How do images differ in a telescope as the focal length differs?

Posted on October 22, 2009 by admin

Suppose that you have 2 telescopes with the same aperture, Telescope A has a focal length 3 times longer than that of telelscope B. How would the image size differ in telescope A from that in telescope B?

The focal length of a telescope determines the magnification – all other things being equal…

Telescope A would have 3 times the magnification of B

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2 Responses to How do images differ in a telescope as the focal length differs?

  1. David D says:
    October 23, 2009 at 5:08 am

    The focal length of a telescope determines the magnification – all other things being equal…

    Telescope A would have 3 times the magnification of B
    References :

  2. injanier says:
    October 23, 2009 at 5:32 am

    The image projected at the focal plane will be 3 times larger in telescope A. Through the eyepiece, you will get identical images if you use an eyepiece in telescope B with 1/3 the focal length of the one in A.
    References :