Accession Number : AD0620220

Title :   PHOTOMETRY OF THE SOLAR CHROMOSPHERE.

Descriptive Note : Environmental research papers (Doctoral thesis),

Corporate Author : AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Personal Author(s) : Dunn,Richard B.

Report Date : JUN 1965

Pagination or Media Count : 159

Abstract : This report describes observations and measurements, made when there was no eclipse, of the hydrogen line H alpha in the chromosphere as it is observed at the sun's limp through a 3.4-A birefringent filter centered on H alpha. Descriptions of the telescope system and the photometric reductions are given. The introduction describes representative observations currently available for study of the chromosphere at the limb. The instrumental profile determined from measurements of images of a bright star, of narrow prominence features, and of the solar limb, is compared with laboratory measurements. A solar limb darkening curve is derived from observations made through the chromosphere camera. The results of the study extend from r = 0.9 to the solar limb. The H alpha intensity gradient is measured on some of the best pictures of the chromosphere obtained in 1955 and 1958. Measurements of the halfwidths of 42 spicules disclose that the average half-width is 815 km. The average value of the central intensity of the spicule is 2.5 x 10000 ergs/sq. cm sec steradian. At heights from 1000 to 3500 km the spicules are brighter than the adjacent background by 15 percent. Above 3500 km the contrast rapidly increases until it attains a value of 5 to 1 at 9500 km. Concluding remarks suggest further photographic studies of the chromosphere. (Author)

Descriptors :   (*SOLAR ATMOSPHERE, OPTICAL PROPERTIES), (*ASTROPHYSICS, SOLAR ATMOSPHERE), HYDROGEN, LINE SPECTRA, OPTICAL ANALYSIS, PHOTOGRAPHIC ANALYSIS, TELESCOPES, PHOTOMETERS, PHOTOGRAPHIC FILTERS

Distribution Statement : APPROVED FOR PUBLIC RELEASE