Drawing of a stellar spectrum by James E. Keeler, 1890

As in his drawing of Jupiter (also in this exhibit), Keeler's care and attention to detail are apparent in these exquisite drawings of the spectra of two stars, made with the help of a simple spectroscope—an instrument which spreads light out into its constituent colors for analysis—attached to the Lick 36-inch refractor. The pencil sketches on the right-hand page were made while observing. The more finished drawings on the left were made later, based on the sketches and notes.

Lick Historical Collections, manuscripts, Keeler observing books.