@25_cycle Cragg was an assistant at Mt Wilson, but also moved to siding spring observatory. This is his personal record that his wife provided after his death. @josemvaquero knows more. I find it fascinating that there are people keeping such meticulous r
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@rmathematicus @bhgross144 @atlasobscura This paper on the revised sunspot number mentions "Galileo, Gassendi, Staudacher, Schwabe, Wolf (small telescope), and Koyama"—and none of the astronomers you list above https://t.co/pboIcHpFEx
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RT @AstroPHYPapers: A Revised Collection of Sunspot Group Numbers. https://t.co/2bPt16YJM4
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RT @spaceweather: A Revised Collection of Sunspot Group Numbers https://t.co/XmTQHlJLX0