DM-37058: Disable unnecessary measurements in CCD forced photometry #244
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| @@ -252,10 +250,21 @@ class ForcedPhotCcdConfig(pipeBase.PipelineTaskConfig, | |||
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| def setDefaults(self): | |||
| # Docstring inherited. | |||
| super().setDefaults() | |||
| # TODO: Why not this one? | |||
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A bare TODO? Maybe it needs a noqa? 😄
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Ah, right: this was an open question. The original ForcedPhotCcdConfig here doesn't set doReplaceWithNoise=False but ForcedPhotCcdFromDataFrameConfig does. What's the rationale for them being different? I added it here because the "fromDataFrame" code is newer, and this seems like something we wouldn't want for forced photometry anyway. Thoughts?
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You need heavy footprints from a deblender for replaceWithNoise=True, and you can't get those from a dataframe at all.
You can't really get them from an afw.table.SourceCatalog in CCD forced phot, either, because the ones you've got are for the wrong coordinate system and PSF. But I think there was some code path that downgraded the heavy footprints to regular ones as it transformed them, and I think if given those replaceWithNoise=True will just use them to replace other parent footprints with noise, not blended neighbors, which is of course much less useful.
So this is a story of the afw.table version making sort of a feeble attempt at handling blending because it was better than nothing (maybe?), and then this version not being able to do even that much.
Really handling blends here is really hard, which is why we'd really rather do all forced phot on diffims.
We only care about single visit forced photometry for variable sources, thus we only need PSF flux, flags, and the centroid it was forced from.
These tests confirm that the tasks can be initialized and produce non-NaN output, but nothing more than that.
This makes it consistent with the newer ForcedPhotCcdFromDataFrameTask.
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Also added some trivial tests of the two tasks in forcedPhotCcd.py