deep sky. The aperture of the telescope decides the amount of light entering into the telescope. Magnification of a telescope is by the ratio of size of the image to the size of object.
In reflecting telescopes curved mirrors such as parabolic mirrors are used to focus a parallel beam of light on to a spot while in refracting telescopes the lens does this job.

Note: Both kinds of telescopes have some advantages and disadvantages. On a large scale mostly reflecting type telescopes are used because they are easy to mount and easy to repair. In reflecting telescopes light is reflected from the front side of the mirror, therefore there is no absorption and splitting of light.