E. E. Barnard was an observer's observer. His prowess at the eyepiece is legendary. His most spectacular accomplishment as a visual observer was his 1892 discovery of Jupiter's faint moon, Amalthea, the first since Galileo had discovered the four brightest in 1610. (The next, Himalia, was discovered in 1904, also at Lick, but this time photographically.)

As a photographic observer, Barnard had few equals, and few astronomers of his day could match his skills in the darkroom. Barnard brought another essential quality to observing: enormous patience. Capturing the Milky Way with its low surface brightness called for long exposures, most in the range of two to five hours, some as long as ten. From beginning to end, the camera had to be guided by means of an attached telescope through which Barnard kept a constant watch on a guide star, making minute adjustments to keep it centered on a pair of cross hairs in the eyepiece. The quality of the photographs is testament not only to his skill, but also to his endurance.