Producing CALDB Data Files

To produce your own calibration files in a CALDB-type format

Just follow these steps:
  1. If your calibration data file is not in FITS format, convert the to FITS format. This may be the trickiest step since you'll probably have to access or write software to read your file format and to generate the FITS formatted output. The utility fcreate (part of the FTOOLS software package) allows you to create FITS files based on ASCII templates, which may be helpful. You'll need to decide how to arrange your information within the FITS file (separate extensions, tables vs. images, etc.)

  2. Add the CALDB-required set of header keywords. You should try to use keyword values which have been previously defined, if possible. A note on case sensitivity for FITS CALDB keyword values:

    • the CALDB is CASE-InSenSItiVe. You can use upper-case, lower-case, or mixed case strings for values of the TELESCOP, INSTRUME, DETNAM, etc keywords. However, these values will be converted to upper-case when indexed by the CALDB software.

  3. Verify your data file to make sure it's a valid FITS file (one way is to use the fverify routine available in the FTOOLS software package)

  4. Verify the checksum of your data to ensure that the CHECKSUM and DATASUM keywords as used are valid. Use of the CHECKSUM and DATASUM keywords are highly recommended to ensure data integrity. The FTOOLS utility fchecksum will verify, update and/or create the CHECKSUM & DATASUM keyword values.

  5. If you want to install this file as part of your local CALDB
    1. Populate the appropriate sub-directories with your new local/personal calibration files
      (i.e. $CALDB/data/< mission >/< instrument >/responses/my_own_response.rmf)
    2. Index your cal files in the caldb.indx (i.e. $CALDB/data/< mission >/< instrument >/caldb.indx} by
      1. cd to the directory which contains the calibration file (for example, $CALDB/data/< mission >/< instrument >/responses)
      2. run the FTOOL udcif. UDCIF will require the calibration filename, the name (and location) of the index file, and the "quality value" of dataset being entered (a quality value of 0 means 'good' quality).
    3. Run the FTOOL caldbflag to flag the new calibration file as "LOCAL" in the CAL_ORIGIN column of the caldb.indxfile).
    4. Perform an fdump on the caldb.indx to check the files have been indexed correctly

  6. If you want to have this file, or set of files, included in the standard HEASARC CALDB, please contact

Additional Information

  • As an example see this ASCII dump of the headers for one of the ROSAT Position Sensitive Proportional Counter Detector Maps Currently archived in the CALDB.

  • Also take a look at this dump of the Calibration Index File for the ROSAT Position Sensitive Proportional Counter.

Page author: Michael F. Corcoran
Last updated: Wednesday, 20-Oct-2021 10:38:22 EDT.