Abstract

New astrometric reduction of the USNO photographic plates of the planetary satellites

Jean-Pierre De Cuyper (Royal Observatory of Belgium (ROB))

J-E Arlot, V. Robert & V. Lainey (IMCCE - Paris Obs.) D. Pascu & N. Zacharias (USNO) L. Winter & G. de Decker (ROB)

An international collaboration has been set up between the USNO, the IMCCE of Paris Observatory and the Royal Observatory of Belgium (ROB) to make a new astrometric reduction of the USNO archival photographic plates collection of the planetary satellites in order to provide a better knowledge of their orbital motions. Hereto these photographic plates will be digitised with the new generation “DAMIAN” digitiser at the ROB. Providing an accuracy of the fitted positions of < 1 µm on the plates. We focus here on a subset of a few hundred photographic plates of the Galilean satellites, taken with the USNO 26-inch between 1967 - 1998. Specific procedures and algorithms are used to obtain a high accuracy position of each moon using the Tycho2, UCAC2 (20 –30 mas) and later the UCAC3 (10 mas) catalogues.

The general problem of analogue and digital data archiving will be discussed and a new low cost long term solution presented.

Mode of presentation: poster