DATA_SET_DESCRIPTION |
Data Set Overview : This data set is intended to include all reported timings of observed asteroid, planet, and planetary satellite occultation events, as well as axes derived from those timings by David W. Dunham and David Herald. Most of these timings are unpublished and have been collected by Dunham and Herald. This version is complete through the end of 2008. The sizes (major and minor axes) derived from the occultation timing data are the result of an analysis program by Dunham and Herald, applied consistently to all the occultation events. Data : The asteroid occultation timing data are collected into two files. The occlist file lists a total of 1417 occultations, one occultation per line, along with the identification of the asteroid and star, and additional information about the star including RA and dec. These lines also include the major and minor axes derived from the timings for that occultation, if any, along with information about the analysis. The list is chronological, with an occultation ID assigned to each one. The occtimings file lists the individual timings measured for each occultation, with one disappearance and reappearance per line, as well as information about the observing site and the observational circumstances. The latitude, longitude, and elevation of each site are included. Two analogous files, occsatlist and occsattime, with occultation data on planets and planetary satellites, are also included. Ancillary Data : Summary files, occsummary.tab and occsatsummary.tab, contain the major and minor axes and position angles from the elliptical or circular fits, extracted from occlist and occsatlist respectively. Graphics image files show plots of the occultation fits for many of the occultations. These image files are located in the document directory, and are accompanied by a descriptive text file 0Graphics.asc explaining how the plots are to be read. The filenames of the image files concatenate the asteroid number, asteroid name or provisional designation, and occultation date. Modification History : The first version of this data set, introduced in 2003, included occultations only through 1998. The update of 2004 not only adds occultations through March 1, 2004, but also provides a more systematic arrangement of the data. The data set was again updated in 2005, 2006, 2007, 2008, and 2009.
|