An observatory intends to compare the optical performance of reflecting and…
PHYSICS · Multi-part · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments
Problem
An observatory intends to compare the optical performance of reflecting and refracting telescopes.
(i) Draw a neat, labelled ray diagram of a Newtonian reflecting telescope in normal adjustment and, using geometrical relations, derive an expression for its angular magnification.
(ii) Show that the magnitude of the expression obtained in part (i) is identical to that for an astronomical refracting telescope used under the same viewing condition.
(iii) Using the expression derived, calculate the magnification for a reflecting telescope whose primary mirror has a focal length of 2.4m when it is used with an eyepiece of focal length 3.0cm.