2005/11/02 by Willy Langeveld, Langeveld, Willy
Physics and Astronomy · #Adaptive optics and wavefront sensing #Astronomy and Astrophysical Research #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0511058
11 pages, 8 figures
arxiv created 2005/11/02 · arxiv updated 2009/12/01
In this note I describe an inexpensive and simple laser-based method to measure the flatness of the LSST focal plane assembly (FPA) in situ, i.e. while the FPA is inside its cryostat, at -100 C and under vacuum. The method may also allow measurement of the distance of the FPA to lens L3, and may be sensitive enough to measure gravity- and pressure-induced deformations of L3 as well. The accuracy of the method shows promise to be better than 1 micron.