The octagon-shaped building in the distance encloses the telescope of the WIYN Observatory. Completed in 1994, WIYN is owned and operated by the University of Wisconsin, Indiana University, Yale University, and the National Optical Astronomy Observatories. It was designed to provide the best possible image quality that the Kitt Peak site can deliver by reducing image degradation caused by air currents created by temperature differences between the telescope mirrors and the telescope structure and building. Unlike the older domes on the mountain, the WIYN enclosure allows wind to flow through it to carry away heat absorbed during the daytime and heat radiated by equipment in the building, and the primary mirror is cooled to maintain its temperature at nighttime observing conditions. The 3.5-meter (140 inch) diameter primary mirror is nearly as large as the 4-meter primary in the Mayall Telescope but weighs only one-tenth as much, allowing additional weight savings in the telescope structure and helping complete the observatory at a fraction of the replacement cost of telescopes built in decades past.