Aperture of astronomical telescope is large -  

What is meant by the resolving power of a telescope? State any one method of increasing the resolving power of an astronomical telescope.

An astronomical telescope has an objective of focal length $200 \mathrm{cm}$ and an eye-piece of focal length $10 \mathrm{cm}$. An observer adjusts the distance of the eyepiece from the objective to obtain the image of the sun on a screen $40 \mathrm{cm}$ behind the eye-piece. The diameter of the sun’s image is $6.0 \mathrm{cm}$. Find the diameter of the sun. The average earth-sun distance is $1.5\times {10}^{11}\mathrm{m}$.

Draw a labelled ray diagram of an image formed by a refracting telescope with final image formed at infinity Derive an expression for its magnifying power with the final image at infinity.

A telescope objective has a focal length $1.00 \mathrm{m}$. When the final image is formed at the least distance of distinct vision ($25 \mathrm{cm}$), the distance between the lenses is $1.05 \mathrm{m}$. Calculate the focal length of the eyepiece and the magnifying power of the telescope.