Local Correction of the Light Position Implemented on an FPGA Platform for a 6 Meter Telescope

Abstract

The low-frequency component of the distortions caused by both the atmospheric turbulence and the behavior of the telescope itself has been studied. A corrector for the position of the center of the star image has been developed and is being used in front of the high-resolution Echelle spectrograph on the 6 m telescope of the Special Astrophysical Observatory, Russian Academy of Sciences. To speed up the calculations and to increase the bandwidth, a laser beam angular stabilization system based on an FPGA platform is considered. The system consists of two tip-tilt mirrors and two quadrant photodiodes. The FPGA analyzes the signals from the photodiodes, calculates and then applies the voltages to the piezo-driven tip-tilt mirrors to minimize the displacement of the beam on the photodiodes. The stabilization system was developed as a part of the adaptive optical system to improve the efficiency of the high-resolution Echelle spectrograph.