The Vacuum Tower Telescope (VTT) at Tenerife has been used together with a polarimeter in front of a two-dimensional imaging spectrometer with a Fabry-Perot interferometer. The spectrometer has been described by Bendlin et al. (1992) and Bendlin et al. (1995), the remaining instrumentation, calibration, and data reduction by Horn et al. (1996). Some parameters of the setup were: 384×286 pixel CCD-camera (0.2” per pixel); resolution for the images better than 0.8”; filtergrams in the photospheric spectral line Fe I 6173.4 Å with Δλ = 10.9 mÅ; 45 filtergrams for each scan; 127 scans within 114 min. Δt = 54 s. White-light images from the same field of view were taken strictly simultaneously to all narrow-band pictures to correct for image blurring and motion.

The present observations were obtained on July 20, 1994, and were focused on the main spot of the active region NOAA 7757, 30° NE from the disk center.