A Telescope with a Cassegrain Focus Reflects Light Through an Opening

Essay

A telescope with a Cassegrain focus reflects light through an opening in the primary mirror for measurement at a camera.The telescope's mirror therefore has a small hole in it where light cannot be collected.How much smaller is the light-collecting power of a telescope with a primary mirror of diameter 10 m and a circular hole with a diameter of 1 m than an identical telescope without such a hole?