[daip] aips_gripe

[David Hogg]

{29-APR-2002 12:55:05}
{circe        UN-REGISTERED!!!!!!!}
{  337  31DEC02  LINX}
{david hogg}
{NRAO,520 Edgemont Road, Charlottesville, VA 2229}
{(434)-296-0256}
{This is in the nature of a comment, rather than a gripe.
 I do not see what is the best way to get a moment map of HI corrected
 for the primary beam. It does not seem possible to apply PBCOR to
 a MOMNT MOM0 map. I could BLNK each channel, SQASH the cube, and
 PBCOR that result. I note in passing that PBCOR works only if you
 squash a 'FREQUENCY' map, whereas the usual total intensity map
 is in velocity units, but one can fix that in the caption. More
 serious is that one still must run MOMNT to get the velocity field.
 Altenatively I could apply PBCOR to each channel and run MOMNT, but
 (it seems to me) that the flux cutoff is a function of position in the map,
 and MOMNT can't handle that.
 I believe that applying PBCOR to a MOMNT map is inaccurate in detail,
 since different parts of the map come from different velocities and
 therefore require a slightly different beam correction. But in my case
 the bandwidth is 1 or 2 MHz in 1420 MHz, and I would be willing to live
 with that approximation.
 What is your thinking on this issue. Have you deliberately avoided
 the capability of applying PBCOR to MOMNT MOM0 maps for technical
 reasons, or is it simply a task that could be done but has low
 priority.
 (please excuse the typos -- I haven't figured out how to fix them).
  }
{The way to apply PBCOR to an HI moment map}
{dhogg at nrao.edu}
{ }