The ASCAMASTER table contains data on all ASCA observations that were ever in any of the following states: 'Accepted', 'Scheduled Long-Term', 'Scheduled Short-Term', 'Processed', and 'Archived'. The final status of an observation is given by the parameter Status. Specific dates that affect the status of an observation are listed as the parameters scheduled_date, observed_date, processed_date, archived_date, and cycle. Notice that, if one or more of the date parameters are empty for a given observation, this means that that those particular processes have not occurred: e.g., if observed_date is empty, this means that the planned observation was not observed. This is a service provided by NASA HEASARC .