Under some circumstances the positions of X-ray sources can appear
to drift by 0.1 to 0.4 arcsec during an observation. This occurs due
to thermal alignment changes in the fiducial transfer system periscope
related to overall spacecraft heating. The list below shows all
observations in the archive for which the X-ray image data may have
drifts of more than 0.1 arcsec. Please contact the CXC Helpdesk for
information on improving the aspect image reconstruction for an observation in this list.
|obsid||obi||expected drift (arcsec)||aspect pipeline version||last aspect processing|