For the purpose of validate a new stitching algorithm —Sub-Aperture Stitching and Localization algorithm(SASL algorithm)

this paper describes a measuring and figuring experiment of the SiC flat mirror whose shape is elliptical (225mm long in major axis

161mm long in minor axis). First

a comparative experiment of sub-aperture stitching test with full-aperture interferometry on a 100mm diameter flat mirror is presented

in order to determine the parameter of the algorithm the precision requirement of the stitching equipment. This is followed by a successful sub-aperture stitching process for the SiC flat mirror

which contains 5 iterations of Ion Beam Figuring (IBF) process and the ultimate testing. In this process

sub-aperture stitching test offers the surface error data precisely to IBF

which ensures the quick convergence of the process to achieve a final surface error of 50nm RMS. The experiment shows that SASL algorithm relaxes the precision requirement of the stitching equipment and reduces the influence of stitching process to the result.