Problem 5.47

At what magnification \(\Gamma\) of a telescope with a diameter of the objective \(D=6.0 \mathrm{~cm}\) is the illuminance of the image of an object on the retina not less than without the telescope? The pupil diameter is assumed to be equal to \(d_{0}=3.0 \mathrm{~mm} .\) The losses of light in the telescope are negligible.