Data Set Overview : During the period 1985-1990, the earth entered the orbital plane of Pluto and its moon Charon, and the mutual eclipse events were observed from ground-based observatories. A subset of these data are included in this data set, and more will be added in future updates. The current version contains photoelectric photometry data from thirty-nine events observed at Mauna Kea Observatory by Tholen, and CCD photometry data from fifteen events observed at Palomar Observatory by Buratti and colleagues.  Data : The Mauna Kea data is in the file pcmemko.tab, and includes standard B magnitudes and errors, and Julian date at mid- observation, corrected for light-travel time. The Palomar data is in the file pcmepal.tab, and includes differential magnitudes and errors, and Julian date at mid-observation (uncorrected).  Modification History : In January 2002 SBN personnel calculated UTC based on the Julian dates provided and added it to the data files. At the time resolution of the Julian date (less than 1.e-05), UTC and UT are equivalent. START_TIME and STOP_TIME values were updated throughout as appropriate. No other data values were changed.

Review : This version of the data set underwent formal external review on May 10, 2002.  Data Coverage and Quality : The data set is eventually intended to be a complete collection of groundbased observations of the Pluto-Charon mutual events. At present, it contains visual photometric data from Mauna Kea Observatory and Palomar Observatory. Additional data will be added in future updates.