Ejnar Hertzsprung’s letter to The Observatory

Ejnar Hertzsprung’s letter in the 1923 February issue of The Observatory in which he disowned any credit for the three-letter abbreviations of the constellations adopted by the IAU. Hertzsprung’s own two-letter list was published in Annalen van de Sterrewacht te Leiden. In line 2 of the letter below, the reference to p. 12 should read p. 22.