CCD Positions for the Outer Planets in 1995 Determined in the Extragalactic Reference Frame
Abstract
This paper presents positions for the planets Uranus, Neptune, and Pluto in 1995 determined in the extragalactic reference system with the Flagstaff CCD transit telescope (Stone et al. 1996, Al, 111, 1721). In this paper, these positions are compared with the recent DE403 planetary ephemerides discussed in Standish et al. [1995, JPL IOM 314.10-127 (DE403).] There is excellent agreement between the observed and predicted positions for Uranus and Neptune, wherein no evidence for systematic errors is found, and the mean (Observed-DE403) differences in position are small (≤0.06 arcsec in magnitude) and not significantly larger than their formal errors. The scatter in the residuals for these planets is J 0.24 arcsec in both coordinates, which can be explained by observational errors. For Pluto, the agreement is very good, but there is marginal evidence for an offset (Observed-DE403) in declination amounting to 0.13±0.03 (s.e.) arcsec. This possibility is based on only 22 observations, and clearly, future observations are needed for clarification. The scatter in the Pluto residuals is σ±0.15 arcsec in both coordinates, which is very small when compared with other Pluto observations.
- Publication:
-
The Astronomical Journal
- Pub Date:
- August 1996
- DOI:
- 10.1086/118053
- Bibcode:
- 1996AJ....112..781S
- Keywords:
-
- EPHEMERIDES;
- PLANETS AND SATELLITES: GENERAL