
%0 Journal Article
%A Bray, RJ 
%A Loughhead, RE 
%T High Resolution Observations of the Granular Structure of Sunspot Umbrae
%J Australian Journal of Physics
%D 1959/12/01
%V 12
%N 4
%P 320-326
%K 
%R https://doi.org/10.1071/PH590320
%U https://www.publish.csiro.au/paper/PH590320 
%X High resolution photographs of sunspot umbrae have confirmed the existence of an umbral granulation, resembling the photospheric granulation but differing in regard to lifetime and cell size. Bright structures in the form of " loops" are also seen. Quite apart from the granulation, the intensity contours of spot umbrae show a detailed and complex structure. 
