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Thread: Eye relief

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    Default Eye relief



    What is eye relief and the difference between the different "mm"?

  2. #2
    WWPierre's Avatar
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    Default

    Hi Martin, welcome to the forum. Please tell us a bit about yourself.

    Eye relief is the distance your eyeball is from the first piece of glass in an eyepiece. If you need to wear glasses to observe, (astigmatism) you need higher eye relief to leave room. 15-20 mm works for this astigmatic.

    The "mm" is the focal length of the eyepiece. Eyepiece F/Ls range between about 3 or 4 mm to around 50. The focal length of the eyepiece divided into the F/L of the scope gives the magnification. A 10mm eyepiece on a 650 mm scope gives a magnification of 65X.
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    Default

    Quote Originally Posted by WWPierre View Post
    Hi Martin, welcome to the forum. Please tell us a bit about yourself.

    Eye relief is the distance your eyeball is from the first piece of glass in an eyepiece. If you need to wear glasses to observe, (astigmatism) you need higher eye relief to leave room. 15-20 mm works for this astigmatic.

    The "mm" is the focal length of the eyepiece. Eyepiece F/Ls range between about 3 or 4 mm to around 50. The focal length of the eyepiece divided into the F/L of the scope gives the magnification. A 10mm eyepiece on a 650 mm scope gives a magnification of 65X.
    Hi Martin ... Welcome aboard the forums ...
    YUP ...What he said ... Good explanation there wwpierrie ....
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