c01d3ec read OpenNGC's addendum, which brought in its only two DrkN rows, C099 the Coalsack and
B033 the Horsehead; NGC.csv has none. classifyOpenNgcType mapped DrkN to 'nebula', so both were
drawn as the backdrop's nebula sprite: ff86b0, additive, at the faintest opacity and the 70 pc
minimum size, about 1.6° across. The review measured it adding up to +59 in red over the Coalsack
beside Crux, where the sky has a dark hole, and darkening no pixel, as an additive sprite cannot.
DrkN is now among the codes dropped, with the reason beside the map. fetchDeepSky from cache keeps
488 objects against 490, still 107 Messier objects and every required id; README's count follows.
On :4302 the served backdrop holds 488 objects and the scene 488 sprites, neither of them C099 or
B033.
Control: DrkN mapped back to 'nebula' fails "leaves out a dark nebula, which a sprite that adds
light cannot draw" (1 of 801).
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>