DRAGONS: Make preimaging image more legacy compatible

[phirstgemini]

Pre-image recipe / makeIRAFCompatible needs to:

• call applyDQPlabe() to fill in the DQ masked pixels. May need multiple calls to this, to

• • a) fill in isolated pixels like CRs or saturated stars with value from surrounding pixels, and
• • b) fill in all the unilluminated area at the edge of the image with a global median sky value. The latter is what IRAF does and without it, GMMPS autoscale is not helpful.

• remove the VAR and DQ extensions from the output _preimage, because they confuse sextractor in the configuration used in mask making.

[phirstgemini]

Done in 4.x:

[release/4.x 4a520b75c] Fixes for preimaging - update makeIRAFCompatible to put the correct WCS headers in the PHU, and to optionally delete the VAR, DQ and OBJMASK extensions. Update the preimaging recipe to fill in DQ masked pixels and to have makeIRAFCompatible discard the non-iraf-like image planes.

Wait for tests to run then cherry-pick into 4.1.x

[phirstgemini]

Per Email from Kristin 26-Nov, GMOS-N team is good to go. Plan is to sync up with GMOS team and SOSs when return from vacation.

On Wed, Nov 26, 2025 at 11:23 AM Kristin Chiboucas kristin.chiboucas@noirlab.edu wrote:

Hi Paul,

The DRAGONS preimaging came up at the scistaff.  As far as the GMOS team is concerned, I think we are ready to make the switch, but Kathleen pointed out that you were probably using development code that is not available to staff yet and that you might have to do something with the archive as well.  So, just let us know whenever it is ready on your side.  

Cheers,
Kristin