Arcetri Technical Reports 13/1994

Servosystem analysis for adaptive optics

G. Roberto Aiello

Osservatorio Astrofisico di Arcetri

Abstract

This paper reports the results of a simulation used to help defining the servosystem's specifications for the adaptive optics. The model includes a sensor, a reconstructor and an actuator. Different types of perturbation both for tip-tilt and high order correction are considered.

The purpose of this paper is to define the rough specifications for the different system's components, and it is of course possible to choose different system's configurations when the telescope will deal with perturbations with other frequency components or a different residual will be required. There are many possible servoloop's parameters configurations that meet the requirements, and the strategy followed in this paper is to keep the smaller number of photons and longer integration time for the sensor, and still close the feedback loop to reduce the input perturbation to the desired residual value.

The parameters are calculated both for the TNG (Telescopio Nazionale  Galileo) and for the LBT (Large Binocular Telescope).