George David Madeira (October 1836 – January 1922) was a mining engineer and mineralogist who founded the first astronomical observatory in California in the town of Volcano.
Although his formal education had ended at age 15, he continued to study mathematics from a neighbor, a Methodist minister from British Columbia named Telerand.
In 1860, he set up a crude observatory consisting of his telescope (which he had delivered from San Francisco), and a heavy canvas and oilcloth covering.
On October 18 of that year, the Sacramento Daily Union published a letter from him (under a pseudonym) regarding sunspot activity, the earliest recorded publication of astronomical research in California.
The family left Volcano for Carson City, Nevada in 1862 and Madeira sold his telescope to Josiah Whitney of the California Geological Survey.