Astronomical telescope test with Puntino: measure stress due to supports

SpotOptics wavefront sensor Puntino and SenSoft software were used for analyzing a 1.5m mirror telescope in 1996. Since the Telescope has an annular pupil, the Annular Zernike polynomials were implemented in SenSoft together with the Standard Zernike, Fringe Zernike and Seidel polynomials. After the calculation of the Annular Zernike aberration terms, the wavefront was reconstructed mathematical removing all of the Zernike terms (this is a feature of our software Sensoft): the resulting mirror surface map (left) clearly follows the mirror support map (right).

The telescope has a thin primary mirror ( 500 Kg weight). We are able to see details as small as 268 nm (Peak to Valley of the graph).