0000000000328792
AUTHOR
A. Ortiz Gil
Orbit determination and errors of a star catalogue
Abstract We obtain Ceres orbit taking into account all perturbations and applying correction of phase effect to observations. More than 3000 observations have been used and the results agree with other determinations. We have also investigated the influence of systematic errors of a star catalogue on the observations and its effect on final elements. To that aim, a simulation procedure has been applied to Ceres observations, including different laws for errors of star catalogue versus spherical coordinates. The best relations have been applied to real observations of Ceres, in order to obtain elements and star catalogue corrections. Preliminary results of these calculations are presented.
Star Image Identification and Characterization on Astrographic Plates
The automatic identification and characterization of star images has great value for the preliminary analysis and measurement of astrographic plates. Our group at Valencia Observatory is using a small 2-D stage and a CCD camera under computer control to perform systematic measurements of bright asteroid plates. We are also applying this method to the processing of astrographic plates with crowded stellar fields and non-stellar objects in collaboration with the Pulkovo Observatory.
HST observation of the inner coma of 2060 chiron
Abstract The analysis of persistent comae of very large and distant comets allows us to infer the poorly known physical properties of dust and icy grains produced beyond Jupiter. Chiron is particularly interesting because Fulle ( Astron. Astrophys. 282 , 980–988; 1994) has shown that the strong asymmetricity of its coma (West, Astron. Astrophys. 241 , 635–645 1991) allows us to infer rotational properties of Chiron's nucleus. In this paper we report the observation of the asymmetric inner coma of Chiron from the analysis of 44 images of Chiron and eight images of a standard star available from the HST archive. The images were taken during February/March 1993, when Ch iron was 9.3 AU from th…