Levenhuk Blitz 60 BASE Telescope

Barlow’s lens
A scattering lens placed in the focuser of a telescope before the actual eyepiece. It gives the effect of extending the focal length of the lens, which for visual observation gives the effect equivalent to using an eyepiece with a shorter focal length. Simply put - higher magnification.

The ratio of the focal length of an optical instrument to its diameter. It is a constant that determines the amount of light reaching the focal point of the main lens or mirror. In practice, the smaller the value of f, the better and more accurate the image we get.

Focal length [mm]
The distance between the focus of an optical system and the focal point of the optical system. It affects the magnification given by the optical system and the lens speed.