Manpage of linmos
Section: User Commands (1)
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linmos - Linear mosaicing of datacubes
LINMOS is a MIRIAD task that performs simple linear mosaicing
of input cubes to produce a single output cube. If only one
input cube is given, LINMOS essentially does primary beam
correction on it. If the input cubes overlap, LINMOS combines
the overlapping regions so as to minimize the rms error.
To determine the primary beam of the telescope, LINMOS first
checks the map header for the presence of the "pbtype" and then
"pbfwhm" parameters. If present, LINMOS assumes the primary
beam is the given type. If these parameters are missing, LINMOS
checks if the telescope is one that it knows. If so, then the
known form for the primary beam is used. See task "pbplot" to
check LINMOS's primary beam models.
The names of the input cubes - many may be given. There is no
default. Inputs should generally be on the same grid system.
If not, linear interpolation is performed to regrid using the
first image as the template. LINMOS's ability to do this is
inferior to task REGRID. The intensity units of all the inputs,
and the pixel size and alignment of the third dimension are
assumed to be the same.
The name of the output cube. No default. The center and pixel
size of the first input image is used as the grid system of the
RMS noise level in each of the input cubes. If not specified,
the value is taken from the 'rms' item in the input image header
if that is available, and if not, then the rms of the previous
image is used. If no value could be determined for the first
image, a warning is issued and ALL images are given equal weight
by assigning an RMS of 1.0.
Bandwidth of the image in GHz. If specified the beam response
will be averaged across the frequency band before
being applied to the image. Use for wide band images to
improve the accuracy of the correction.
Extra processing options. Several can be given, separated by
commas. Minimum match is supported. Possible values are:
taper By default, LINMOS fully corrects for primary
beam attenutation. This can cause excessive
noise amplification at the edge of the mosaiced
field. The `taper' option aims at achieving
approximately uniform noise across the image.
This prevents full primary beam correction at the
edge of the mosaic. See Eq. (2) in Sault,
Staveley-Smith and Brouw (1996), A&AS, 120, 375,
or use "options=gains" to see the form of the
sensitivity Rather than a mosaiced image, produce an image
giving the RMS noise across the field. This is
dependent on the RMS specified, either as an
input parameter or else as a header item (see
gain Rather than a mosaiced image, produce an image
giving the effective gain across the field. If
options=taper is used, this will be a smooth
function. Otherwise it will be 1 or 0 (blanked).
nmos.for,v 1.3 2011/06/10 12:03:56 pteuben Exp $
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Time: 18:35:38 GMT, July 05, 2011