Here in Volcano in 1860, miner and amateur astronomer George Madeira built California's first
astronomical observatory of record and operated it for two years. Using a three-inch refractor telescope
he studied the sun and moon, stars and planets, and other glories of the heavens, including
the Great Comet of 1861.
California Registered Historical Landmark No 715
Plaque placed by the State Department of Parks and Recreation in cooperation with the
Astronomical Societies of Stockton and Sacramento. Plaque placed first in 1968. Revised and relocated in 2004.