Imaging Performance of the XMM-Newton X-ray telescopes
  The in-orbit imaging performance of the three X-ray telescopes on board of the X-ray astronomy observatory XMM-Newton is presented and compared with the performance measured on ground at the MPE PANTER test facility. The comparison shows an excellent agreement between the on ground and in-orbit performance. 
B. Aschenbach, U. Briel, F. Haberl, H. Braeuninger, W. Burkert, A.   Oppitz, P. Gondoin, and D. Lumb