A new vectormagnetograph is described that measures all components of the magnetic field vector strictly simultaneously. The azimuth of the direction of the field is continuously obtained during the observation by means of a servo circuit. As a first step of data recording a photographic method is applied which presents all 5 quantities (longitudinal and transverse component of the field vector, azimuth, Doppler shift and intensity) in the form of maps. Several methods of calibration are discussed in detail. For stronger fields the calibration turns out to be particularly difficult. The sensitivity obtained is 4 gauss using a scanning spot of 3″ × 3″ and a time constant of 1 sec. This value agrees with the shot-noise of the multipliers which can be inferred by taking the light transmittance of the whole instrument into consideration. Transverse fields have been measured with a sensitivity of 130 gauss (300 gauss, if the random deviation of the azimuth is < 10°). In this case the scanning spot covered 5″ × 5″, the time constant being 3 sec. A series of vectormagnetograms is presented which was obtained during a 2B-flare event in a centre of activity. The field configuration is discussed with regard to the position of the flare. © 1969 D. Reidel Publishing Company.
