Pleiades star cluster, 1898, original glass plate negative and a positive print

Above is a two and a quarter hour exposure of the Pleiades star cluster in the constellation Taurus, taken on December 10, 1898, with James Keeler's double-slide plate holder attached to the newtonian focus of Lick's 36-inch Crossley reflector. The image on the left is the glass plate itself at approximately life size; next to it is a positive made from the plate. Positives prints were generally only made for publication, teaching, or public consumption, the scientific analysis being performed on the original negative.

The picture at left shows the same plate, propped in a rack for drying, as it might have appeared in the darkroom after developing on the morning following the observation. Learn more.

Lick Historical Collections, photographic plate archive.