NAME

mMakeHdr - Create a FITS header template for use in mosaic creation

SYNOPSIS

MakeHdr [-d level] [-s statusfile] [-p(ixel-scale) cdelt] [-P maxpixel] [-n] images.tbl template.hdr [system [equinox]]

DESCRIPTION

From a list of images to be mosaicked together, mMakeHdr generates the FITS header that best describes the output image. If the input metadata represent a properly matched set of data cubes (three or four dimensions), the header will reflect this and can be used in cube mosaicking. If the spatial coverage of the data is large enough that a TAN projection header is infeasable, an allsky (AITOFF) header will be created, though this should be used with caution as it can easily be the result of metadata for images that shouldn't really be combined.

OPTIONS

-d level

Turns on debugging to the specified level (1-3).

-s statusfile

Output and errors are written to statusfile instead of to stdout.

-p cdelt

Specify a pixel scale for the header, if different from the input images.

-P maxpixel

Sanity check; forces an upper limit on derived NAXIS1, NAXIS2, just in time.

-n

"North-aligned" flag. By default, the FITS header generated represents the best fit to the images, often resulting in a slight rotation. If you want north to be straight up in your final mosaic, you should use this flag.

ARGUMENTS

images.tbl

Metadata table (generated by mImgtbl) describing the images to be mosaicked.

template.hdr

Path to header template to be generated.

system (optional)

Specifies the system for the header (default is Equatorial). Possible values are:

EQUJ EQUB ECLJ ECLB GAL SGAL

equinox (optional)

If a coordinate system is specified, the equinox can also be given in the form YYYY. Default is J2000.

RESULT

Creation of output file template.hdr.

MESSAGES

OK

[struct stat = "OK", count=nimages, ncube=ncubes, clon=ra, clat=dec, lonsize=crpix1, latsize=crpix2, posang=ang, lon1=ra1, lat1=dec1, lon2=ra2, lat2=dec2, lon3=ra3, lat3=dec3, lon4=ra4, lat4=dec4]

OK

messages about projection and number of axes>

ERROR

Memory allocation failure.

ERROR

Invalid pixel scale string: cdelt

ERROR

Cannot open status file: statusfile

ERROR

Invalid system string. Must be EQUJ|EQUB|ECLJ|ECLB|GAL|SGAL

ERROR

Equinox string is not a number

ERROR

Can't open output header file.

ERROR

Invalid image metadata file: filename

ERROR

Need columns: ctype1 ctype2 nl ns crval1 crval2 crpix1 crpix2 cdelt1 cdelt2 crota2 (equinox optional). Four corners (equatorial) will be used if they exist or even just a single set of coordinates

ERROR

Bad WCS for image n

ERROR

Error computing boundaries.

ERROR

Output wcsinit() failed.

EXAMPLES

$ mMakeHdr 2mass-images.tbl orig.hdr

[struct stat="OK", count=30]

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.

Due to some numerical approximation, the "North Up" bounding box calculated when the -n switch is on can be skewed a fraction of a degree.

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.