Some results concerning the automatic photometry of photographic chromospheric images

The results of an exploratory work on the use of a high-speed, computer-controlled flying-spot for quantitative photometry of solar H images are given. The used method is briefly illustrated and applied to the study of the photometric structure and evolution of some chromospheric active regions. Evolutive curves and isophotes for the 27 October 1969 plages (McMath 10381 and 10385) are presented.The brightness fluctuations of the center, border and node of the quiet chromospheric network are also analyzed; only a marked periodicity at 300 s is present, with a rms relative intensity of 6% for the center, 8% for the border, and 13% for the node of the quiet chromospheric cell. Some conclusions concerning the constraints on the analysis method and the observational material quality needed for an efficient, computer controlled, interactive photometry are drawn.