The ESO Off-line Telescope Testing Technique Illustrated with Results for the MPIA 2.2 m Telescope II

Abstract

The ESO test device is based on the proposal of ShackFig. 1 shows the principle of this method, which we call the SHACKHARTMANN (S-H) method as it is derived from the well-known conventional Hartmann technique. The beam from the telescope focus (6) is transmitted by a beam-splitting cube (2) of high quality to a collimating (Fabry) doublet objective (3). This images the exit pupil of the telescope to the plane (4) where a special SHACK lenticular raster is inserted. Each lens of this raster then forms a point image of that part of the parallel beam incident upon it on to a photographic plate (5) placed at the focal distance of the raster lenses from (4). The angular aberration in the telescope image is thus transferred through the system and shows as a transverse displacement of the spots.