SPECSHIFT shifts all spectra in a cube according to a 2-D template
(a velocity field). The velocity of the template is made the
central pixel of the spectrum. If the template is blanked or out
of range the spectrum is unchanged. Based on Bart Wakker's HANNING.
The input data cube. vxy and xyv images are acceptable inputs.
The region of the input cube to modify. By default the whole
cube is processed.
The template image, should be 2-D with same RA/DEC axes as the
The velocity pixel which will be assigned to the template
velocity. Default is the middle pixel of the v-range.
doblank Don't wrap profile around; blank if out of range.
By default the edge channels are assumed to be noise
so the profile is wrapped when shifting beyond edges.