Question

Explain image formation in a reflecting telescope with the help of a ray diagram. Compare its qualities with a refracting telescope.

Hint:

Reflecting telescopes do not suffer from chromatic aberrations, making them ideal for astronomical observations, especially for large telescopes.

Answer 1

In a reflecting telescope, the image is formed using a concave mirror. When parallel rays of light from a distant object fall on the mirror, they converge at the focal point to form the image. The ray diagram of the image formation is as follows: \includegraphics[]{reflrcting tele.PNG} Comparison with a refracting telescope: \begin{itemize} \item Optical Medium: A reflecting telescope uses a mirror, while a refracting telescope uses lenses. \item Aberrations: Reflecting telescopes do not suffer from chromatic aberration, whereas refracting telescopes do. \item Size: Reflecting telescopes are generally more compact than refracting ones for the same focal length and aperture size. \item Cost: Mirrors are easier and cheaper to produce than large lenses, making reflecting telescopes more cost-effective. \end{itemize}