Granulations on the Solar Surface ¹

Abstract

AN interesting research which promises fair to lead us to an increased knowledge concerning the nature of the sun's photosphere has recently been instituted by Prof. Hansky at the Pulkowa Observatory. On examining the splendid collection of photographs of the solar surface obtained by Prof. Janssen Wleudon, Prof. Hansky was not able to satisfy himelf that the whole of the réseau seen on the negative ws actually of solar origin; it seemed probable that some parts of it were produced by waves in our atmosphere, and on no two consecutive negatives, nor even on two taken simultaneously, could the same granules be recognised. For this reason he attacked the problem at Pulkowa, bringing into operation the astrographic telescope in order to obtain photographs on a large scale.