MAPPING THE MOON
Since the invention of the telescope, many lunar observers have devoted their efoorts to mapping the seemingly endless geological detail of the Moon.
In 1610, Galileo Galilei was the first person to use a telescope to survey the Moon in detail through a full cycle of phases. His sketches were crude, but they were soon improved on by other astronomers. These early maps, with their plains, maps, with their plains, mountains, and craters, are still amazing to see, especially since they were done with unwieldy telescopes much interior to today's amateur scopes.
Many observers hoped to record changes in the Moon's features, but despaired of ever capturing by hand all the detail visible in their eyepieces. About a century ago, photography stepped in to offer a solution, and Moon charts today are usually based on photos, even if the final map is drawn or painted.
The era of lunar mapping has not yet ended. The Space Age brought new maps of the unseen far side of the Moon, as much more detailed maps of the near side. But it was only in 1996 that scientists were finally able to map the
Moon's global topography precisely, thanks to the laser altimeter on the Clementine spacecraft. The altimeter fired a laser beam at the ground, timing its return very accurately. With both Clementine's orbit and the speed of light being known, elevations landscape could be determined.