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MAGNIFICATION
To determine the magnification of a telescope and eyepiece
combinantion, divide the telescope focal length be the eye-
piece focal length.
Magnification (x) = Telescope Focal Length (mm)/Eyepiece
Focal Length (mm)
Ex: 17.5mm Eyepiece with a 60x600mm telescope.
Magnification =600mm/17.5mm
Magnification = 34.2x
FOCAL RATIO
To determine the focal ratio of a telescope, divide the focal
length of the telescope by the aperture.
Focal Ratio (f/x)= Telescope Focal Length (mm)/Aperture (mm)
Ex: Focal Ratio of a 60x600mm telescope.
Focal Ratio (f/x)= 600mm/60mm
Focal Ratio (f/x)= F/10
ASTRONOMY FORMULAE FOR YOUR
ZHUMELL ZENITH TELESCOPE