McMath–Pierce solar telescope is a 1.6 m f/54 reflecting solar telescope at Kitt Peak National Observatory in Arizona, United States. Built in 1962, the building was designed by American architect Myron Goldsmith and Bangladeshi-American structural engineer Fazlur Rahman Khan. It was the largest solar telescope and the largest unobstructed aperture optical telescope in the world. It is named after the astronomers Robert Raynolds McMath and Keith Pierce. It was originally called the McMath Solar Telescope, and then later renamed the McMath-Pierce Solar Telescope in 1992. Although it is designed for observation of the Sun, it can also be used to view bright objects at night.In 2018, the telescope received a 4.5 million USD grant for an enhanced visitor center and other programs, and to overall revitalize the national icon. Construction The telescope is a triple instrument. In addition to the primary 1.61 m mirror fed by the 2.03 m heliostat, there are a pair of telescopes fed by 0.81 m heliostats mounted beside the main heliostat. These two instruments have 1.07 m and 0.91 m primary mirrors.The telescope...