The Optical Monitor on ESA's XMM Observatory Lumb, D. H. ; Còrdova, F. A. ; Leisawitz, D. T. ; Robinson, C. ; Thompson, R. ; Ho, C. ; Priedhorsky, W. Abstract Publication: Bulletin of the American Astronomical Society Pub Date: September 1991 Bibcode: 1991BAAS...23.1349L