Telescope Magnification Calculator

Objective lens diameter (mm):

Eyepiece focal length (mm):

Telescope Magnification Calculator

A Telescope Magnification Calculator helps determine the magnifying power of a telescope. The formula used to calculate the magnification power is the focal length of the telescope’s objective lens or primary mirror, divided by the focal length of the eyepiece being used. The magnification power can be adjusted by changing the eyepiece.


Magnification = Focal Length of Objective Lens / Focal Length of Eyepiece


If the telescope’s objective lens has a focal length of 1200 mm and you are using an eyepiece with a focal length of 20 mm, the magnification power would be:

Magnification = 1200 mm / 20 mm = 60x

Therefore, the telescope magnification would be 60x.

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