Previous abstract Next abstract
I discuss the current state of the Automated Plate Scanner (APS) program to obtain accurate astrometry from Palomar Oschin Schmidt plates. The principle plate materials being scanned by the APS (POSS~I, Luyten Red, POSS~II) all come from this one telescope. The transformation between plate and celestial coordinates is quite complicated near the edges of these plates. If it is intrinsic to the telescope, the astrometric methods we are developing for POSS I should be transferable to the Luyten and POSS II plates. The principle aim of this presentation is to foster further discussion amongst the various groups who are presently grappling with the peculiarities of Schmidt plate astrometry.