The Maksutov-Cassegrain catadioptric is a variant of the Cassegrain; section of both mirrors is spherical while the top optical path, there is a meniscus corrector with both spherical surfaces, whose function is to introduce a quota equal to the same spherical aberration produced by reflective optics, but of opposite algebraic sign. In classical Maksutov-Cassegrain (configuration Gregory ) the secondary mirror is aluminum is obtained, the central portion of the internal meniscus corrector , this trick will greatly reduce the central obstruction and simplifies both the optical and mechanical (not This secondary mirror he nor his support) to the benefit of a better contrast. The other side of megaglia however, is the need on the optical plane of the presence of a long focal length (f/13 and beyond) as the curvature of the meniscus requires a powerful multiplier to the secondary. In the configuration
Ru-Mak but this is a secondary mirror with its support (as in Schmidt-Cassegrain), allowing to obtain reports of opening more universal (f/10...12)
The strengths of these instruments are compact (for the benefit of the frame and portability), the closed tube that reduces internal turbulence and aplanaticità that conjures the presence of spherical aberration.
A problem with these lenses can be represented by a long period of acclimatization heat mainly due to the thickness of the meniscus ; makers often make use of fans to speed Trade in temperature.
Basically, these tools are very valid for observations of objects in the solar system, the separation of double stars and even occasionally objects of the background sky, on the other hand often have a very small right field that would penalize the use of photography. However, the
Maksutov-Cassegrain variants Sigler and Simak is optimized for photography direct fire.
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