Cassini, Giovanni Domenico (1625-1712).

"Table pour le moyenne Libration & les Pleines Lunes," facing p. 140 in: Keill, John. Institutions astronomiques. – Paris: Chez Hippolyte-Louis Guerin, & Jacques Guerin, 1746.

In 1679, Cassini, the director of the Paris Observatory, published an engraved lunar map that was twice as large as those of Hevelius and Riccioli--fully 21 inches across. Based on drawings by Sebastian Leclerc and Jean Patigny, it was markedly superior in detail to its predecessors. Unfortunately, it was only printed as a broadsheet and very soon became unobtainable. However, reduced versions quickly began to appear in various optical and astronomical treatises, replacing, especially in France, the Hevelius and Riccioli maps as the standard. The Library has six different reductions published between 1694 and 1792; the most faithful is this one, included in the first French edition of John Keill's popular treatise on astronomy.

Much of the detail of the original Cassini map was lost in even the best reductions. One of the most delightful features of the 1679 map was the portrayal of Cape Heraclides on the Sinus Iridum (Bay of Rainbows) as a "moon maiden," complete with face and flowing hair. Here, the promontory (8, at bottom, right of center) has become virtually featureless. (For another view of the moon maiden, see item 32). Image source: Keill, John. Institutions astronomiques. A Paris: Chez Hippolyte-Louis Guerin, & Jacques Guerin, 1746, p. 140, pl. 2.

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