# The twilight handoff (equinox sweep): the run boots at game hour 6
# in the morning twilight (el -0.6: the twilight sun already lit) and
# sweeps through noon (el 37.7) into the dusk: the wall crossfade at
# el 16-14 (~frames 3050-3120), the twilight sun settling onto its low
# soft arc (reg el 26-30, the operator's eyeball geometry: cap 30,
# rise 0.3 - the full elevation sweep read as bouncy), the lamps
# igniting through true sunset (gas 0.39 at el 2.4, full at el <= 0),
# the LIT blue hour (b > r from el ~-3), and the burnout at el -6
# (~frame 3778) - the end of civil twilight, the meteorologically
# accurate span (TWSP 22: in a city the artificial light takes over
# from el -6, the chromaticity dip minimum, so the lamps own the
# night exactly where gaslit London would have lit them).
# frames: 4400
