spacetelescope / spacetelescope/drizzlepac

Drizzlepac/HAP: Check WFPC2 detection thresholds for alignment

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Python
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Description

Issue HLA-1112 was created on JIRA by Jennifer Mack:

Comment from Rick White in team_burgundy:

 

For image hst_5369_qr_wfpc2_wfpc2_u26kqr in the 2023-09-07 test sample, there are about 25 Gaia stars available for matching, but only about 10 of them (mostly saturated) appear in the final segment catalog. 

I wonder whether the detection threshold issues in the WFPC2 catalogs could be the culprit in getting good Gaia alignments.  If the threshold is too shallow (by a lot) then the Gaia stars do not get detected, and as a result the images do not get aligned. 

It would be worthwhile to have a look at this particular visit to see why it does not get aligned to Gaia;  I think the fraction of WFPC2 datasets that do get aligned will be very small if even this one does not succeed.

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Research direction

Start with the linked HLA-1112 issue and the hst_5369_qr_wfpc2_wfpc2_u26kqr image from the 2023-09-07 test sample. Compare the roughly 25 available Gaia stars with the roughly 10 stars in the final segment catalog, investigating whether WFPC2 detection thresholds prevent alignment; done means identifying the cause and documenting the required correction.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
data
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
30/100

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