I need help comparing the length of a refracting telescope with the sum of the focal lengths of its two lenses?
Sunday, December 12th, 2010 at
3:27 pm
Can you help me compare the length of a refracting telescope with the sum of the focal lengths of its two lenses?


US $34.99



The distance between the lenses is the length of the telescope so L = f1 + f2.