Observations of the Intermediate Solar Corona Outside of Eclipse. | doi.page

Observations of the Intermediate Solar Corona Outside of Eclipse.

The Astronomical Journal1964Vol. 69, pp. 553–553

Abstract

a balloon-borne externally occulted coronagraph (Newkirk and Bohlin, AppI. Opt. 2,131,1963) ascended to an altitude of 100 000 ft. During the 52~ h of observing time, 118 photographs of the streamers of the white light corona from 1.8 to 5.25 solar radii from the center of the solar disk were obtained. Exposures of 33, 100, and 300 sec duration were made on I-N 35-mm film. The effective wavelength of this system was 8300 A. Photometric standards on each photograph allow analysis of the brightness of the coronal streamers in terms of the brightness of the mean solar disk. Except for an interval centered about noon the coronagraph was guided on the sun to an accuracy of +5 sec of arc maximum excursion. Diurnal motion of the image of the corona as seen from the altazimuth guiding system allows one to distinguish between coronal streamers and artifacts due to the scattered light in the optical system. A level of scattered light in the coronagraph was approximately 10-~ the brightness of the mean solar disk. Inspection of the observations shows the corona of 5 March 1964 to be a typical sunspot minimum corona. Two complex streamers appear at the east limb while the west is dominated by a single, equatorial streamer extending to the limit of the field. Hypotheses connecting these streamers with recurrent geomagnetic storms and high-energy interplanetary nuclei observed during the early months of 1964 are presented. The Coronascope II project was supported by the Office of Naval Research, The National Science Foundation, and the National Aeronautics and Space Administration.

Abstract

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