Study of the X-ray baffle leak using an extended source - 1

PV Xrays from sources outside the field of view can enter the EPIC field of view. The Xray baffles in front still leak at some level out to offaxis anglesof about 1.5 degrees. The angular dependence and the level have been measured onground but need to be verified in orbit by one pointing with the source onaxisand four additional pointings with the source offset by 70 arcmin at fourdifferent azimuth angles. The source should be sufficiently bright, stable intime and should show emission lines to ease the analysis of the spectraldependence. A moderate spatial extent but less than the EPIC field of view isadvantageous. Such a source is the Tycho SNR. This proposal is for the onaxisposition of the programme. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]