2.2.2 spase://SMWG/Instrument/EvansSolarFacility/Spectroheliograph Evans Solar Facility (ESF) Spectroheliograph 2012-05-03T00:00:00Z The National Solar Observatory's Evans Solar Facility is at Sacramento Peak, Sunspot, New Mexico. ESF is two telescopes in one, both tracking the solar cycle. A 16" coronagraphic telescope maps magnetic changes in the Sun's outer atmosphere. A special set of 12" coelostat optics "squints" so the Sun appears as a pinpoint, allowing an "apples and apples" comparison with the cycles of distant stars. The spectroheliograph is basically a specially designed camera that scans across an image of the sun, while letting only light from one particular color fall onto a light detector, such as film. It is possible for the spectroheliograph to pass light produced from the hydrogen or calcium atoms of the sun, for example. Because of the temperature and density variation with height in the solar atmosphere, and the resulting offset in differents types of atoms, the solar atmospheric structure at different heights can can be observed. See http://nsosp.nso.edu/esf/ spase://SMWG/Person/Stephen.L.Kell GeneralContact spase://vspo/instrument/75 Imager ESF Spectroheliograph spase://SMWG/Observatory/EvansSolarFacility