30 November
1609: On 30 November 1609, Galileo Galilei used his telescope for the first time to study the Moon.
Galileo, at that time in Padua, Italy, turned his telescope toward the Moon, noted the irregularities of the crescent face, and made a drawing to record his discoveries. He made at least five more drawings of the Moon over the next eighteen days, prepared careful watercolour sketches from these drawings, and then selected four of these to be engraved for publication in the following March.
