The Face of the Moon

8. Hooke, Robert (1635-1703).

Micrographia . -- London: Printed by Jo. Martyn and Ja. Allestry, 1665.

This seminal work on microscopy is more noted for its impressive engravings of magnified insects than for its contributions to lunar topography. The work, however, contains the very first attempt to delineate a particular lunar feature, in this case the crater Hipparchus, which is just south of the center of the moon. Hook also attempted to determine whether lunar craters were formed by impact or by volcanic action. He dropped balls into wet clay to simulate impact, and heated alabaster to produce bubbling volcanoes, and decided that the moon more closely resembled the pock-marked alabaster.

image - click to enlarge

To make this drawing, Hooke used a 30-foot long telescope and observed just before first quarter, when the shadows were strong. His drawing can be favorably compared with those of later observers (see items 13 and 15) and is a considerable improvement over the undefined circles that appear on the maps of Hevelius or Riccioli. Hooke further suggested that since the floor of Hipparchus reflected less light than the mountain tops, perhaps it was covered with vegetation and might be, in his words, a "fruitful place".

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