CCD astrometric observations of Amalthea and Thebe
Observatório Nacional, Rua General José Cristino 77, 20921-400 Rio de Janeiro, Brazil e-mail: email@example.com
2 Observatório do Valongo, Ladeira Pedro Antônio 43, 20080-090 Rio de Janeiro, Brazil
3 Institut de Mécanique Céleste et de Calcul des Éphémérides, 77 avenue Denfert Rochereau, 75014 Paris, France
Accepted: 14 March 2005
This paper presents the results of observations of Jupiter's satellites Amalthea and Thebe made in 1995, 1996 and 2001 at the Laboratório Nacional de Astrofísica (LNA), Brazil. The observations were made in visible light wavelengths with a 1.6 m reflector telescope and the light of Jupiter was covered by a mask placed near the CCD surface. The already published positions for 1995, whose astrometric reduction used the Galilean satellites, are now reduced using the stars in the CCD fields like the new positions of 1996 and 2001. The 2001 data are much better than those obtained in 1995, and that those from 1996 show large residuals. Considering the 310 frames observed, the mean residual is about 001 and the standard deviation is about 015.
Key words: astrometry / Jupiter satellites / Amalthea and Thebe
© ESO, 2005