[daip] Re: Help comparing images in different equinoxes

[Eric Greisen]

Eric Perlman writes:

 > I am trying to compare images taken with different equinoxes (one in B1950, 
 > one in J2000), and I believe I am running into problems with the rotation of 
 > the north-south line that goes along with precession.  Is there a task in 
 > AIPS that precesses images and corrects for this rotation?  I cannot find 
 > information about this in the HELP or EXPLAIN files for OHGEO or HGEOM.
 > 

Precession is rather complex and we do not regrid images to switch the
two epochs.  The verb EPOSWTCH will switch the header.  You may then
undo the rotation that will appear in the header with LGEOM or OGEOM.

Eric Greisen