B. A. Ioshpa

A new controlling system for the solar tower telescope of IZMIRAN: I. Guide

A new guiding system for the solar tower telescope is described. Two mutually perpendicular CCD arrays are used as photodetectors. The guide provides a positional error of no larger than 0.2″ in a frequency band of 0–10 Hz. The software allows for referring the spectrograph slit position to solar coordinate systems and provides for various guide operation modes.

Second version of the IZMIRAN solar spectromagnetograph. Part I. Instrument design

The second version of the IZMIRAN solar spectromagnetograph (SM), which is designed for measuring the full vector of the magnetic field and the line-of-sight velocities in the solar photosphere, is described. In contrast to the conventional schemes, the described SM uses the parallel analysis of the spectrum and polarization of optical radiation. The latter could be performed thanks to the method of precise calibration of circuits with multielement photodetectors. The new scheme of the SM allows measurements of the Stokes parameters for two magnetically active lines with an accuracy limited by only the quantum noise of photodetectors.

A new controlling system for the solar tower telescope of IZMIRAN: II. A solar image motion compensator

A solar image motion compensator for the solar tower telescope is described. Two mutually perpendicular CCD linear arrays are used as photodetectors. An algorithm for forecasting the system behavior is used for generation of correction signals. Analyzing the solar image motion data obtained using the compensator and without it has shown that, thanks to its use, the total image motion value decreases to 0.5″–0.6″ in a frequency band of 0–100 Hz, being close to the amplitude of noncorrelated image motion component. The compensator operates equally effectively in both the pointing and scanning modes.