This script allows users to download part of the Chandra CALDB that pertains to their specific OBS_ID.

This can result in significant saving in disk space and bandwidth as only a small fraction of the CALDB files are needed for individual observations.

Users can setup their local CALDB to accumulate files from multiple observations, in which case the duplicate files can be skipped.

The CALDB tree can be localized together with the science data products providing a complete, versioned set of files required to duplicate the analysis.

% download_chandra_obsid 635
% download_obsid_caldb 635 635/CALDB
% export CALDB=635/CALDB
% export CALDBCONFIG=635/CALDB/config/CHANDRA-4.6.7.config
% chandra_repro 635 635/repro