[kas-uh-greyn] 
| a reflecting telescope in which the light, passing through a central opening in the primary mirror, is brought into focus a short distance behind it by a secondary mirror. |
[kas-uh-grey-nee-uh
n] .| cassegrainian telescope | |
noun | |
| a reflecting telescope that has a paraboloidal primary mirror and a hyperboloidal secondary mirror; light is brought to a focus through an aperture in the center of the primary mirror |