Sunrise halo

Study of a lighting effect caused by atmospheric dust and gases ejected by the 1883 volcanic eruption on the island of Krakatoa (Krakatau, Indonesia). A solar halo in the dawn twilight, observed in Hereroland, Kan-Thal (then German South West Africa) now the approximate region of Namibia, Africa, 4 September 1884. Plate 5 from the book Untersuchungen uber Dämmerungserscheinungen zur Erklarung der nach dem Krakatau-ausbruch beobachteten atmospharisch-optischen Storung, by J. Kiessling (Hamburg, Leopold Voss, 1888). The plate is inscribed above: ‘Kiessling, Dämmerung-Untersuchungen. Taf. V.’ Inscribed below: ‘KREISFORMER DAMMERUNGSSCHEIN BEI SONNENAUFGANG. [Circular twilight halo at sunrise]. Pechuel-Loesche. Hereroland, Kan-Thal, Sept. 4. 1884. Chromolithographie von Leo Kempner & Co. in Hamburg. Verlag von Leopold Voss in Hamburg (und Leipzig).’ Karl Johann Kiessling (1839-1905) German physicist, replicated twilight glow phenomena in the laboratory. Eduard Moritz Pechuël-Loesche (1840-1913) German naturalist and watercolour painter who travelled widely, including on expeditions to the Congo, Africa.