An amateur astronomer builds a Newtonian reflecting telescope using a primary mirror…
PHYSICS · Multi-part · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments
Problem
An amateur astronomer builds a Newtonian reflecting telescope using a primary mirror of focal length 1.20m. In the first trial an eyepiece of focal length 20mm is used in normal adjustment.
(i) Calculate the angular magnification obtained in the first trial.
(ii) The astronomer then replaces the eyepiece with another of focal length 10mm. Determine the new magnification.
(iii) For the first trial, estimate the separation between the vertex of the primary mirror and the eyepiece along the telescope tube, assuming that the flat secondary mirror only changes the direction and not the location of the primary focus.