Only the full moon. Any bright night. Superstition about the calendar.
Fig. II · LCAN
Plate III · teaching
Ignition key
full-moon geometry
Not any bright night.
Geometry plus spectrum. Not brightness.
A lamp at the same brightness does nothing. It has to be that moon, in that line, that colour, at night.
1 · Geometry
The sun, you, and the moon in a straight line. That alignment, not a calendar.
2 · Colour
Extra light at one blue-violet band, about 410–415 nm. Not ‘bright’.
3 · Night only
The eye is primed for dark. Noon sun has more of that colour and still does not fire it.
4 · Not a lamp
Streetlight at the same brightness does nothing. It drowns the key.
Opposition
~40%
Band
410–415 nm
Window
night only
Invoices of the same engine
Full-moon geometry
Trigger · Opposition geometryFiled reconstruction · LCAN · Full-moon geometry
Gibbous at 95% is ~30% below directional near-UV threshold. A lamp at equal lux does not replicate the geometry. Enucleation or a light-sealed room aborts the full shift.
The moon does not emit. At full moon the observer sits at zero phase angle: sun, observer, moon in a line, every surface shadow on the disc gone. Opposition surge adds about forty percent more brightness than a geometric model of the same disc. The surge itself is slightly stronger at shorter visible wavelengths, around 410 to 415 nanometres — melanopsin's secondary shoulder, not its 480-nanometre sky-blue peak. A lamp at the same lux does nothing. Intensity was never the trigger. Geometry plus that band is.
Noon sunlight carries orders of magnitude more 415-nanometre photons. does not fire then because the receptor is gated: melatonin must sit above a systemic threshold. Night only. Urban LED and fluorescent light raise the ipRGC floor until the moon's five-to-eight-times increment never arrives. Light pollution is not a lifestyle note. It is a switch. The calendar curse is an optical alignment the rest of mammalian photobiology had no reason to look for.
Ch. 1–2
Werewolves in Theory