The UT date is required so that the names of the raw data files can be derived via observation numbers. The -ut option can be used to specify the UT date of interest. For example,
% oracdr -ut 19980715
Currently, the pipeline can only process data from a single UT date in any single invocation. Data from multiple nights can not be coadded (even if they are in the same directory since the filename is derived from the UT)3.
In general, the oracdr_scuba can be used to configure the UT date so that the -ut flag will not be required. Rerun oracdr_scuba when data from a different UT date are to be reduced.
ORAC-DR -- SCUBA Pipeline Data Reduction