I'm having some trouble understanding how a refracting telescope forms a magnified image for an object that is not assumed to be infinitely far away. I drew this ray diagram: enter image description here

And as you can see, a real and diminished image is formed. I would like to know whether or not this diagram is correct, and if not, what would be the appropriate diagram?

  • 2
    $\begingroup$ The relative placements of your lenses is wrong. The idea is, that the second lens creates a virtual image of an intermediate real image formed by the first lens. The magnification is then defined by the change in viewing angle when compared to the naked eye (of course a telescope cannot create a magnified real image of a planet or star, that would be pretty useless). See also: Wikipedia on magnification. $\endgroup$ – Sebastian Riese Dec 21 '15 at 14:42
  • $\begingroup$ the diagram per se is correct $\endgroup$ – scrx2 Dec 21 '15 at 15:09
  • $\begingroup$ Technically, a "telescope" does not produce a real image, just a magnified field-of view (smaller FOV, greater resolution). It's followed with a "camera lens" which produces the real image. $\endgroup$ – Carl Witthoft Dec 21 '15 at 16:47

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.