cyber-valley/policies/light policy.md

light governs plant cycles, animal behavior, and human sleep. cyberia treats outdoor light as managed, not ambient.

color temperature

  • all outdoor fixed lighting: 2200 K or warmer (amber spectrum)
  • warm color prevents circadian disruption in humans and suppresses the confusion effects on insects, amphibians, and nesting birds that broadband white causes
  • blue-enriched (> 3000 K) lighting prohibited outdoors anywhere on the estate

direction and shielding

  • all outdoor luminaires fully shielded: light directed downward, zero upward emission (full cutoff IES classification)
  • no floodlights illuminating canopy or forest understory
  • path lighting: ground-level bollards at maximum 0.6 m height preferred over pole-mounted fixtures

intensity limits

zone max illuminance at surface
paths and entrances 20 lux
parking and service 10 lux
forest edges and gardens 5 lux
conservation buffer 0 lux (unlit)

curfew

  • non-essential outdoor lighting off by 23:00 or end of last event, whichever is later
  • security lighting: motion-activated only, minimum 30 s timeout, no continuous-on fixtures
  • decorative string lights: off by 23:00

sky quality

cyber valley sits away from urban light domes — the Milky Way is visible on new moon nights. maintaining this matters for:

  • species that navigate by starlight (insects, birds, sea turtles if near coast)
  • cultural and scientific value of a dark sky
  • astronomical observation

target: Sky Quality Meter (SQM) reading > 21.0 mag/arcsec² at zenith on new moon nights

indoors

  • no requirement for indoor color temperature — residents choose their own light environment
  • recommendation: shift to 2700 K or amber by 20:00 to support natural melatonin onset

see also

zoning system, sound policy, carbon policy

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