<![CDATA[#OnThisDay, 9 May 1922, the International Astronomical Union formally adopts Annie Jump Cannon's stellar classification system.]]>

<![CDATA[#OnThisDay, 9 May 1922, the International Astronomical Union formally adopts Annie Jump Cannon's stellar classification system.]]>#OnThisDay, 9 May 1922, the International Astronomical Union formally adopts Annie Jump Cannon's stellar classification system. The principles in it still underpin modern classification.

#WomenInHistory #OTD #History #WomensHistory #Astronomy #WomenInSTEM #AmericanHistory #Histodons

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