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THE .IRAF FILE AND CCD HEADER INFORMATION

The .iraf file is currently used to inform iraf of which spectrum corresponds to which object. The slit position is indicated by the first column of the file. The second is a flag used by IRAF to determine the type of spectrum (-1 for unused, 0 for sky, 1 for object, and 3 for random position). The third column gives the object name and references the user id number for that object (in parentheses). The decision to leave out any currently unused fibers that were used in a previous configuration causes those entries in the file to be labeled as ``Random position". They may either be used as additional skies or ignored during the data reduction process.

In the near future, iraf will no longer need the .iraf file for the object to spectrum cross-referencing as the pertinent information is now being stored into the CCD headers. The .iraf files will, however, continue to be used as a backup in case the information in the headers becomes corrupt or is missing.





Sam Barden
Tue Aug 29 16:45:05 MST 1995