MAINTAINING THE EPHEMERIS OF THE GEMINGA PULSAR UNTIL GLAST

The Geminga pulsar is unique among gammaray pulsars in having a precise andcontinuous, phaseconnected ephemeris from 1973 up to the present. Since thedemise of the Compton Gammaray Observatory in June 2000, the only practicalmethod of maintaining Geminga.s ephemeris is with Xray observations. Followingthe initial XMM observation of Geminga in April 2002, we propose to make shorteradditional observations approximately once per year until 2006, when GLAST willresume the gammaray timing of Geminga. The principal scientific need for aphaseconnected ephemeris is to provide an absolute phase reference forgroundbased observations, in particular, for our own efforts to detect opticalpulsations using a phasebinning CCD camera at Palomar Observatory. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]