Manpage of velsw
Section: User Commands (1)
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velsw - Change the `velocity' axis of an image.
VELSW is a Miriad task which changes the units on the `velocity'
axis. As velocity and frequency are related by a Doppler shift
formula, it is possible to switch an axis between being labelled
in frequency or velocity. VELSW can switch the axis description
between frequency (labelled FREQ-) and velocity, using either
the `radio convention' (labelled VELO-) or `optical convention'
(labelled FELO-) for the formula relating velocity
Assuming that the data were measured with equal frequency
increments, some approximation is involved assigning a velocity
axis increment for the optical convention. In this case,
the increment stored is correct at the reference pixel.
The name of the input image data set. No default.
This determines what the labelling on the `velocity' axis will
be changed to. Possible values are "frequency", "optical" (for
velocity using the optical convention) or "radio" (for velocity
using the radio convention). There is no default.
Optionally you can give a second value to define the rest frame.
This can be "barycentre" (solar system barycentre), "lsr" (Local
Standard of Rest) or "observatory" (topocentric). The default is not
to change this.
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Time: 18:35:39 GMT, July 05, 2011