Uploaded November 2011 | Updated September 2026, 2 weeks ago
I use my Foucault tester to get an idea of how the surface polishing is going. The test revealed that I'm getting a case of "Dog Biscuit". It appears my pitch lap is too hard and is not polishing the surface as it should. Time to pour a new lap and start polishing again. The shadows are not achieved by moving the knife edge, but by moving the actual camera... no need for precise shadow readings yet.
I use my Foucault tester to get an idea of how the surface polishing is going. The test revealed that I'm getting a case of "Dog Biscuit". It appears my pitch lap is too hard and is not polishing the surface as it should. Time to pour a new lap and start polishing again. The shadows are not achieved by moving the knife edge, but by moving the actual camera... no need for precise shadow readings yet.
