The Question is: An objective lens of a telescope has a 1.90 m focal length. When viewed through this telescope, the moon appears 5.25 times larger than normal. How far apart are the objective lens and the eyepiece when this instrument is focused on the moon?

Question

I know that the magnification equation is: normal near point distance(25) / focal length of the magnifying glass. However, I am confused on how I can use this to solve the problem. I would really appreciate your help! Thank You!

Answer 1

Oh wait, I just tried a different equation and want to confirm that this is correct: M = Fobj/Fep =>
Fep = Fobj/M ==> Fep = 19cm/5.25 = 3.62 + 19cm = 22.62 cm