Improving the telescope guiding with field stabilization on the Very Large Telescope/Unit Telescopes

Abstract

Acquisition and guiding services have been provided at major telescopes in order to improve the quality and efficiency of scientific observations. Field stabilization (FS) is an essential component of the telescope control system. With the arrival of new-generation instruments, the stabilization requirements have increased. Higher correction frequency is required to minimize the residuals. A major re-engineering of the CCD acquisition software now enables an increase of the operational frequency from 25 to 87 Hz. We analyze and discuss the performances of FS at various frequencies on the Very Large Telescope with its 8-m telescopes including the Adaptive 8-m telescope equipped with a deformable secondary mirror. We will report on the analysis of the residuals in function of several operational key parameters, e.g., the loop frequency, the magnitude of the selected telescope guide star, etc. We will also discuss the possible automatization of the FS during night operations.