Microwave Receiving System Based on Cryogenic Sensors for the Optical Big Telescope Alt-Azimuth.

This article presents the results of evaluating the possibility of conducting radio astronomy studies in the windows of atmospheric transparency ~100, ~230, and ~350 GHz using the optical Big Telescope Alt-Azimuthal (BTA) of the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS). A list of some promising astronomical tasks is proposed. The astroclimat conditions at the BTA site and possible optical, cryogenic, and mechanical interfaces for mounting a superconducting radio receiver at the focus of the optical telescope are considered.

High-resolution astronomical spectrograph design method with a single echelle grating.

The paper presents a method for calculation of the main paraxial and energy parameters of a high-resolution astronomical spectrograph with a single echelle grating in a wide spectral range, without cross-dispersion elements. We consider two variants of the system design, namely, with a fixed grating (spectrograph) and with a movable grating (monochromator). Based on the analysis of the spectral resolution dependence on the echelle grating characteristics and the collimated beam diameter, the limits of the achievable maximum spectral resolution of the system are determined.