The AAVSO is happy to provide a copy of Bob Nelson's O-C files for Eclipsing Binaries for 2012. These files can be used for observation planning, and are a valuable resource for EB observers.
Thanks once again for Bob Nelson for providing this service to the EB community.
Nelson Database of Eclipsing Binary O-C Files
Bob Nelson has developed over 5400 O-C (Observed - Computed) files of eclipsing binaries, all in Excel format, that we are hosting on our site. The purpose is to provide information on period variation for selected eclipsing binaries (for astronomers interested in a particular star) and to determine the best elements for predicting future eclipses.
The AAVSO now distributes its published times-of-minimum data for eclipsing binary in single compressed files (.tgz and .zip), rather than as a searchable online index. For data on a specific star, unzip the compressed file, and search for the star's name among the included text files. These files contain updated publication information through November 30, 2005, the time at which the files were last updated.