McMath–Pierce solar telescope

McMath–Pierce Solar Telescope

Alternative names	McMath–Pierce Telescope
Named after	Robert Raynolds McMath, Keith Pierce
Location(s)	Kitt Peak National Observatory , United States of America
Coordinates	31°57′30″N 111°35′42″W / 31.9584°N 111.595°W / 31.9584; -111.595Coordinates: 31°57′30″N 111°35′42″W / 31.9584°N 111.595°W / 31.9584; -111.595
Organization	National Solar Observatory
Altitude	2,096 m (6,877 ft)
Observing time	79 percent sign
Wavelength	Visible and infrared
Built	– (–)
Telescope style	reflecting telescope, solar telescope
Number of telescopes	3
Diameter	161 cm (5 ft 3 in)
Angular resolution	0.7 second of arc
Collecting area	2.04 m2 (22.0 sq ft)
Focal length	87 m (285 ft)
Mounting	Equatorial mount with heliostat
Enclosure	Slanted tower
Website	nsokp.nso.edu/mp/
Location of McMath–Pierce solar telescope
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McMath–Pierce solar telescope is a 1.6 m f/54 reflecting solar telescope at Kitt Peak National Observatory in Arizona, United States. The building was designed by Myron Goldsmith and built in 1962. It is the largest solar telescope and the largest unobstructed aperture telescope in the world. It is named for astronomers Robert McMath and Keith Pierce. At the dedication in 1962, Dr. Waterman read a letter from President Kennedy starting with:

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 uses the heliostat at the top of its main tower to direct the sun's light down a long shaft to the primary mirrors. The distinctive diagonal shaft continues underground, where the telescope's primary mirror is located. The theoretical resolution of the main telescope is 0.07 arcsec, although this is never reached because atmospheric distortions degrade the image quality severely. The image scale is 2.50 arcsec/mm at the image plane. Since 2002 the National Solar Observatory staff have developed an adaptive optics system designed for the unique needs of solar observatories that dramatically improve the resolution of science images.

The secondary telescopes are called East and West. They are completely independent of the main telescope. These two auxiliary telescopes each have a 0.91-meter heliostat located beside the main heliostat. These auxiliary telescopes have a slightly shorter focal length and f-numbers of 50 and 44. The resolution of the auxiliary telescopes is 5.11 arcsec/mm and 5.75 arcsec/mm.

The enclosure of the telescope was designed and engineered by the Chicago office of Skidmore, Owings and Merrill.