Colour print showing solar prominences
1872
Set of three colour engravings with window mounts of colour sketches showing solar prominences observed and drawn by Etienne Leopold Trouvelot at the Harvard College Observatory by viewing the sun tangentially through a spectroscope attached to a telescope with the silt-jaws slightly open. Supervised by Prof. Winlock and published in the Annals of the Harvard College Observatory in 1876 with money from the Bache Fund.