A study of systematic positional errors in the SPM plates
Lindegren, L.; Crifo, F.; Platais, I.; Jahreiß, H.; Girard, T. M.; van Altena, W. F.; Ma, W. Z.
United States, China, Sweden, France, Germany
Abstract
The high-precision reference system defined by the Hipparcos 30-month solution is used to evaluate the presence of potential systematic errors in star positions on the Southern Proper Motion program (SPM) plates. The SPM plates modeled into the Hipparcos positions show a consistent magnitude equation which can be explained by lens decentering. Noticeable cubic terms are present in the plate model, perhaps also related to the objective lens alignment. In general, the Hipparcos positions are very powerful for detecting systematic errors in wide-field photographic astrometry.