152/1200 ED apochromatic doublet refractor OTA

Describes the exact structure of the telescope thereby further subdividing the different types of telescope.

This is the distance between the objective lens or mirror and the focal point.

Describes the brightness of a star or point-shaped object, which can still just be distinguished by the telescope. The naked eye, for example, can make out stars with a magnitude of up to 6.

The telescope’s magnification should not exceed this factor, because otherwise the image will appear weak and dark.

Most telescopes are made of steel, aluminium or carbon fibre.

A telescope always displays an object upside down. This law of optics can only be compensated for by an erecting system. Erecting lenses, diagonal mirrors or Amici prisms provide you with an upright image. Diagonal mirrors provide an upright but back-to-front image and Amici prisms provide an upright and right-sided image.