Astrometry of the inner Jovian moons Thebe, Amalthea, and Metis

Abstract

The paper presents the results of the astrometric observations of the inner Jovian satellites Thebe, Amalthea, and Metis obtained with 2-m Zeiss RCC Telescope located at Peak Terskol Observatory. The 268 inter-satellite positions were gathered during the five-year period between 1998 and 2002. Comparison of the observed positions with those of JPL JUP203 ephemerides demonstrates high quality of the collected observations. The RMS errors of the differences between the observed and the theoretical positions are about 0.10, 0.15, and 0.30 arcsec for Amalthea, Thebe, and Metis, respectively. Thebe and Amalthea's mean residuals are about zero. The dispertion of the mean residuals derived from the data sets obtained in the different years does not exceed 0.04 arcsec. The brief description of the technique for the scattered light subtraction may be useful as an experience of the image processing of a faint object near the bright planet.