Lunar craters Lunar craters Lunar craters are impact craters on Earth's Moon. The Moon's surface has many craters, almost all of which were formed by impacts. The word "crater" was adopted from the Greek word for vessel - (Κρατήρ a Greek vessel used to mix wine and water). Galileo built his first telescope in late 1609, and turned it to the Moon for the first time on November 30, 1609. He discovered that, contrary to general opinion at that time, the Moon was not a perfect sphere, but had both mountains and cup-like depressions. These were named craters by Schroeter (1791), extending
Lovell Telescope from these original objectives, and are outlined in the following sections. In Autumn 1958, the telescope was used to bounce "Hellos" off the Moon for a demonstration in Lovell's third Reith Lecture. The telescope was also used to receive messages bounced off the Moon (a "moonbounce") as part of the 50th anniversary First Move festival. In April 1961, a radar echo from Venus was achieved using the telescope while the planet was at a close approach, confirming measurements of the distance of the planet made by American telescopes. The 21 cm hydrogen line was discovered during the telescope's construction; the