Solar telescope
A solar telescope is a special purpose telescope used to observe the Sun. Solar telescopes usually detect light with wavelengths in, or not far outside, the visible spectrum.
Professional solar telescopes
Solar telescopes need optics large enough to achieve the best possible diffraction limit but they do not need the associated light-collecting power of other astronomical telescopes. Because solar telescopes are operated during the day and image a very bright object, and because the seeing limit imposed by atmospheric turbulence is much worse than that experienced by night-time telescopes, the objectives of such telescopes are about 1m or under in diameter. The heat generated by the tightly-focused sunlight also poses a design problem. Professional solar observatories may have main optical elements with very long focal lengths and light paths operating in a vacuum to eliminate air motion due to convection inside the telescope. Since this makes the telescope relatively massive (some are the most massive optical telescopes in the world), and the object that they image (the Sun) travels on a narrow fixed path across the sky, solar telescopes are usually fixed in position (sometimes buried underground) with the only moving part being a heliostat to track the sun. These telescopes use filtration and projection techniques for direct observation, in addition to filtered cameras of various types. Specialized tools such as spectroscopes and spectrohelioscopes are used to examine the sun in different wavelengths.Selected solar telescopes
See also List of solar telescopes- The Einstein Tower (Einsteinturm) became operational in 1924
- McMath-Pierce Solar Telescope (1.6 m diameter, 1961–)
- McMath-Hulbert Observatory (24"/61 cm diameter, 1941–1979)
- Swedish Vacuum Solar Telescope (47.5 cm diameter, 1985–2000)
- Swedish 1-m Solar Telescope (1 m diameter, 2002–)
- Richard B. Dunn Solar Telescope (1.63 m diameter, 1969–)
- Mount Wilson Observatory
- Dutch Open Telescope (45 cm diameter, 1997–)
- The Teide Observatory hosts multiple solar telescopes, including
- * the 70 cm Vacuum Tower Telescope (1989–) and
- * the 1.5 m GREGOR solar telescope nearing completion (, webcam).
- Advanced Technology Solar Telescope, a planned telescope with 4m aperture. http://atst.nso.edu/
Other types of observation
Most solar observatories observe optically at visible, UV, and near infrared wavelengths, but other things can be observed.- CERN Axion Solar Telescope(CAST), looks for solar axions in the early 2000s
- Multi-spectral solar telescope array ( MSSTA), a rocket launched payload of UV telecopes in the 1990s
- Leoncito Astronomical Complex operated a submillimeter wavelength solar telescope.
- The Radio Solar Telescope Network (RSTN) is a network of solar observatories maintained and operated by the U.S. Air Force Weather Agency.