EVAPORATED SELENIUM FILMS FOR USE IN Ha PHOTOGRAPHY

0.75 Â passband and one of the chromosphere and prominences taken at the same wavelength with a 3 Â passband. This system permits study of the relationship between prominences and disk features. On April 30, 1960, while the instrument was still being adjusted, a sequence of pictures showing a fine set of loops over a large sunspot was obtained (Plate I). One end of the loops is seen clearly to be draining into the spot region. Although the photographs are not of the quality obtained when final adjustments were made, the phenomenon seems remarkable enough to be noted here. The spot associated with the loops shown in Plate I was a large single round sunspot, Zurich class H, just crossing the limb (Plate II). It is somewhat surprising that the loops occurred above what would normally be considered a stable sunspot. On the other hand, the spot gave issue to a number of importance 1 and 1~ flares, so it must have been a somewhat active region. It would be very interesting to have magnetic-field maps of such a spot region.