Rapid fabrication strategy for Ø1.5 m off-axis parabolic parts using computer-controlled optical surfacing.

摘要: Off-axis parabolic parts (OAPs) or quasi-OAPs are mostly frequently used in large optical telescopes. Compared to the stressed mirror polishing, computer-controlled surfacing (CCOS) other subaperture tools provide more flexibility. However, fabrication efficiency needs be promoted tactical ways. In this paper, we present a aperture CCOS lap equipped with compound motion unit and go through grinding pre-polishing its figure errors. A CCOS-based heterocercal tool is first optics restrain edge effects. fine polishing stage, corrective smoothing, ion beam figuring applied combination finish. We experimentally test strategy on an O1.5  m OAP, as part of giant steerable science (GSSM) Thirty Meter Telescope. Finally, surface error OAP better than 1/50λ RMS (full aperture), mid-spatial frequency 0.64 μrad slope (effective aperture). The effective duration reduced 2 months.