Our Astronomical Column

Abstract

RECENT SOLAR ACTIVITY.—For several weeks there has been an absence of very large sunspots, although smaller ones, averaging half-a-dozen daily, have been of interest to observers with moderate telescopic means. In addition, facute at both limbs of the sun have been present on most days, some of the areas being of considerable extent. Traces of the facate related to the great spot of last December and January in north latitude 22° were seen about a fortnight ago. On June 21, a group of spots, the development of which had been watched since June 16, was of sufficient size to be a naked-eye object on the disc. The group consisted of a roughly circular spot as leader closely followed by a close cluster of small spots, which on some days linked up with one another to form a composite companion to the leader. On June 15, Mr. Newbegin, observing with his spectroscope at Button, Surrey, noted a metallic prominence (that is, one having a spectrum containing metallic lines) at position angle 63°, which corresponds almost exactly with the position of the newly forming spots then at the sun's east limb. This prominence, of the ‘rocket’ or ‘splash’ type, appeared as if the gases were being expelled from a common centre. Such prominences, according to Evershed and other observers, are very frequently found connected with sunspots, either during their active development, or at other times when great changes are taking place.