Question

The refracting telescope at the Yerkes Observatory has a 1.00-m diameter objective lens of focal length 20.0 m. Assume it is used with an eyepiece of focal length 2.50 cm. (a) Determine the magnification of Mars as seen through this telescope. (b) Are the Martian polar caps right side up or upside down

Answer 1

a) -800

b) inverted

Step-by-step explanation:

Given

Focal length of the lens, f(0) = 20 m

Focal length of the eyepiece, f(e) = 2.5 cm = 0.025 m

The astronomical telescope uses two positive lenses: the first one being the objective, it forms the image of a distant object at its focal length, the second being, the eyepiece, it acts as a simple magnifier through which you view the image formed by the objective.

a) Magnification of Mars as seen through the telescope is

M = -f(0) / f(e)

M = -20 / 0.025

M = - 800

b) Since the magnification produced by the lens is less than 0 i.e m < 0, m = -800, suffice to say, the image is inverted.