Terry R Harris

US Patent:

51257432, Jun 30, 1992

Filed:

Dec 22, 1989

Appl. No.:

7/455678

Inventors:

David M. Rust - Silver Spring MD
John W. O'Byrne - Sunshot NM
Terry J. Harris - Baltimore MD

Assignee:

The United States of America as represented by the Secretary of the Air
Force - Washington DC

International Classification:

G01N 2121

US Classification:

356367

Abstract:

In a solar vector magnetograph for measuring solar magnetic fields including a telescope pointable to a solar zone and relay optics mounted there-behind, including a collimating lens, a quarter wave plate, a light polarizer, a beam expanding means, a narrow bandpass blocking filter to admit a narrow spectral band of polarized light, a reimaging lens to focus the resulting beam and an image receiver, the improvement provided is a solid Fabry-Perot etalon filter which is mounted between the blocking filter and the reimaging lens, such filter being of a desired refractive index and thickness so as to select a narrow band of the so-transmitted polarized light and to transmit same to the image receiver, all in order to isolate and record the emissions of atomic species and to infer the magnetic field at the solar zone. In another and preferred embodiment, the etalon filter is electrically tuneable to change its passband to select another narrow band of the transmitted polarized light and transmit it to the image receiver to record another image of the solar zone at the selected passband and compare with the image obtained at the previous passband to derive in greater detail a map of the intensity and the direction of the magnetic field in the solar zone, including the photosphere or the atmosphere thereabove so as to forecast solar flares and other disturbances based on solar magnetic field changes.