Start > Foucault images of my first mirror (6" F5.5)
My first Mirror (6' f/5.5)
I did most of the grinding with my selfmade grinding machine.
At the finer stages 600/800/1200 I did some more wets by hand because the
machine seems to collect the grid in the center of the mirror.
Now the polish is in progress only with the machine.
Here are the first images from my foucault tester.
After four hours of polishing I tried a ring lap to have a
better progress at the edge. After using this for 1 hour I took
this first picture with a webcam:
After 30 min. polishing with tool on top (1/3 strokes) the surface seems to be smoother:
After 1.5 hours of polishing the same way I took several
pictures using my motor driven foucault tester.
The additional drawings in the pictures are from an early version of my image analysis program
which now controls the motors calculates ROC values of 100 zones on the mirror.
These curves show the brightness comparisons (inverted) of both sides at 100 zones.
The zone with correct ROC is where the line crosses the zero line in the middle.
The frame around the mirror shows where the program found the mirror edge.
Picture taken a little inside ROC (knife edge is at the right side)