Cassegrain Telescope
A compact reflecting telescope design combining a concave parabolic primary mirror and a convex hyperbolic secondary mirror.
Governing formula
f_effective = f_primary × (Magnification of secondary)
SI unit
Dimensionless
In depth
Light passes through a central hole in the primary mirror to an eyepiece behind it, folding long optical path length into a short, manageable tube.
Examples in the real world
The Hubble Space Telescope and major observatory reflecting telescopes utilizing Cassegrain architecture.