Southwest of Tucson, on the Tohono O'odham Reservation, Kitt Peak National Observatory offers visitors some of the best night skies in the world. Both daytime guided tours and nighttime viewing programs are available. During the night program, you'll view a variety of stars and planets and locate prominent night sky features.
If you go:
Call ahead to make sure programs and tours are offered that day. Allow 90 minutes driving time from downtown Tucson. Mountain temperatures vary considerably from the desert floor by 15 to 20 degrees and it is often windy, so dress warmly. In winter, bring hat, gloves and heavy jacket for the outdoor night program. The visitor center and grounds are open from 9 a.m. to 4 p.m. daily. Drive 12 miles up the mountain, until you see a 'giant concrete donut' with a mural painted on it. Turn left and park.
Links:

Kitt Peak Road
Arizona State Route 386
Three Points, Arizona 85736 USA
outreach@noao.edu
Mailing address:
National Optical Astronomy Observatory
PO Box 26732
Tucson, AZ 85726-6732 USA
Phone Numbers:
Visitor Information
+1 (520) 318-8726
+1 (520) 318-8726
Visitor Center Day
+1 (520) 318-8163
+1 (520) 318-8163