In 1881, Sir William Huggins made the first photographic spectrum the first photographic spectrum of a comet (1881 III) and discovered the cyanogen (CN) emission at violet wavelengths. (This fact caused near mass hysteria 29 years later as the Earth passed thru the tail of Halley's Comet and some persons worried about the effect of this for life on Earth.) The first spectroscopic observations of comets were made made by Giovanni Donati (1864) and by Huggins in 1868 when he visually compared the spectrum of comet Winnecke (1868 II) with flame spectra and found that the bands seen in the comet and in the flame, now known as the “carbon” or “Swan Bands” were similar. Spectroscopy soon became the standard technique for studying the light of comets.[Ref: W. Huggins, "Preliminary Note on the Photographic Spectrum of Comet b, 1881," Proceedings of the Royal Society 33 (1881): 1-3.]