HIGH-RESOLUTION PHOTOGRAPHY OF SOLAR CHROMOSPHERE .7. STRUCTURE OF LOW CHROMOSPHERE

High-resolution observations of the low chromosphere beyond the limb at the centre of the Hα line reveal the existence of two types of fine structure whose presence has hitherto been unobserved: (1) small bright features which show a close correspondence in properties with the bright mottles on the disk and are unequivocally identifiable as the latter seen beyond the limb; and (2) a narrow dark band lying immediately above the photospheric limb whose physical significance is not yet clear. The discovery and identification of the bright mottles beyond the limb, taken in conjunction with recent observations of Bray (1969), lend further weight to the view that the chromospheric spicules are to be identified with the dark mottles seen on the disk. © 1969 D. Reidel Publishing Company.