The secondary mirror, unlike a Schmidt cassegrain, is an aluminized spot on the back of the corrector which serves to reflect the light rays backward through the hole in the primary.
(The secondary mirror; is; an aluminized spot on the back of the corrector) (the corrector; serves; to reflect the light rays) (the corrector; to reflect; the light rays backward through the hole in the primary)
The secondary mirror the corrector the corrector
is serves to reflect
an aluminized spot on the back of the corrector
to reflect the light rays
the light rays backward through the hole in the primary