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Lose the PSF light that falls off the frame - #4
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MoffatPSF, EllipticalGaussianPSF and AiryPSF clipped their stamp to the frame and then normalised what was left, so a source on the edge kept its full flux. They now normalise the whole stamp first and deposit only the part on the detector, as GaussianPSF already did. A new test compares an edge source with the x >= 0 half of a fully captured image. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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Problem
MoffatPSF,EllipticalGaussianPSFandAiryPSFclipped their sampled stamp to the frame, then divided by the sum of what was left. A source near the edge therefore deposited all of its flux on the detector. A Moffat star centred on column 0 kept 100%, whereGaussianPSF, which integrates exactly, keeps about half. This breaks the stack convention that light lost at a detector edge is lost, not renormalised (aocore CONVENTIONS 3.3). It was found while migrating getframes onto aocore (#3).Fix
A shared
_deposit_sampledhelper evaluates the profile on the full(2r+1)²stamp, normalises it over that stamp, and then adds only the part that lands on the frame. Sources wholly inside the frame give the same images as before, to rounding.Tests
test_psf_loses_the_flux_that_falls_off_the_frame, for Gaussian, Moffat, EllipticalGaussian and Airy: an edge source must deposit exactly thex >= 0part of a fully captured image (rel 1e-9), and less than 75% of the flux. Moffat, EllipticalGaussian and Airy fail it onmain; all four pass with the fix.🤖 Generated with Claude Code