[daip] Velocity conversion

[Eric Greisen]

Flor Allaert wrote:
> Hi,
> 
> I'm analysing HI data from several galaxies and the observations were  
> performed at different telescopes. I'm trying to convert all the  
> velocities to 'RADIO wrt SUN' using AIPS, but I'm not quite sure how  
> to do this. Should I use ALTDEF? And if so, should I manually  
> calculate the velocity at the reference pixel?

AIPS does not have DOPSET capabilities and so depends on the telescope 
or the user to provide them.  I would suggest optical wrt Sun which is 
more commonly used.  I think that is what the VLA did back when we 
tracked velocities.

ALTDEF is for letting the user provide the information and you may have 
to compute it.

Eric Greisen