Modified Dall–Kirkham telescope
- Modified Dall–Kirkham telescope
-
The Modified Dall–Kirkham telescope utilizes an elliptical primary and spherical secondary mirror as in the conventional Dall–Kirkham configuration, but also includes two lens elements ahead of the focal point to improve off-axis image quality. The primary mirror conic constant is slightly different than that for a conventional Dall–Kirkham and must be optimized along with the lenses during design. The usable field is much better than the Ritchey–Chrétien telescope without corrector, and over very wide spectral bands, typically 0.38 to 0.95 micrometres if the corrector is made of quartz. The Ritchey Chrétien System with corrector has a better and bigger field.
Such a telescope was designed by Rosin and Wynne after WWII. The performances are equal or better than the Ritchey–Chrétien telescope. The spherical secondary can be fringe tested against the spherical convex surface or tested from behind. This is markedly an advantage over the hyperbolic secondary of the Ritchey-Chrétien design.
Another advantage of either the basic Dall-Kirkham or the Modified Dall-Kirkham design is that collimation of the convex spherical secondary mirror with respect to the optical axis of the primary mirror is almost trivial, because there is no single defined axis of a sphere. Any line that runs through the center of the sphere can be an axis.
References
See also
Categories:
- Astronomical observatory stubs
- Telescope types
Wikimedia Foundation.
2010.
Look at other dictionaries:
Modified Dall-Kirkham telescope — The Modified Dall Kirkham telescope utilizes an elliptical primary and spherical secondary mirror as in the conventional Dall Kirkham configuration, but also includes two lens elements ahead of the focal point to improve off axis image quality.… … Wikipedia
Reflecting telescope — 24 inch convertible Newtonian/Cassegrain reflecting telescope on display at the Franklin Institute. A reflecting telescope (also called a reflector) is an optical telescope which uses a single or combination of curved mirrors that reflect light… … Wikipedia
List of telescope types — There are three main types of optical telescopes and these are divided into subgroups. They all have their different advantages and disadvantages and they are used in different areas of astronomy.Refractors (Dioptrics) * Non achromatic *… … Wikipedia
Apollo Observatory — Infobox Observatory name = Apollo Observatory caption = organization = Miami Valley Astronomical Society location = Dayton, OH coords = altitude = weather = established = closed = website= [http://www.mvas.org/facilities.html] telescope1 name =… … Wikipedia
Miami Valley Astronomical Society — The Miami Valley Astronomical Society (MVAS) began in 1918 as the Dayton Astronomical Society (DAS), and was the first formally organized group of amateur astronomers in the Dayton area. Founded around the time of the first world war, one of its… … Wikipedia
Spiegelteleskop — „Leviathan“, um 1860 Spiegelteleskope sind Teleskope, die als Objektiv einen Hohlspiegel besitzen. Bei den meisten Bauformen sind auch andere optische Elemente als Spiegel ausgeführt. Spiegelteleskope werden überwiegend für astronomische… … Deutsch Wikipedia
