Mayer, Johann Tobias (1723–1762)

German cartographer, astronomer, and physicist. He improved standards of observation and navigation. He also produced a map of the Moon's surface and concluded that it had no atmosphere.

Mayer was born in Marbach, near Stuttgart. He learned architectural drawing and surveying and taught himself mathematics, French, Italian, and English. He published his first book, on the application of analytical methods to the solution of geometrical problems, at the age of 18. In 1746 he began work for the Homann Cartographic Bureau in Nürnberg. He became professor of economy and mathematics at the Georg August Academy in Göttingen 1751 and director of the observatory 1754.

At the Homann Cartographic Bureau, Mayer drew up around 30 maps of Germany. These established exacting new standards for using geographical data in conjunction with astronomical details to determine latitudes and longitudes on Earth. To obtain some of the astronomical details, he observed lunar oscillations and eclipses using a telescope of his own design.

His principal achievement was an improved set of tables of the Moon's position for use in navigation. Mayer's Lunar Tables 1753 were correct to one minute of arc. They were used by Maskelyne in his trial of the method of lunars, and in consequence Mayer's widow received a prize of £3000 from the Board of Longitude 1765.

Mayer also invented a simple and accurate method for calculating solar eclipses, compiled a catalogue of zodiacal stars, and studied stellar proper motion.