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The STSDAS strfits FITS reader preserves the multigroup format of an HST image. This format must be retained if you plan to recalibrate your data in -STSDAS.
clThis action will start an IRAF session. Software in IRAF is organized into packages. To load a package, type its name. Once you are in IRAF, load the stsdas and fitsio packages by typing the following commands:
cl> stsdas
st> fitsio
The prompt (such as fi>) shows the first two letters of the most recently loaded package. The fitsio package contains tasks for handling the FITS format files used for HST images. You can use catfits (described on page 2-4) to produce a listing of the contents of your tape, and strfits to read the data onto disk. When you are done working with your data, you may choose to write it back to tape using stwfits.
1.4.2 Mounting the Tape
Mount the tape on your tape drive. Allocate the device within IRAF by typing:
fi> allocate devicewhere device is the IRAF name of the tape drive. If you are not sure how to mount tapes or don't know the IRAF names that match your tape drives, see your local system administrator for help.
fi> set imtype="hhh"Currently strfits will also copy STIS and NICMOS files properly with imtype set to this value.
Then go to the directory in which you want your files to be stored. For example:
fi> cd /nem/data1/hstdata-
For example, to read files 1 through 10 from the data tape on drive mta, type:
fi> strfits mta 1-10 oldirafname=yesThe tape log you received with your tape will tell you the number of each data file. You can also use the catfits task as follows to print a list of all the files on the tape to the screen:
fi> catfits mta 1-999 | pageContact the Archive help desk at archive@stsci.edu if you have trouble reading your tape.
Be sure to set oldirafname and to "yes" or else the tape will not be read correctly and you will not be able to manipulate the data. This step is vital if you plan
to recalibrate your data. (The parameter xdimtogf should be "yes" by default.)
Once your data are written on your disk, you can deallocate your tape drive by typing:
fi> deallocate deviceYou are now ready to work with your HST data files.
Deallocating the drive is important if you want to remain friends with your coworkers. No one else can use the drive until you deallocate it.
stevens@stsci.edu Copyright © 1997, Association of Universities for Research in Astronomy. All rights reserved. Last updated: 11/13/97 16:07:33