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Polarization Measurements from the 2 October 1959 Eclipse.

1960; Institute of Physics; Volume: 65; Linguagem: Inglês

10.1086/108295

1538-3881

William E. Felling, Michael Witunski,

History and Developments in Astronomy

During the total solar eclipse of 2 October 1959, a joint McDonnell Aircraft Corporation-U S AF Air Research and Development Command expedition to the Canary Islands made measurements of the magnitude and direction of the polarization of the coronal light. The observations presented in this report were made from an F-101B airplane, flying at 45 000 ft, well above the scattering influences of the earth's atmosphere. By flying at supersonic speeds, the airplane was able to remain in the umbral cone for 7. 6m5 18. An RB-47 from the 16th Air Force, flying along the path of totality at 30 000 ft, furnished the navigational assistance to set the F-101B on the desired course at the correct time. A Millikan DMB III 16-mm movie camera was used for the photography. This camera was equipped with a disk of Polaroid HN-32 mounted in front of the optical system. The disk was rotated 600 between each successive frame of film. A total of 178 frames of film have been analyzed in a microdensitometer built specially for this purpose. The magnitudes of the percent polarization in the region 2.5R0~R~5.5R0 are in fair agreement with the results from previous eclipses. The deviations in the direction of the magnetic vector from the radial direction are significantly larger, particularly in the equatorial region. The familiar, but unexplained phenomenon of greater light intensities across the lunar disk than in the outer corona (R> 3R0) was observed on all frames of film. This research was supported under USAF contract. %, and the direction of the polarization angle may be measured to an accuracy of ~0.8 deg. This equipment was successfully used on two sites in the Sahara Desert to measure the polarization of the corona during the eclipse of October 2,1959. At each of these two sites, successful data were obtained for five complete scans of the corona in each color of light. Results are presented in the accompanying paper by Ney, Kellogg and Huch (p. 352). This research was supported by the ONR, the NSF, and the NASA.