Increasing the resolving power of a telescope

  1. I have a toy telescope, very poor objective aperture like 30mm, the image is very poor.

    I was wondering if I could increase it's resolving power by placing a convex lens with a larger aperture in front of the objective lens?

    The larger lens should converge more light rays onto the objective giving more light.

    I understand that the telescope is made for parallel rays but wont decreasing the distance to the eye piece compensate?
  2. jcsd
  3. Andy Resnick

    Andy Resnick 5,781
    Science Advisor

    You are thinking mostly correctly, but the increased aberrations from doing what you suggest would likely degrade the image further.

    What you really need is an increased numerical aperture (decreased f-number), and you are probably better off just getting a better telescope, rather than spending that time and money improving a poor quality instrument.
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