The photo was taken by optician Blake Mitchell on December 15, 1946. Here is Blake's somewhat brief caption to the photo which he wrote on the back of the print:
I hope to get some more posts this week including a new episode of Palomar in Science Fiction, an update on the work being done on the Hale Telescope's mirror supports and more. Stay tuned.
The 200" disc tipped up for testing. A 50" pitch polishing tool in foreground.