This is the mirror blank for the Hale Telescope at Mt Palomar. It doesn’t look like a mirror because it hasn’t been silvered and polished.
This 5-meter, 36-ton disk was cast at the Corning Glass Works in 1934, and is made of their brand-new miracle glass, Pyrex. The hot glass caused part of the frame so soften, with parts of it floating up into the hot Pyrex, and the mirror was cracked and ruined.
A second minor was successfully cast and is still in use at Mt. Palomar. This first mirror is in the Corning Glass Museum. When a new museum was built, it was built around the mirror, which was easier than trying to shift a 36-ton mirror without breaking it.
If you look in the central hole, you’ll see a silhouette of Kathy sitting cross-legged and waving at you.
