High-resolution photography of the solar chromosphere

High-quality photographs of the solar limb and neighbouring regions of the disk at various wavelengths in the H line have been obtained through a tunable 1/8 Å filter used in tandem with a 1 Å Halle filter to eliminate parasitic light. The new observations throw further light on (a) the reappearance of the photospheric limb in the wings of H, and (b) the dark band lying immediately above the photospheric limb described by Loughhead (1969) and Nikolsky (1970). On the other hand, taken in isolation they add very little new information bearing on the question of the identification of spicules with disk structures.As a result of small temperature drifts in the 1/8 Å filter the stated wavelengths of the photographs given in Figures 1–4 may be in error by upwards of a few hundredths of an Ångström. Provision has since been made for setting accurately the zero of the wavelength scale by the method described by Bray and Winter (1970); this involves temporarily sliding the Halle filter out of the beam.