POSS Statistics.

The search for supernovae on large Schmidt plates has been the standard method used by astronomers for decades before the advent of automated telescopes equipped with CCD cameras. French astronomer Christian Pollas success is based on this method and the used of a 90cm Schmidt camera. Supernovae are also currently found with the Palomar Oschin 48" Schmidt camera, on plates exposed mostly for other purposes (ie., POSS 2). Supernovae discoveries with the Palomar Oschin Schmidt are made on galaxies in the 14-18 magnitude range (graph n.1) and their brightness range has a peak around magn. 19. Although these instruments are beyond the reach of amateurs, the use of photography in supernovae search is still employed by some amateurs. Resolution and wide fields are a key for a successful photographic program. Graph n.1 Graph n.2