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, CCD photometry data from fifteen events observed at Palomar Observatory by Buratti and colleagues, and photoelectric photometry data from ten events observed at McDonald Observatory by Young and Binzel.  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). The McDonald Observatory data, taken from Young (1992), includes differential B and V photometry.  Individual lightcurves are included in the subdirectory 'indiv'. These contain the same data as in the full data files. The filenaming system is as follows: obs_yyyymmdd_f.tab, where obs is an abbreviation of the observatory, yyyymmdd is the date of observation, and f is the filter.  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.  In 2008, the data from McDonald Observatory, from Young (1992) and with additional discussion of the data given in Young and Binzel (1993), was added to the data set.  In 2012, the data were broken into individual lightcurves, supplied in a separate subdirectory in addition to the original data files. This change was made to facilitate loading the data into the data Ferret.  References :  Young, E.F., An albedo and frost model of Pluto, Ph.D. thesis, Massachusetts Institute of Technology, 1992. [YOUNG1992]  Young, E.F. and R.P. Binzel, Comparative mapping of Pluto's sub-Charon hemisphere: Three least-squares models based on mutual event lightcurves, Icarus 102, 134-149, 1993. [YOUNG&BINZEL1993]

Confidence Level Overview : 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, Palomar Observatory, and McDonald Observatory. The collection includes both calibrated and uncalibrated data. Additional data will be added in future updates.