Pasachoff, Jay M. Hopkins Observatory, Williams College, Williamstown, Massachusetts.
Pickles, Andrew J. Las Cumbres Observatory Global Telescope Network, Goleta, California.
- Sky surveys
- Related systems
- Schmidt-Cassegrain design and amateur use
- Links to Primary Literature
- Additional Readings
A fast, compact, wide-field optical system that uses a thin aspheric front lens at the center of curvature of a larger concave spherical mirror. The image is focused onto a curved focal plane between the two elements (Fig. 1). Schmidt cameras are sometimes used in microscopes, astronomical spectrographs, and projection televisions. The largest such devices can image several degrees of the sky and are known as Schmidt telescopes. The Estonian optician Bernhard Schmidt devised the scheme in 1930. The field of best focus is located midway between the lens and the mirror and is curved toward the mirror, with a radius of curvature equal to the focal length. Historically, film or photographic plates were bent to match this curved focus, and used to make the first all-sky survey pictures. Field-flattening lenses permit the use of charge-coupled devices (CCDs) in newer applications. Large mosaics of CCDs have replaced photographic emulsions in some applications, and large numbers of optical fibers have also been used in multiobject spectrograph configurations. See also: Astronomical imaging; Charge-coupled devices; Geometrical optics; Lens (optics); Mirror optics
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8500 articles and Research Reviews covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information