Apochromatischer Refraktor AP 61/360 ZenithStar 61 Blue OTA

The weight of the tube is critical for the correct choice of mount.

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

Refractors with little chromatic aberration.

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.

Is the ratio of the aperture to the focal length of a telescope.

There are basically two different types of telescope. A distinction is made between refractor (lens) and reflector (mirror) telescopes.

A refractor with two lenses. Compared to an achromat, it displays significantly less chromatic aberration and more contrast.

There are basically two different construction types: the rack and pinion focuser and the Crayford focuser.

Are mainly differentiated between equatorial and altazimuth. A special type of altazimuth mount is the Dobsonian mount.

Optical aid to correct aberrations.

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.

Telescopes that are supplied as a complete system and are easy to operate.

Telescopes suitable for a fixed mount, whether that is in the garden or an observatory.