There are 24 optical telescopes and 2 radio telescopes at Kitts Peak. This is the largest array of telescopes at one spot in the world. Almost any kind of space observation is done here from Solar observation to Near Earth Object tracking (watching for dangerous space objects that could hit the earth) to looking for planets like earth in deep space. 
Some of the observatories are open to look at and the first one we went to see was the Solar observatory. Its a huge building standing 100 feet above ground and 350 feet below ground. It tracks the sun during the day and collects data about sun spots, solar flares and temperature changes on the surface. This was one of the first observatories built in the early 1960's. 
The building consists of a 500 foot long tube mostly in the ground. At the top a large mirror tracks the sun and reflects its image into the tube and down to a reflecting mirror.
The mirror at the bottom of the tube reflects the suns image back up the tube to another mirror which sends the image to the monitoring equipment. There visual images as well as infrared images provide data about what the sun is doing. The whole giant tube is cooled to prevent internal heat waves from distorting the images. 
The biggest observatory, and the only one visible from Tucson is the 4 meter Mayall telescope. When it was built it was the second largest telescope in the world with a 4 meter wide reflecting mirror. Although built in the 1960's its still one of the best telescopes in the world and in great demand by astronomers around the world.
Not all observatories are open for viewing but you can walk almost anywhere to see them. Being 6800 feet in the air allows you to see for a long ways and the observatory site itself is lovely. There is much more greenery up here than down on the desert floor and its noticeably cooler.
Each of the observatories are on their own little hill so a lot of climbing is required to see them. At 6800 feet, we found we had to stop and catch our breath once in awhile.
There is no water on the mountain so all roads are designed to direct rain water into catch basins where the water is treated and sent to storage tanks. The 2 month rainy season has to produce enough water to last all year. 
After walking around to see the sights and going on a couple tours we had to rush back so we wouldn't miss happy hour. It felt good to take a load off and enjoy that most favorite of Mexican beverages, a margarita. Ah bliss!







