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Dynamical reference frames in the planetary and earth-moon systemsEstimates of the accuracies of the ephemerides are reviewed using data for planetary and lunar systems to determine the efficacy of the inherent dynamical reference frame. The varied observational data are listed and given with special attention given to ephemeris improvements. The importance of ranging data is discussed with respect to the inner four planets and the moon, and the discrepancy of 1 arcsec/century between mean motions determined by optical observations versus ranging data is addressed. The Viking mission data provide inertial mean motions for the earth and Mars of 0.003 arcsec/century which will deteriorate to 0.01 arcsec after about 10 years. Uncertainties for other planets and the moon are found to correspond to approximately the same level of degradation. In general the data measurements and error estimates are improving the ephemerides, although refitting the data cannot account for changes in mean motion.
Document ID
19910070140
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Standish, E. M.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Williams, G.
(JPL Pasadena, CA, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1990
Subject Category
Astronomy
Meeting Information
Meeting: Symposium of the IAU
Location: Leningrad
Country: USSR
Start Date: October 17, 1989
End Date: October 21, 1989
Accession Number
91A54763
Distribution Limits
Public
Copyright
Other

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