PHOTOMETRY OF THE SOLAR CHROMOSPHERE.
Environmental research papers (Doctoral thesis),
AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS
Pagination or Media Count:
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 suns 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 ergssq. 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