Landmark information
- Location: 
 Currently: NE corner of Main St and Rams Head Grade, Volcano; Formerly located at Shake Ridge Rd, 1 mi W of Rams Horn Grade, outside Volcano
- Plaque: 
 Official State Plaque
- Site: 
 Nothing Remains
- Date First Visited: 
 3/1/1996
- Date Most Recently Visited: 
 10/19/2011
- GPS Coordinates: 
 N 38 26.571, W 120 37.879
About this landmark
                Plaque text: 
				
				Astronomical Observatory
				
				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 sun and moon, stars and planets, and other glories of the heavens, including the great comet of 1861. 
              
 
                  