Regular observations of the Sun have started at the first stage of the multiwave Siberian Radioheliograph (SRH). It is a T-shaped interferometer currently consisting of 48 antennas observing in a 4-8 GHz operating frequency range with a 10 MHz instantaneous receiving band. The SRH’s antennas are installed on the central antenna posts of the Siberian Solar Radio Telescope (SSRT: Grechnev et al., 2003). The maximum baseline is currently 107.4 m providing an angular resolution up to 70 arc seconds.
Figure 1. The central part of the SRH antenna array and the northern arm of SSRT.
SSRT, which is transformed into SRH, is a cross-shaped interferometer consisting of East-West and South-North equidistant linear arrays of 622.3 m, each with 128 antennas. The images are formed by scanning the Sun, firstly, due to the simultaneous receiving at different frequencies in the 5.67-5.79 GHz band and, secondly, due to Earth’s diurnal rotation. Thus, SSRT can produce images every 2-3 minutes at best.
SRH uses a different imaging principle, a parallel Fourier synthesis (Lesovoi et al., 2014). Both circularly-polarized components are measured. The observing frequencies are set by software. The time to switch from one frequency to another is currently about 2 ...