The in situ testing of an unpolished off-axis parabolic mirror with a vertex radius of 12.8 m, a diameter of 1.42 m, and an off-set of 1 m is described. Interferograms are shown that were obtained during the fabrication process by means of a lona-wavelength interferometer that uses a CW CO2 laser operating at a wavelength of 10.6 µm as the coherent light source.
J. C. Wyant,
C. R. Hayslett,
"Long-Wavelength Interferometer In The Optical Shop", Proc. SPIE 0192, Interferometry, (25 December 1979); doi: 10.1117/12.957841; https://doi.org/10.1117/12.957841