Astronomy
My 10 inch Mirror with a 1/48 P-V Wavefront Error @ 550 nm
In stead of making a single foucult test at the
end of the fine grinding, I mapped 320 points
on the surface of the mirror for each of which, I had made a foucult test,- 20
points along, 16 radials. From this information I could identify any radial
along which more polishing would be required, and mark the edge of the mirror
so that I could increase the length of the polishing stroke along that radial.
( The polishing stages are just finer grades of grinding.) I remapped
the mirror several times during polishing. As I approached the desired
Radius of Curvature, the Mirror was so perfect, I was afraid to
"figure" it.
I did however, and managed to shorten the
radius of curvature along the mirror's central axis by exactly 5.88 mm. the
correct amount being r / R or
5*5 / 108 = 0.2315 inches, which multiplied by 25.4 gives 5.8801 mm. My
Physics teacher, Mr. Walter Boldt, sent the mirror to the optical labs at the
University of British Columbia for aluminizing. When the mirror came back,
there was a note attached saying this was the most beautifully configured lens
they had ever received for aluminizing.
