089020

We propose to re-observe G21.5-00.9 on 9 raster positions comma covering the full range of off-axis angles from 0 to 13 arcmin comma and carefully selecting the regions on both MOS2 and PN comma with no chip gaps and bad columns. We shall cover all MOS2 CCDs and in addition we add 3 more raster points in the central one. Based on the previous observations comma using an exposure time of 10 ks per observation comma we shall achieve excellent statisticsdoublePoint expected 4000 counts in the hard band CORCHETE_OPEN2-10CORCHETE_CLOSE keV comma sufficient to allow derivation of the vignetting with small uncertainties. G21.5-00.9 has an excellent visibility for full revolutions in March-April 2021 comma thus all 9 rasters could fit into one revolution.