Mirrors at the birth of Aphrodite

The first reflecting telescope was invented in 1663 by James Gregory, but was never popularised because the mirrors were too difficult to manufacture at that time. A slight variation on the principle, the Newtonian telescope, was first recognised in 1672 by its namesake, and was a most dramatic step forward in the observation of the stars. Even today the Newtonian telescope is perhaps the most economical and popular instrument of amateur astronomers. The Schmidt catadioptric telescope was not devised until 1930, and is a variation on the Newtonian telescope. In a Schmidt telescope, light first strikes a corrector plate that is essentially a lens, and then strikes a concave mirror. The reflected light is focused upon a film plate within the column of the original light beam. One of the principal purposes of the initial lens in the Schmidt telescope is to eliminate spherical aberration, but a simple bivalve mollusc had this elegant design as much as 500 plus million years ago, and still uses this system.

When you envision scallops, you probably imagine the painting of Aphrodite’s birth from the sea foam on a giant …