PUNCH_IDL_Tools

Tools for accessing PUNCH data in IDL and/or GDL.

These tools require the gen and astrom packages from SolarSoft.

The intent is that they will allow SolarSoft users to ingest and interpret any level of PUNCH data from Level 0 to 3.

They should work equally well in recent versions of IDL and the current GIT of GDL.

Status

These routines have as yet had limited testing. In particular, as yet no images with non-null distortion tables have been available for testing.

Tools provided.

READ_PUNCH:

Reads a PUNCH FITS file into IDL. This should handle the Rice-compressed files either with the shared library and fitsio_read_image or via the imcopy command, and the regular readfits procedure.

N.B. The layout of a Rice-compressed file is assumed to be:

• A dummy header for the primary data block.
• The actual primary data compressed into a BINTABLE in the first extension.
• Uncertainty information in the second extension.
• Distortion lookup tables in the third and fourth extensions.

PUNCH_STACK

Reads the data from a list of PUNCH FITS files into a data cube. Also returns supporting data (uncertainties and distortions) as available.

PUNCH_XY2AD and PUNCH_AD2XY

In the current SolarSoft astrometry package, the only way to access distortion tables is by opening the file with fits_open, but this is not possible for RIce-compressed files. These routines therefore combine the relevant parts of fits_xy2ad and xy2ad, and fits_ad2xy and ad2xy respectively.

PUNCH_WCS_GET_COORD and PUNCH_WCS_GET_PIXEL

These allow the use of distortion tables alongside the WCS family of SSWIDL astrometry codes.

FIX_Z_HEAD

Modifies header keys starting with "Z", in Rice-compressed files read by fitsio_read_image to be the actual image parameters (e.g. ZNAXIS1 becomes NAXIS1), tries to follow the pattern of imcopy. This is only intended to be used internally within read_punch.

Getting help

All routines contain a documentation header that can be read via doc_library.

For further assistance, please open an issue or create a discussion here on GitHub.

Note that at present the distortion tables are not tested as we do not yet have data with non-null tables.

Contributing

We welcome all contributions. Please open a pull request to contribute.

imcopy

is an anciliary program that is part of the cfitsio library. However many Linux distributions do not build it by default. It can be simply built by downloading the cfitsio source and going to the utilities subdirectory and compiling with (assuming the cfitsio library is installed):

gcc -o imcopy imcopy.c $(pkg-config -libs -cflags cfitsio$)

and copying the executable to somewhere in your path (e.g. ~/bin).