1800-1900

Lohrmann, Wilhelm Gotthelf (1796-1840).

Topographie der sichtbaren Mondoberflaeche. – Dresden: Auf Kosten des Verfassers, 1824.

Lohrmann was a professional cartographer and surveyor who undertook a lunar map based on his own micrometric measurements. Using a small Fraunhofer refractor, he determined the exact position of a number of control points on the moon, from which the positions of all other lunar features could be determined. He divided his map into 25 sections, and in 1824 he published the first four of these sections, along with an explanation of his methods. Although he worked for sixteen more years, and finished drawing all the sections, Lohrmann never did publish the remainder of the atlas. Fortunately, his great successor Julius Schmidt undertook to have the drawings engraved, and the complete Lohrmann atlas finally saw the light in 1878 (see item 18).

One of the most attractive features of Lohrmann's maps is the use of multiple levels of shading to indicate light and dark areas of the moon. The detail is from the first section, and shows Mare Vaporum (Sea of Vapors) and what is now called Sinus Medii (Central Bay). Notable features include Hyginus rill at the bottom, Triesnecker just below center, and Hipparchus at the top. It is interesting that the space just left of Triesnecker is blank. Later observers would map an intricate rill system there (see item 31). Image source: Lohrmann, Wilhelm Gotthelf. Topographie der sichtbaren Mondoberflaeche. Dresden: Auf Kosten des Verfassers, 1824, sect. 1.

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