mscopy -- Copy image sets of a multi-extension FITS file.
mscopy input output
This task copies images. In most situations, imcopy should be used for this purpose. However, mscopy has some features that make it more useful for multi-extension FITS files.
One signficant distinction between mscopy and imcopy is that mscopy copies whole image sets (imsets); it does not copy individual FITS extensions, nor does it copy images of any type other than FITS. The imsets parameter lets you specify which imsets to copy; the default is to copy all of them.
mscopy can copy dummy extensions, ones that consist of just a header, with keywords giving the pixel value and image size (when expanded). Dummy extensions are used in HST data to save space in the FITS file, and they can be present in calibrated as well as raw data. If the input name includes an image section, the coordinate parameters and image size of dummy extensions will be updated as the headers are copied to the output.
In keeping with the idea that mscopy is intended for FITS files in multi-extension (imset) format, the primary header is required to be just a header (no data portion). Keywords INSTRUME and NEXTEND are gotten from the primary header and used to determine the number of extensions per imset and the total number of imsets. If INSTRUME is not found, the number of extensions per imset will be assumed to be three. If NEXTEND is not found, the total number of imsets will be assumed to be one.
As imsets are copied to output, the extension version numbers EXTVER of the output imsets will be explicitly set to consecutive integers. The starting value will be one larger than the EXTVER value in the last image in the output file before copying begins.
One significant feature that imcopy has that mscopy does not is that imcopy allows writing to an image section of an existing output image.
- input [file name template]
- A list of one or more FITS files to be copied.
The file name may include an image section,
in which case that section of each imset to be copied
will be extracted and copied to output.
The file name may NOT include a FITS extension name, version or number (e.g. [sci,2] or ). To copy an individual FITS extension, use imcopy.
- output [file name template]
- Either a directory name or a list of output file names;
in the latter case the number of input and output names must be the same.
Note that the full file name -- including filename extension --
should be specified, unless you have imtype set to "fits".
If the output file does not exist, the primary header of the input file will be copied to create the output file, and the input imsets will then be appended to the output.
If the output file does already exist, the input imsets will be appended.
- (imsets = "-") [string]
- This parameter can be used to list the imsets
which should be copied from input to output.
The default is to copy all imsets.
If input includes more than one file name,
imsets applies to all of the input files.
Type "help ranges" for a description of the syntax.
- (extnames = "SCI,ERR,DQ,SAMP,TIME") [string]
- This is the set of EXTNAME keyword values that make up an imset. Current HST instruments have either three or five extensions per imset. Their names may differ from the default, however, and this parameter lets you specify the names if the ones in the input file do not have the default values. The names in the list must be separated by commas or blanks. If extnames is null or blank, the default set of values will be used. If any names are given, then all those in an imset must be listed; however, more names may be listed (up to five) than there are extensions in an imset.
- (verbose = yes) [boolean]
- Display the names of input and output files as they are copied?
1. Copy the second and third imsets of a.fits, writing the output to a.fits in subdirectory xxx.
ms> mscopy a.fits xxx imsets="2,3"
2. Extract the image section "[20:1043,21:1044]" from every imset of a.fits, writing the output to c.fits. If c.fits does not already exist, the primary header will be created by copying from a.fits.
ms> mscopy a.fits[20:1043,21:1044] c.fits
2. Copy all imsets of both a.fits and b.fits to c.fits.
ms> mscopy a.fits,b.fits c.fits,c.fits
This task was written by Phil Hodge.