Klevtsov telescope
The Klevtsov telescope is a reflector telescope that was constructed by the Russian Juri A. Klewzow. Like the Maksutov telescope (and similar to the Cassegrain telescope ) it has a spherical primary mirror that is pierced in the center. The Klevtsov telescope also has a meniscus-shaped lens with which the spherical aberration of the main mirror is corrected. The combination of lenses and mirrors makes it a catadioptric system .
In contrast to the Maksutov and Schmidt-Cassegrain telescopes , the Klevtsov telescope is open at the front (like a Newton telescope ): the optical correction element is not located at the front tube opening, but is mounted on the inside of the secondary mirror. The secondary mirror is designed as a Mangin secondary mirror . The correction lens has the same diameter as the secondary mirror and is therefore significantly smaller than in a Maksutov telescope.
The beam path runs from the main mirror through the correction lens to the Mangin secondary mirror, on the back of which the light is reflected. The rays emerge from the glass of the Mangin secondary mirror, pass through the correction lens and are guided through the hole in the main mirror to the eyepiece .
In principle, the Klevtsov telescope has similar advantages as a Maksutov telescope . Because of the smaller correction lens, however, it is significantly lighter (and cheaper) than a Maksutov telescope with the same aperture and is therefore also suitable for larger apertures. One advantage over the Maksutov telescope and similar catadioptric systems is the tube that is open at the front. This minimizes thermal problems (temperature adjustment of the mirror and corrector to the outside air, convection in the tube). However, it is disadvantageous that the correction element must be manufactured and adjusted with particular precision, since optical errors have a greater effect because of the two-time beam passage and because of its small size. Another disadvantage is that the secondary mirror and corrector must be held by struts, since no glass element occupies the full opening in the front part of the tube; this leads to image artifacts due to light diffraction on the struts.
Similar variants
- Robert J. Magee has proposed a system in which the corrector consists of a lens cemented to the Mangin mirror.
- Ralph W. Field describes a telescope that places a meniscus-shaped corrector in front of an ordinary secondary mirror.
Individual evidence
- ↑ Archived copy ( Memento of the original dated September 12, 2006 in the Internet Archive ) Info: The archive link was inserted automatically and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Archived copy ( memento of the original from September 20, 2009 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
Web links
- http://www.quadibloc.com/science/opt02.htm Kinds of Telescopes (in English)