Actually...
The Island cooperated with the observatories and uses primarily Na vapor lamps for outdoor lighting, and good upward shielding- I thought about having my glasses coated to reject 589nm (sodium D2 transition wavelength), but I wouldnt see streetlights at night. The observatories filter out the sodium light...
BTW my laser is not solid state- it is a dye laser- it is essentially 9 lasers that work together to produce 20 W at 589 nm- 6 high power frequency doubled YAGs pumping 3 ethanol/dye cells. We recently got funding to develop/buy a solid state sodium laser to put on Keck 1.