Content-type: text/html Manpage of velsw

velsw

Section: User Commands (1)
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NAME

velsw - Change the `velocity' axis of an image.  

PERSON RESPONSIBLE

rjs  

CATEGORIES

map manipulation  

DESCRIPTION

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 and frequency.

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.  

PARAMETERS

in
The name of the input image data set. No default.
axis
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.


 

Index

NAME
PERSON RESPONSIBLE
CATEGORIES
DESCRIPTION
PARAMETERS

This document was created by man2html, using the manual pages.
Time: 18:35:39 GMT, July 05, 2011