[daip] New Staff Reply - [!UXJ-401994]: FITS new WCS problem

[Eric Greisen]

New Staff Reply: FITS new WCS problem

A MNJ tomorrow will improve the situation for you.

The issue is that both the diagonal terms and the off
diagonal terms can give the axis increments and the
printed error messages show the two separate computations.
IRAF is doing a general fit and gets cross terms about 1/1000
of the diagonal terms.  AIPS was taking those small numbers
seriously - the FITS file gives many digits.  I have changed it
the average the on and off diagonal solutions only if the
rotation angle is between about 6 and 84 degrees and to use
the primary solution otherwise.  I also changed it to prefer
rotations less than 90 degrees, rather than the 179 degrees
found directly.

Cheers

Eric Greisen


Ticket Details
===================
Ticket ID: UXJ-401994
Department: AIPS Data Processing
Priority: Default
Status: Closed
Link:  https://help.nrao.edu/staff/index.php?_m=tickets&_a=viewticket&ticketid=2203