Telescopes with very large diameter or with wide fields require convex secondary mirrors that may be
many meters in diameter. The optical surfaces for these mirrors can be manufactured to the accuracy
limited by the surface metrology. We have developed metrology systems that are specifically optimized
for measuring very large convex aspheric surfaces. Large aperture vibration insensitive sub-aperture
Fizeau interferometer combined with stitching software give high resolution surface measurements. The
global shape is corroborated with a coordinate measuring machine based on the swing arm profilometer.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.