Fine Guidance System.

The Fine Guidance System (FGS) is intended for precise pointing and stabilization of the telescope during a scientific observation session.

The FGS consists of 3 guiding sensors located near the central part of the telescope focal surface, and the common Data Processor Unit (DPU). Every sensor is based on 1 megapixel radiation hard CMOS image sensor STAR 1000, fabricated by Fillfactory .The Master catalogue for the FGS is stored in the Data Processor Unit and contains coordinates of guiding stars over all the sky down to 17th R magnitude.

Sensitive surfaces of guide sensors are located close to the spectrographs entrance slits on their cases. It provides high stability of mutual position of the entrance slits and GS receivers.

Main characteristics of the FGS are presented in the following table:

Pointing and stabilization accuracy0.03"
Period of information updating0.5 - 2 sec
Spectral range450 - 750 nm
Guide starsUp to 17 magnitude
FoV3x3 arcmin

The Fine Guidance System is under development by the Russian Space Research Institute (IKI RAS).