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Glossary > Telescopes > Optics > Type of build

Glossary | Telescopes | Optics | Type of build

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

Mirror telescope or refracting lens telescope? Schmidt-Cassegrain or Maksutov? Anyone faced with these agonizing questions before buying a telescope needs to find out about the advantages and disadvantages of the different design types.

Refracting lens telescope:

  • Fraunhofer Achromat: classic principle of a refractor, but with chromatic aberration.
  • ED Apochromat: two- or three-lens refractor with an ED lens that reduces the most chromatic aberration and ensures maximum contrast. Among these refractors there are also some very well-corrected three-lens optics that correct chromatic aberration and field curvature and so are very suitable for astrophotography.

Reflector mirror telescope

  • Newtonian Reflector: classic telescope, named after Isaac Newton, with a main mirror and a secondary mirror. Simple and proven system.
  • Maksutov Cassegrain: system consists of a main mirror and a secondary mirror, and a meniscus correction lens.
  • Schmidt-Cassegrain: similar to the Maksutov, but instead of the correction lens, a Schmidt plate sits in front of the optics in order to correct chromatic aberration.

More information:


Meade's ACF optical design eliminates the typical aberrations of all mirror optics.


An achromatic is a refracting telescope (refractor), which consists of two lenses. It is the classic refractor design.


Refractors with little chromatic aberration.


Telescopes that are suitable exclusively for astrophotography.


This telescope consists of a parabolic primary mirror with a central hole and a hyperbolic secondary mirror. In this way the construction can be kept as short as possible.


Celestron’s aplanatic EdgeHD optics revolutionized astroimaging.


Maksutov-Cassegrain telescopes have a compact design, but a very long focal length. At the front there is a Maksutov lens. These telescopes are very well suited for planetary observing.

Maksutov Newtonian

Maksutov Newtonian telescopes are built like a classic Newtonian telescope, but have a Maksutov corrector lens at the telescope opening. With this, coma is eliminated. The telescope has excellent imaging capabilities.


Reflector telescope with a secondary mirror at the beginning of the tube which redirects light to one side.

Schmidt Newtonian

A Schmidt Newtonian telescope is constructed like a Newtonian telescope, but includes a Schmidt corrector plate. Thus, this telescope is a closed system and there is no air turbulence in the tube.


A reflector telescope with a particularly compact design but a long focal length. In addition to two mirrors, it has a Schmidt corrector plate at the front.

Smart Telescopes

A smart telescope combines a modern telescope with sensor technology in an easy-to-use system.

Solar H-Alpha

With H-alpha telescopes you can observe prominences, flares and filaments on the Sun. Additionally, these telescopes have an etalon filter and a blocking filter. Caution: you can also buy versions without the blocking filter. You should never use these without a blocking filter.

Solar calcium

Calcium K solar telescopes make the lower atmospheric layers of the chromosphere visible at 393nm. This blue short-wave region shows other equally interesting details of the Sun. These telescopes are popular for use in photography.