Circumstances for Pluto-Charon mutual events in 1987

Abstract

Circumstances are tabulated for 88 Pluto-Charon mutual events occurring during the 1987 opposition. Charon is predicted to be completely obscured either by Pluto or Pluto's shadow during each passage behind Pluto during this opposition, providing several opportunities to study Pluto uncontaminated by the light of Charon. The duration of these total events is predicted to be from 32 to 79 min. The mutual-event season is now expected to conclude during the 1990 opposition. Two new stars have been selected as comparison stars for events occurring prior to opposition in 1987. Standardization of the primary comparison stars used in 1985 and 1986 has yielded the following magnitudes: B = 12.6044 + or - 0.0015 and V = 11.7956 + or - 0.0017 (1985 Primary); B = 13.1238 + or 0.0008 and V = 12.3885 + or - 0.0014 (1986 Primary).