Diodes

Light-emitting diodes or LEDs need a lot less energy.

Hunter's partner in the dark skies group, astronomer David Crawford, says the organization is working with industry to improve lighting. He cites technological advances such as light-emitting diodes, the kind of light used in cellphones. They run cool and save energy, but can also be night-friendly because they project light only where directed, not in all directions like incandescent bulbs.