Some images of a medium size sunspot.

This sunspot was observed by P. N. Brandt (KIS) and G. W. Simon (PL/GPSS, Sac Peak) at the Swedish Vacuum Solar Telescope (SVST) at La Palma with the support of G. Scharmer (Stockholm).

The images show a few samples from a 4 ½ h observing series of the sunspot NOAA 7519 observed at approx. N05, E15 on June 5, 1993 with a fast real time frame selection system. Wavelength was 468 ± 5 nm. For better visibility of the umbral dots the images were treated with an unsharp mask.

The properties of the umbral dots in this sunspot were studied in cooperation with M. Sobotka (Astronomical Institute, Ondrejov) and G. W. Simon (Air Force Res. Lab., Natl. Solar Observatory, Sunspot, NM 88349, USA); they are published in 2 papers in Astronomy and Astrophysics (1997).