Definition of Cassegrain telescope in US English:

Cassegrain telescope


  • A reflecting telescope in which light reflected from a convex secondary mirror passes through a hole in the primary mirror.

    • ‘Visitors can also see the University Observatory, which houses a 14 inch Schmidt Cassegrain telescope with a cooled CCD (Charge Couple Device) camera.’
    • ‘Easy portability and precision optics are hallmarks of Cassegrain telescopes, and Orion has some of the finest.’
    • ‘In an all-reflective Cassegrain telescope (usually called a Classical Cassegrain), there is no corrector lens.’
    • ‘The tube length is very long compared to a Cassegrain telescope of the same effective focal length.’
    • ‘A correcting plate (a lens) was added in 1930 by the Estonian astronomer and lens-maker Bernard Schmidt, creating the Schmidt-Cassegrain telescope which minimized the spherical aberration of the Cassegrain telescope.’


Late 19th century: named after N. Cassegrain (1625–1712), the French astronomer who devised it.


Cassegrain telescope

/ˌkasəɡrān ˈteləskōp/