The beginning of observations of large-scale solar magnetic fields at the Sayan Observatory: instrument, plans, preliminary results

Until recently, the investigations on large-scale fields have been limited to analyzing the distribution of the magnetic field radial component. At the Sayan Solar Observatory a telescope and a system of measurement of large-scale magnetic fields and of the large-scale field of line-of-sight velocities in the Sun's photosphere has been developed. The instrument permits the following programs of synoptic observations of large-scale structures: 1. Magnetograms of a large-scale magnetic field with a 3' resolution and 0.1-0.2 Gs sensitivity. Each magnetogram is taken within about 20 minutes. 2. Solar disk magnetograms as half-tone images of the magnetic field distribution with 15 Gs sensitivity and an 8x8'' resolution. Each magnetogram is taken within 5 minutes. 3. Measurement of a mean magnetic field of the Sun as a star with about 0.1 Gs sensitivity. The time of measurement is 10 to 20 minutes. (Auth.)