Real Time Digital Videomagnetograph At The Aerospace San Fernando Solar Observatory

Thomas J. Janssens

doi:10.1117/12.953607

16 April 1973 Real Time Digital Videomagnetograph At The Aerospace San Fernando Solar Observatory

Thomas J. Janssens

Proceedings Volume 0032, Developments in Electronic Imaging Techniques II; (1973) https://doi.org/10.1117/12.953607
Event: Developments in Electronic Imaging Techniques, 1972, San Mateo, United States

Abstract

Importance of Magnetic Fields In 1908, just 12 years after Zeeman discovered that magnetic fields cause a polarization and shift in certain spectral lines, Hale used this effect to detect the presence of strong magnetic fields in sun-spots. Further studies have shown that magnetic fields exist over the entire surface of the sun in very complicated patterns and determine the structures and motions of the solar plasma such as prominences, spicules, and flares. The very strongest fields of several thousand gauss cause the spectral lines to actually split but for weaker fields the Zeeman shift is only a small fraction of the line width and to measure this shift four steps are required: spectral dispersion or isolation of a magnetically sensitive line, selection of one state of circular polariza-tion, detection of the light intensity, and finally the subtraction of the light in the two opposite states of polarization. Spectral isolation can be achieved by a spectrograph or optical filter; the polarization states can be selected by an electro optic crystal or quarter wave plate with polarizer; the detector can be a phototube, film, or television camera; and the subtraction can be electronic, photographic, or digital. This paper describes a new type of solar magnetograph using digital techniques.

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Thomas J. Janssens "Real Time Digital Videomagnetograph At The Aerospace San Fernando Solar Observatory", Proc. SPIE 0032, Developments in Electronic Imaging Techniques II, (16 April 1973); https://doi.org/10.1117/12.953607

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KEYWORDS

Magnetism

Computing systems

Optical filters

Data storage

Televisions

Polarization

Sensors

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