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Keep per-epoch exposure and CCD identity in the final catalog

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#890 0 comments 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
78/100
Issue type
Feature
Clarity
Clearly specified
Activity status
Active
Tech stack
python

Research direction

Start with the key handling in src/shapepipe/modules/ngmix_package/ngmix.py:1171-1174 and the catalog-writing logic at src/shapepipe/modules/make_cat_package/make_cat.py:602. Preserve the per-epoch exposure ID and CCD number in the final catalog as EXP_ID_n and CCD_n alongside the existing HSM_*_PSF_n columns, then verify each epoch slot retains the expected identity.

Written by the indexing model from the issue text.

Description

The final catalog records how many exposures went into each galaxy's fit (N_EPOCH, NGMIX_N_EPOCH) but not which ones. make_cat.py writes the per-epoch PSF columns by enumeration index and drops the exp_name-ccd_n key that ngmix.py has at fit time, so no CCD, exposure-epoch, or dither-phase split of the shear catalog is possible without rerunning shape measurement.

The Paper II referee asked for exactly such a split of the B-mode null tests; we replied that this information will be recorded for the tomographic catalog.

Add per-epoch exposure ID and CCD number columns — EXP_ID_n, CCD_n for each epoch slot, in the same layout as the existing HSM_*_PSF_n columns — so the catalog supports these splits.

Pointers: src/shapepipe/modules/ngmix_package/ngmix.py:1171-1174 (key available), src/shapepipe/modules/make_cat_package/make_cat.py:602 (key discarded).

Dominant language
Python
Stars
18
Forks
14
Avg merge
8h 40m
Merged PRs (30d)
10

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