Construct an NDF holding the weights array for a particular chop throw and the Fourier
Transform (FT) of the chop function (a sine wave).
CHOP = REAL (Read)
Chop throw in arcseconds. There is
no default
FTCHOP = NDF (Write)
Output NDF containing fourier transform of the
chop function. The size of the output array matches the dimensions supplied by parameter
SIZE
LIKE = NDF (Read)
This parameter may be used to supply an NDF which is to be
used as a template. If such a template is supplied, then its origin (its lower pixel-index
bounds) and extent will be read used for the output NDFs. By default no template will be
used and the size information will be read from the SIZE parameter. Additionally, the PA,
PIXSIZE and CHOP parameters are searched for in the FITS extension if one is present
(using keywords of CHOP_PA, SCUPIXSZ and CHOP_THR respectively). These parameters
values are requested if not found in the FITS extension.
MSG_FILTER = CHAR (Read)
Message filter level. Default is NORM.
OUTCHOP = REAL (Write)
Chop throw angle
actually used.
OUTPA = REAL (Write)
Position angle actually used.
OUTPIXSZ = REAL
(Write)
Actual pixel size used (arcsec)
PA = REAL (Read)
Position angle of chop throw.
Positive is anti-clockwise starting from North. The angle should be specified in degrees.
PIXSIZE = REAL (Read)
Pixel size to be used for output images. Should be in arcseconds
(ie same units as used for the CHOP parameter)
SIZE( 2 ) = INTEGER (Read)
Array
parameter containing the number of pixels (X, Y) in the output images.
WTCHOP = NDF
(Write)
Output NDF containing the weights contributed by this chop configuration. This is
FTCHOP squared. The size of the output array matches the dimensions supplied by parameter
SIZE