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Progress in the Reduction of Old Astrometric Observations of the Natural Planetary Satellites

Dr. Vincent Robert, Paris Observatory, IPSA & IMCCE
When Apr 24, 2014
from 10:30 AM to 12:00 PM
Where USNO, Building 56, Large Conference Room
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Time:  10:30 (coffee/cookies);    Talk 11:00-12:00.

Abstract: 

A new astrometric reduction of old photographic plates, benefiting from modern technologies such as sub-micrometric scanners associated with a reduction using accurate catalogues (UCAC at the present time and GAIA in a near future), will improve our knowledge of the dynamics of the Solar System.

In the framework of an international collaboration first, and in the FP7 ESPaCE European project afterward, U.S Naval Observatory plates were digitized with the new generation DAMIAN scanning machine of the Royal Observatory of Belgium. The procedure was applied to a few hundred photographic plates covering the years 1967-1998 of the Galilean satellites, the Martian moons and of the Saturnian satellites. We succeeded in obtaining results with an accuracy better than 70 mas in (RA, Dec) positions of the Galilean moons, and better than 60 mas in (RA, Dec) positions of the Martian satellites that corresponds to the accuracy of the Mariner astrometric space data. We also provide positions of the Saturnian moons.

Since the positions of the planets may be deduced from the observed (RA, Dec) positions of their satellites, we can assess the accuracy of the ephemerides of Jupiter, Mars and Saturn too. We compare the measurements to the last planetary and satellite ephemerides. We also discuss the impact of the instrumentation on the results.

Brief Bio: 

Dr. Robert obtained his Ph. D. from the Paris Observatory in 2011.  Currently, he is a teacher and researcher at the Institut Polytechnique des Sciences AvancĂ©es (IPSA) in Astrometry and Spatial Mechanics as well as an Associate Researcher at the IMCCE/Paris Observatory.  Dr. Robert is also an expert on the lFP7 ESPaCE European project.

 

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