Magnification of the telescope


Optical magnification is the ratio between the apparent size of an object (or its size in an image) and its true size, and thus it is a dimensionless number.
A telescope uses its large objective lens to create an image of a distant object and then allows the user to examine the image closely with a smaller eyepiece lens thus making the object look larger.
An eyepiece, or ocular lens, is the lens that is closest to the eye when someone looks through the device. The objective lens or mirror collects light and brings it to focus creating an image. The eyepiece is placed near the focal point of the objective to magnify this image.
The angular magnification of the telescope is related to the focal length of the objective lens and the focal length of the eyepiece

Related formulas


MMagnification (dimensionless)
f0Focal length of the objective lens (cm)
fefocal length of the eyepiece (cm)