Celestron PowerSeeker 50 AZ Refractor Telescope

The distance from the optical center of a lens to its image plane when the lens is set at its working focus, expressed in a standard length unit such as millimetres or centimetres. It indicates the angle of view and zoom capability of an optical system and helps users compare lenses with different fixed focal lengths.

The optical magnification factor of a device such as a camera lens, binoculars or telescope. It indicates how many times larger an object appears compared to its actual size when viewed through the product. Values are expressed as a multiplier (e.g., 2x, 10x).