Question

The above ray diagram is to show image formation by a reflecting telescope. Reflecting telescope revolutionized our way of looking into the sky. Reflecting telescopes employ large mirrors to gather and focus light rather than relying solely on lenses as we do in the refracting telescopes. These telescopes utilize precisely shaped and polished mirrors to capture incoming light and reflect it to a focal point, where the telescope forms an image for observation.

(a) What kind of image of a star is seen by the observer in the eye-piece

(b) What kind of mirror is used in this reflecting telescope?

(c) Explain with the reason, what kind of optical device (type of lens or mirror) is used at the eye-piece.

OR

(c) What is the role of plane mirror in mage formation by this telescope?

Answer 1

(a) The image of the star seen by the observer at the eyepiece is a real image, as the final image is formed by the converging lens at the eyepiece.

(b) The curved mirror used in this reflecting telescope is a concave mirror, which gathers and focuses the incoming parallel rays of light from the distant star.

(c) A converging lens (convex lens) is used at the eyepiece to collect the rays reflected from the plane mirror and to allow the observer to view a real and erect image of the star.

OR

(c) The plane mirror in the telescope laterally inverts the image formed by the curved mirror, and its position helps to redirect the rays towards the eyepiece, enabling comfortable viewing of the image.