Ritchey-Chrétien telescope
Ritchey-Chrétien is a type of
astronomical telescope. It is a specialized Cassegrain reflector with the advantage that it is
coma free. This is why almost every professional
reflector telescope in the world is of the Ritchey-Chrétien design.
It was invented by
George Willis Ritchey and
Henri Chrétien in the early
1910's.