[daip] JMFIT reported values

[Eric Greisen]

SUSAN BILL WIDER wrote:
>  
> Eric, DAIP.
>  
>     I was using JMFIT in 31DEC08 AIPS to model a simple 2-d 
> gaussian.   The component is compact, well-defined and has good SNR 
> relative to the background.  In the deconvolution section of the report, 
> the recovered values of the major and minor axes are given in both 
> pixels and arcseconds, and the position angle (PA) in degrees.  However, 
> the PAs accompanying the pixel-scaled values and the astronomical 
> angular values are different, and by significant amounts (e.g 20 degrees 
> in a PA of 131 degrees).  Surely, the deconvolved PA is independent of 
> whatever units I use to report the major and minor axes?  Or have I 
> missed something here?
>  
>                                                                     Bill 
> Junor
> 
>      
The PA in pixels is wrt up in the image.  The PA in coordinate space is 
wrt North.  If you are near the Noth pole these can be quite different 
or if the image is rotated.

ERic Greisen