MSUBIMAGE

NAME

mSubimage - Create a "cutout" of a FITS image

SYNOPSIS

mSubimage [-d] [-a] [-h hdu] [-s statusfile] in.fits out.fits ra dec xsize [ysize]

mSubimage -p [-d] [-h hdu] [-s statusfile] in.fits out.fits xstartpix ystartpix xpixsize [ypixsize]

DESCRIPTION

Creates a subimage (or "cutout") of a FITS file. Note that in "normal" mode, all the parameters (location and size) are in degrees; in pixel (-p) mode, all of them are in pixels

OPTIONS

	-d		Turns on debugging.
	-a		All pixels - Force retrieval of whole image (useful to extract an entire HDU)

-h hdu

Operate on the specified FITS header extension (HDU)

-s statusfile

Output and errors are sent to statusfile instead of to stdout

-p

Pixel mode - create subimage using pixel locations, instead of a location on the sky

ARGUMENTS

in.fits

Input FITS file.

out.fits

Path to output FITS file.

	ra		In normal mode, RA of center of output image.
	dec		In normal mode, declination of center of output image.

xstartpix

In pixel mode, pixel along the x-axis where the cutout image will begin

ystartpix

In pixel mode, pixel along the y-axis where the cutout image will begin

	xsize		In normal mode, width of output image in degrees.
	ysize		In normal mode, height of output image in degrees (default is equal to xsize.

xpixsize

In pixel mode, width of output image in pixels

ypixsize

In pixel mode, height of output image in pixels (default is equal to xpixsize

RESULT

[struct stat="OK", content="blank, flat or normal"]

The content keyword indicates whether all pixels where NaN (blank), all pixels were the same value (flat), or the image appears to be normal.

MESSAGES

	OK		[struct stat="OK", content="blank, flat or normal"]
	ERROR		HDU value (hdu) must be a non-negative integer
	ERROR		Cannot open status file: statusfile
	ERROR		Center RA string (string) cannot be interpreted as a real number
	ERROR		Center Dec string (string) cannot be interpreted as a real number
	ERROR		X size string (string) cannot be interpreted as a real number
	ERROR		Y size string (string) cannot be interpreted as a real number
	ERROR		Invalid ’x’ size
	ERROR		Invalid ’y’ size
	ERROR		Image file filename missing or invalid FITS
	ERROR		Cannot find HDU hdu
	ERROR		Output wcsinit() failed.
	ERROR		Location is off image
	ERROR		Region outside image
	ERROR		No pixels match area.
	ERROR		Can’t create output file: out.fits
	ERROR		FITS library error

EXAMPLES

$ mSubimage image1.fits subimage.fits 307.9 37.29 .01 .01

[struct stat="OK", content="normal"]

BUGS

The drizzle algorithm has been implemented but has not been tested in this release.

If a header template contains carriage returns (i.e., created/modified on a Windows machine), the cfitsio library will be unable to read it properly, resulting in the error: [struct stat="ERROR", status=207, msg="illegal character in keyword"]

It is best for the background correction algorithms if the area described in the header template completely encloses all of the input images in their entirety. If parts of input images are "chopped off" by the header template, the background correction will be affected. We recommend you use an expanded header for the reprojection and background modeling steps, returning to the originally desired header size for the final coaddition. The default background matching assumes that there are no non-linear background variations in the individual images (and therefore in the overlap differences). If there is any uncertainty in this regard, it is safer to turn on the "level only" background matching (the "-l" flag in mBgModel.

COPYRIGHT

2001-2015 California Institute of Technology, Pasadena, California

If your research uses Montage, please include the following acknowledgement: "This research made use of Montage. It is funded by the National Science Foundation under Grant Number ACI-1440620, and was previously funded by the National Aeronautics and Space Administration’s Earth Science Technology Office, Computation Technologies Project, under Cooperative Agreement Number NCC5-626 between NASA and the California Institute of Technology."

The Montage distribution includes an adaptation of the MOPEX algorithm developed at the Spitzer Science Center.