Solar photographs from 80,000 feet.

Abstract

view Abstract Citations (5) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Solar photographs from 80,000 feet. Schwarzschild, M. ; Rogerson, J. B., Jr. ; Evans, J. W. Abstract During the summer of 1957 three unmanned balloon flights have been carried out with the aim of obtaining direct solar photographs with high definition, undisturbed by atmospheric seeing. The first flight had the purpose of testing the pointing mechanism and carried only a dummy telescope. The full telescope, constructed by Perkin-Elmer Co., carried on the second and third flights, consisted of a parabolic mirror of ~~-inch aperture, f/8, an enlarging lens which produced an effective focal length of 200 feet, and a 35-mm movie camera taking an exposure each second with exposure time 0~.00I. The focus was scanned over a range of 10 to 20 times the focus tolerance. In the pointing control which was constructed by the Research Service Laboratories of the University of Colorado, photo- diodes were employed to find the sun and center on it. Motor-driven magnetic clutches were used to move the telescope with the motion in azimuth being accomplished by rotating against a heavy flywheel carrying the batteries. In the execution of the flights, carried out by General Mills, Inc., no serious difficulties were encountered in the launching, tracking and recovering of the equipment. The cost of repairs for launching damage averaged for each of the three flights about 5 per cent of the construction cost. *Presented at the 99th A.A.S. meeting, Indianapolis, Ind., December 27-30, 1957. Several exposures of very high definition were obtained, both of the center of the solar disk and of the limb. These exposures show that the solar granulation has a cellular though highly irregular character. The bright cells appear separated from each other by dark, often very sharp lines. The sizes of the elements seem to range from 2" down to 0'.'3. This project was sponsored by the Office of Naval Research and the Geophysics Research Directorate of the Air Force. Princeton University Observatory, Princeton, N. J., and Sacramento Peak Observatory, Sunspot, N. M. Publication: The Astronomical Journal Pub Date: September 1958 DOI: 10.1086/107766 Bibcode: 1958AJ.....63..313S full text sources ADS |