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Site of First Amateur Astronomical Observatory in California (No. 715 California Historical Landmark)

Historic Site or District
Great Comet of 1861 –

California Historical Landmarks Program

Historical Landmarks are sites, buildings, features, or events that are of statewide significance and have anthropological, cultural, military, political, architectural, economic, scientific or technical, religious, experimental, or other value. Historical Landmarks are eligible for registration if they meet at least one of the following criteria:

1) Is the first, last, only, or most significant of its type in the state or within a large geographic region

2) Is associated with an individual or group having a profound influence on the history of California

3) Is a prototype of, or an outstanding example of, a period, style, architectural movement or construction or is one of the more notable works or the best surviving work in a region of a pioneer architect, designer or master builder.

California’s Landmark Program began in the late 1800s with the formation of the Landmarks Club and the California Historical Landmarks League. In 1931, the program became official when legislation charged the Department of Natural Resources—and later the California State Chamber of Commerce—with registering and marking buildings of historical interest or landmarks. The Chamber of Commerce then created a committee of prestigious historians, including DeWitt Hutchings and Lawrence Hill, to evaluate potential landmark sites.

In 1948, Governor Earl Warren created the California Historical Landmarks Advisory Committee to increase the integrity and credibility of the program. Finally, this committee was changed to the California Historical Resources Commission in 1974. Information about registered landmarks numbered 770 onward is kept in the California Register of Historical Resources authoritative guide. Landmarks numbered 669 and below were registered prior to establishing specific standards, and may be added to the California Register when criteria for evaluating the properties are adopted.

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Although controversy surrounds the true location of the observatory, George Madeiros is widely recognized for building the first amateur observatory near the town of Volcano. Madeira operated the observatory from 1860 to 1862. Using his 3” refactor telescope, Madeiros saw the “Great Comet of 1861” soar across the sky, first observed by John Tebbutt of Australia on May 13.

The Great Comet was one of the brightest of all time. According to historical records and images, the Earth was actually within the comet’s tail for two days as it soared past the Earth. The comet was reported to be visible without a telescope between May and August.

George Madeiros was both a miner and an amateur astronomer. His observatory was thought to be both his home and observatory. He used sheets of cloth as the roof that he easily removed to view the stars, planets, sun and moon. By 1862, Madeiros left town and began lecturing on astronomy and writing newspaper articles. By the time he returned to Volcano in 1880, his observatory had been dismantled and completely removed from its site by 1910.

James Lick, a wealthy landowner, attended many of Madeiros’ lectures and was one of several people who inspired his interest in astronomy. According to local legend, in 1860 Madeiros told Lick "If I had your wealth ... I would construct the largest telescope possible to construct." Today, the Lick Observatory, established with a gift from James Lick, is located on Mt. Hamilton, east of San Jose and one of the University of California observatories.

Historical documents disagree on the true location of the Madeiros’ observatory. The first historical marker is located on Oak Ridge Road at what was thought to be the former site of his residence/observatory. A second marker has been placed in the town of Volcano that was also thought to be his home. This second marker is designated by the GPS coordinates. Since 1860 street names have changed and the layout of the town is also different, it is has been difficult to verify Madeiros’ residence address or the location of his observatory by using old maps and historic documents.

Amador County

Amador County was one of the most productive of the “Mother Lode” counties. The mine shafts were reported to be among the deepest in the world. Mining continues in select areas today. The eastern slope of Amador County begins at Kirkwood’s historic stage stop. The relatively narrow county is aligned between the Mokelumne and Cosumnes rivers and roughly follows an important emigrant trail route. Gold rush camps and boom-towns abound in the history of the area. Amador County is also recognized for its dozens of vineyards and wineries.

Time Period Represented


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