Astrometric Measurements of Rarely-Observed Minor Planets

Abstract

The 1986 Minor Planet Ephemerides call observers’ attention to the need for astrometric observations of 120 objects on the “critical list”. Their magnitudes are generally between 15 and 18 at opposition. The author’s programme of observation with simple means was described. The equipment used was a Newtonian 41-cm, f/4.8 reflector, a standard camera back, and Kodak TP 2415 film, hypersensitized in forming gas. Out of 25 observations attempted, 20 photographs were obtained, 8 of which were of sufficient quality for the positions to be measured and to be published in Minor Planet Circulars. On two photographs, the minor planet (1982 KM) was detected, but there were no suitable reference stars within the field. (The lack of reference stars brighter than mag. 10 in certain regions should be noted.) The return of measured positions versus photographs obtained (40%) appears very acceptable.