NO. 715 SITE OF FIRST AMATEUR ASTRONOMICAL OBSERVATORY OF RECORD IN CALIFORNIA - On the knoll behind this marker George Madeira built the first amateur astronomical observatory of record in California. It was there that he discovered the Great Comet of 1861 with a three-inch refractor telescope.
21335 Consolation St, Volcano, CA 95689 (See picture below for both sites)
The guidebook gives the location as: Shake Ridge Rd, 1 mi W of Rams Horn Grade, outside Volcano. (38.4658,-120.64045) However, the plaque at that location is missing. Articles in the "Stockton Astronomical Society" newsletter suggest that the old location was not correct. The new plaque is located at the address listed above. The new location, on Consolation Street, is "possibly" more accurate than the old one. ~~~~~~ (See picture below for both sites)
Revisited in July 2016 to take pictures of the old site.