• mnemonic ⪢⪢
And if we zoom in on the visible portion we see some familiar colors.
http://qindex.info/i.php?x=7101

• stellar classification
-- specroscopy, Henry Draper, Annie Jump Cannon, Hertzsprung-Russel, deplete, luminous, luminosity, Edward, mnemonic
http://qindex.info/i.php?x=14595

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