RESULTS OF MAGNETOGRAPHIC LINE-RATIO MEASUREMENTS

We adapt the line-ratio method to magnetographic measurements. The method yields information on inhomogeneous magnetic fields without resolving their fine structure. Supplementing the magnetic field measurements, each day several polarization calibrations were made to eliminate the influence of the instrument. Modified theoretical calibration curves served for the transformation into inclination angles and magnetic field strength. The circular polarization along some scans across two sunspots practically shows the same distributions in both wings. The linear polarization in these selected scans attained only about half as large values as the circular polarization. The maxima were found in the steep parts of the V distributions. Comparing the two lines a similar behaviour was found, but also differences of about 0.5 percent, which may be significant. The inclination angles determined by means of calibration curves also seem to be more accurate than those calculated from transverse and longitudinal magnetic field components. As an evidence the results in sunspots and faculae are quoted. The values separately determined for the lines scattered only by 3 respectively 7 degrees from the mean values. In the darkest points of an umbra practically accordance of inclination and heliocentric angle was obtained, i.e., the magnetic vector was directed perpendicular to the surface. From the amount of the circular polarization in faculae comparing it with results of model calculations the filling factors were determined. Our results arranged between 3 and 11 percent nearly agree with the values by SOLANKI and STENFLO (1984). The line-ratio method in the version adapted to our magnetograph yielded from the V ratios in sunspots an average of 1880 G, but from the Q0 ratios an average of 2240 G. In faculae both values are practically identical and run to 1980 G. These results show that the line-ratio method is superior to the old reduction procedure of magnetographic measurements.