On May 7, 1991, several ground-based instruments have been coordinated to observe AR 6615 (S10-W26), before and during the flight of the SERTS rocket experiment (Schmieder et al.,1992):
– Imaging spectroscopy (MSDP) at the VTT telescope of Tenerife (collaboration Paris-Meudon and KIS Freiburg). H
1 are observed simultaneously in 2D fields, with 9 and 11 wavelengths respectively (Mein, 1991).
– High resolution “white light” pictures (around 4686Å) at the Swedish Vacuum Solar Telescope (SVST) of La Palma (Scharmer et al., 1985).
We present below some data from both instruments. Magnetic field maps are also available from the Huairou magnetograph (China), and from the GCT telescope (KIS/Tenerife).