Per-band v3 final difference images — 4×-oversampled residual grids
Stacked (D − local background)/F at Gaia DR3 positions (proper motion to the frame epoch) through each field's trained WCS (10-01 chain fit),
in 0.25 px bins (splat ±0.25 px for groups of ≥80 stars, ±0.5 px otherwise, marked “(1px)”). Outer 3×3 = CCD (y up); inside each cell rows = Tmag 13–14 / 14–15 / 15–17,
columns = BP−RP <0.8 / 0.8–1.5 / ≥1.5. Shared colour scale per field (% of star flux per native pixel). Stars: 13≤T<17, no T<13 star within 12 px, no brighter-than-T+1 neighbour within 4 px, r≤3.5 aperture good.
Script: perband_v3_20261005/scripts/final_resgrid_os4.py. Record: perband_v3_20261005/README.md.
