Tucson, Arizona uses sodium vapor lighting for all its street lighting specifically to allow the nearby observatories easily filter the light pollution.
I highly recommend it. The astronomy is fairly basic, but the experience is incredible: You're up on a big mountain, surrounded by gigantic telescopes, in the middle of a vast desert wilderness. It's freezing cold outside after dark. When the program is over, you have to drive down the upper half of the mountain without headlights to protect the observations that are happening.