Grinding of the two mirrors started September 12, 1999. We used the club's "Modified Hindle" mirror grinding machine. Since the machine had not been used in a number of years, we had to excavate and clean up the grinding machine.
After these steps were completed, we were able to start rough grinding the mirror. After the rough grinding was completed, the fine grinding and prepolish were done.
While we were doing the prepolish, we prepared the pitch lap. This is used for both the polishing and figuring.
The grinding and initial polishing result in a roughly spherical mirror, but we actually want a parabolic mirror. For this, we start using the Foucault tester. We started testing the mirrors early, before they were even fully reflective. While early tests are not all that useful, they are satisfying in that you can watch as the test images get better and better and .... It really helps to keep spirits up that all of the work is really worth it.
More testing showed that one of the mirrors had a problem. We had to back up a step for that mirror, but went on to the figuring stage for the other. It soon showed good results, and the first mirror caught up rapidly, although there were a lot of "two steps forward, one step back" episodes for both mirrors.
And then, finally, finally, finally, we were done.