The analysis of the HEAO-1 A1, A2, and A4 data products can be done using the XANADU and FTOOLS suite of programs. There are also tasks available to extract lightcurves from the A2 raw data files. There are no software available at the HEASARC to analyze the HEAO-1 A3 raw data. Public domain software can be used to view GIF files (e.g. xv on UNIX or via the Netscape browser on any system).
General FITS file manipulation: The FTOOLS package, futils, provides a suite of programs that can be used to view and manipulate any of the HEAO-1 FITS files. To view the data particularly useful are the tasks fplot (to plot the data), fdump (to dump the data file content), fstruct and flcol (to get the structure and column name of the FITS files). Basic selection and column manipulation can be done using fselect (to select rows based on the result of a boolean expression), fcalc (to calculate values for new column based on arithmetic expression) and fstatistic (to compute standard statistical value on a column). Alternatively most of the operations (and more) mention above can be done using fv, the interactive FITS file viewer and editor.
Spectra and Lightcurves :
Spectra and lightcurves can be analyzed using
Xspec is a general spectral fitting programs, providing a number of already
made standard models. To use XSPEC with the HEAO-1 A2 & A4 archive files,
it is necessary to extract from the archive a source and background
spectrum and a response matrix.
Note: The area in the file refer to the nominal on-axis area of the detector and the spectra have not been corrected for the reduction in the collimator efficiency during the period when the source was observed off-axis. Therefore the count rate and the normalization in the spectral fitting maybe be incorrect.
A2 Raw rates files : To extract a lightcurve or a scan profile from the HEAO-1 raw rate and scanning data, three programs are available : a2source, a2lcurve, and dsdlcurve. These programs are part of the HEAO-1 package distributed with the FTOOLS. A2source and a2lcurve operate on the A2 raw rate data and dsdlcurve operates on the DSDISK data. No software is available for the LED detectors.