Visual Measurements of the Polarization of the Solar Corona
<p>Visual polarization measurements were made at the eclipse of February 14, 1934, with a modified Lyot-type polarimeter attached to a four-inch equatorially-mounted refractor. The objective was stopped down to 1 1/2 inches to reduce polarization effects the instrument. Distances from the moon...
| Summary: | <p>Visual polarization measurements were made at the eclipse of February 14, 1934, with a modified Lyot-type polarimeter attached to a four-inch equatorially-mounted refractor. The objective was stopped down to 1 1/2 inches to reduce polarization effects the instrument. Distances from the moon's limb were measured by means of a cross-wire reticle in the focal plane of the eyepiece.</p>
<p>Five different points of the corona were investigated, all lying directly off the east limb of the sun and ranging in distance from the limb from 1 to 8.5 minutes of arc. The observed polarization rose rapidly from 17% at 1' to 26% at 4', remaining sensibly constant from 4' outward.</p>
<p>These values are considerably higher than those previously obtained by visual methods, but are lower than the values obtained photographically. Subject to confirmation at a future eclipse, these values will constitute important evidence in favor of Schwarzschild's theory that a large part of the light of the corona is due to the scattering of photospheric light by free electrons.</p> |
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