Study the figure and answer the following questions :
Label the main parts of the telescope:

Hint: From the given figure, we understand that the equipment or instrument whose figure is given here corresponds to a telescope. Telescope is an instrument which is generally made up of lenses or curved mirrors, sometimes even both to see distant objects more clearly. It comprises different parts which are to be labelled here.

Complete step by step answer:
A Telescope is used to view distant objects such as stars, a planet or a distant tree, etc.,
In a reflecting telescope, the formation of images takes place by reflection. It consists of a concave mirror of large aperture and large focal length. A plane mirror is placed between a concave mirror and its focus, a small convex lens works as an eye-piece.

The concave mirror is located at the lower end of the telescope and has its front surface coated with an extremely thin film of aluminium. When light from the light source enters through the telescope, light converges by the concave mirror on the plane mirror at its focus and then, it drives the convex lens to the eye-piece. The plane mirror is placed at an angle respective to the direction of incoming light.

The ray diagram of reflecting telescope is as follows:


Note: It must be noted that the ray diagrams that we use during drawing an optical instrument must always denote the arrow to understand the directions of the ray of lights.The plane mirror in a telescope is mounted at an angle ${45^ \circ }$ with respect to the principal axis of the concave mirror used in the telescope. The optical telescope produces images which are at an angle ${180^ \circ }$ with respect to the real object.