16.4 Converting XAS files to/from plain FITS files

All kinds of XAS files can be converted one-to-one to plain FITS files (in the form either of FITS images or FITS binary tables). This provides an effective way of importing XAS data into any astronomical package. The burden of converting to the conventions used in the target package (e.g. column names or order, keyword names) is left to the user.

Conversely a plain FITS file (FITS image, single-extension FITS binary table) can be converted into a XAS file. This is assumed mainly to re-import files manipulated in other packages.

See elsewhere for conversions using OGIP conventions.

There are three commands to handle XAS <--> FITS conversion :

conversion from XAS to FITS
```
tofits [file 
```
converts a XAS file (the filetype part of the name may be omitted if it can be derived from the context) into a FITS file. The name of the output file is obtained replacing the filetype dot with an underscore and adding a .fits extension (thus e.g. pinco.image gives origin to pinco_image.fits.
XAS image files (images, pseudoimages and response matrices) are converted to FITS images, all other files to FITS binary tables.
It is care of the user to rename the file if so is required by the target package.
conversion from FITS to XAS
```
fromfits [fitsfile logflag commentflag
```
converts a FITS file (whose name MUST include any filetype extension) into a XAS file. The name of the output file is derived "inverting" the naming convention used by tofits, if at all possible, otherwise it will do its best to assign a XAS file type (e.g. pinco_image.fits recreates pinco.image, but an image with name pinco_panco.fits creates pinco_panco.image)
finalising the conversion from FITS to XAS
It is possible that fromfits does not recognise the content of a tabular FITS file, and therefore names it using a .generic extension, and flagging it as a generic XAS table. Of course renaming is always possible, but it may be desirable to flag the file as one of the standard XAS types (if its content is compatible). This is achieved with
```
degeneralize [file xastype 
```

Beware that the conversion from/to FITS is handled using the FITSIO library, and therefore it uses that library's error conventions (in particular an existing FITS file is never overwritten, contrary to XAS usage) and codes.

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sax.iasf-milano.inaf.it/Xashelp/export.4.html :: original creation 2002 Sep 04 18:09:45 CEST :: last edit 2002 Sep 04 18:09:45 CEST

16.4 Converting XAS files to/from plain FITS files

conversion from XAS to FITS

conversion from FITS to XAS

finalising the conversion from FITS to XAS

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