The SCORPIO-2 Focal Reducer Control System

A. E. Perepelitsyn, V. R. Amirkhanyan, A. V. Moiseev

Transactions of IAA RAS, issue 53, 44–53 (2020)

DOI: 10.32876/ApplAstron.53.44-53

Keywords: instrumentation, observational tools, control systems

Abstract

There is often need to quickly change the telescope instrumentation during astrophysical observations, for instance it is a switchover from photometry to spectroscopy. Multimode devices with a changeable optical scheme allow switching between different observational methods with a minimal time loss. A properly constructed and automated control system plays an important role here. In this paper, we review the control system of SCORPIO-2 multimode focal reducer operating in the primary focus of the 6-m SAO RAS telescope. The typical architecture of the system allowing remote observations is presented. We summarize the principles of the focal reducer hardware level operation, the detailed design of a unit with phase-rotating elements for high-precision polarimetric measurements is considered. Some design features of the focal reducer and its individual units control scheme implemented on microprocessors are presented. The observational complex included 'SCORPIO-2 + calibration and guiding adapter + detector + telescope' is controlled by a compact computer built into the focal reducer body. The software package written on IDL to make remote control of the observational complex is briefly described. We show one of the possibilities to create a distributed system allowing remote observations from a single point using different instruments: multimode focal reducer, calibration and off-axis guiding unit, image acquisition system, observational data archiving system and telescope. The focal reducer control system allows collecting all the device elements into a single block, minimizing internal and external connections. Quick switching between different methods provides flexibility of observational programs choice for the current state of the atmosphere, thereby saving observation time.

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