3.2 How to input Data

 

     

The following describes the standard procedure:

• For each dataset you should first create a new directory to store the data, because the resulting data file names are usually unique only within one observation. If you want to store several datasets in one directory, the INTAPE/... commands allow optionally also a different naming structure.
• Next move to the new directory and start your EXSAS session there.
• Within EXSAS use one of the commands INTAPE/RDF, INTAPE/ROD   or INTAPE/USROD, depending on the specific FITS structure of your data. These procedures expect a data tape (cassette) on a reader, or the FITS files on disk. FITS data sets are read and converted to MIDAS/EXSAS tables and images. Finally these tables and images are renamed to their standard names.
• The set of files on a data tape contain in some cases also calibration tables and matrices, which usually reside already in the EXSAS Calibration Area of your EXSAS installation and are automatically retrieved from there. You might therefore wish to delete these files in your observation directory to save disk space. This can be performed optionally by the INTAPE/... command.

If you have to copy the FITS files over the network be sure not to swap bytes during that process (e.g. use the binary mode on ftp, or for the DECNET transfer from VMS to UNIX use the `dcp -i' command option).