Tobias Mayer (17 February 172320 February 1762) was a German

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either ...

famous for his studies of the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

. He was born at Marbach, in

Württemberg Württemberg ( ; ) is a historical German territory roughly corresponding to the cultural and linguistic region of Swabia. The main town of the region is Stuttgart. Together with Baden and Hohenzollern, two other historical territories, Württ ...

, and brought up at Esslingen in poor circumstances. A self-taught

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...

, he earned a living by teaching mathematics while still a youth. He had already published two original geometrical works when, in 1746, he entered J. B. Homann's cartographic establishment at

Nuremberg Nuremberg ( ; german: link=no, Nürnberg ; in the local East Franconian dialect: ''Nämberch'' ) is the second-largest city of the German state of Bavaria after its capital Munich, and its 518,370 (2019) inhabitants make it the 14th-largest ...

. Here he introduced many improvements in mapmaking, and gained a scientific reputation which led (in 1751) to his election to the chair of economy and mathematics at the

University of Göttingen The University of Göttingen, officially the Georg August University of Göttingen, (german: Georg-August-Universität Göttingen, known informally as Georgia Augusta) is a public research university in the city of Göttingen, Germany. Founded ...

. In 1754 he became superintendent of the observatory, where he worked until his death in 1762.

Career

Mayer's first important astronomical work was a careful investigation of the

libration In lunar astronomy, libration is the wagging or wavering of the Moon perceived by Earth-bound observers and caused by changes in their perspective. It permits an observer to see slightly different hemispheres of the surface at different tim ...

of the

(''Kosmographische Nachrichten'', Nuremberg, 1750), and his chart of the full moon (published in 1775) was unsurpassed for half a century. But his fame rests chiefly on his lunar tables, communicated in 1752, with new solar tables to the ''Königliche Gesellschaft der Wissenschaften zu Göttingen'' (Royal Society of Sciences at Göttingen), and published in their transactions. In 1755 he submitted to the British government an amended body of manuscript tables, which James Bradley compared with the

Greenwich Greenwich ( , ,) is a town in south-east London, England, within the ceremonial county of Greater London. It is situated east-southeast of Charing Cross. Greenwich is notable for its maritime history and for giving its name to the Greenwich ...

observations. He found these to be sufficiently accurate to determine the Moon's position to 75", and consequently the

longitude Longitude (, ) is a geographic coordinate that specifies the east– west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek let ...

at sea to about half a degree. An improved set was later published in London (1770), as also the theory (''Theoria lunae juxta systema Newtonianum'', 1767) upon which the tables are based. His widow, with whom they were sent to England, received in consideration from the British government a grant of £3,000 (). Appended to the London edition of the solar and lunar tables are two short tracts, one on determining longitude by lunar distances, together with a description of the

reflecting circle Reflecting instruments are those that use mirrors to enhance their ability to make measurements. In particular, the use of mirrors permits one to observe two objects simultaneously while measuring the angular distance between the objects. While re ...

(invented by Mayer in 1752), the other on a formula for

atmospheric refraction Atmospheric refraction is the deviation of light or other electromagnetic wave from a straight line as it passes through the atmosphere due to the variation in air density as a function of height. This refraction is due to the velocity of ligh ...

, which applies a remarkably accurate correction for temperature.

Legacy

Mayer left behind him a considerable quantity of manuscript material, part of which was collected by G. C. Lichtenberg and published in one volume (''Opera inedita'', Göttingen, 1775). It contains an easy and accurate method for calculating

eclipse An eclipse is an astronomical event that occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another body or by having another body pass between it and the viewer. This alignment of three c ...

s, an essay on colour, in which three primary colours are recognized, a catalogue of 998

zodiac The zodiac is a belt-shaped region of the sky that extends approximately 8° north or south (as measured in celestial latitude) of the ecliptic, the apparent path of the Sun across the celestial sphere over the course of the year. The pa ...

al stars, and a memoir, the earliest of any real value, on the

proper motion Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more distan ...

of eighty stars, originally communicated to the Göttingen Royal Society in 1760. The remaining manuscripts included papers on atmospheric refraction from 1755, on the

motion In physics, motion is the phenomenon in which an object changes its position with respect to time. Motion is mathematically described in terms of displacement, distance, velocity, acceleration, speed and frame of reference to an observer and m ...

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin at ...

as affected by the

perturbation Perturbation or perturb may refer to: * Perturbation theory, mathematical methods that give approximate solutions to problems that cannot be solved exactly * Perturbation (geology), changes in the nature of alluvial deposits over time * Perturbat ...

s of

Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousand ...

and the

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's sur ...

(1756), and on terrestrial magnetism (1760 and 1762). In these last Mayer sought to explain the magnetic action of the Earth by a modification of

Euler Leonhard Euler ( , ; 15 April 170718 September 1783) was a Swiss mathematician, physicist, astronomer, geographer, logician and engineer who founded the studies of graph theory and topology and made pioneering and influential discoveries in ...

's hypothesis, and made the first really definite attempt to establish a mathematical theory of magnetic action (C. Hansteen, ''Magnetismus der Erde'', I, 283). In 1881 Ernst Klinkerfues published photo-lithographic reproductions of Mayer's local charts and general map of the Moon. His star catalogue was re-edited by Francis Baily in 1830 (''Memoirs of the Royal Astronomical Society'' IV, 391) and by

Arthur Auwers Georg Friedrich Julius Arthur von Auwers (12 September 1838 – 24 January 1915) was a German astronomer. Auwers was born in Göttingen to Gottfried Daniel Auwers and Emma Christiane Sophie (née Borkenstein). He attended the University of G� ...

in 1894. Honors: Lunar crater T. Mayer (Southwest of crater Copernicus).

Family

His son Johann Tobias Mayer became a noted German physicist.

Notes

References

* A. G. Kästner, ''Elogium Tobiae Mayeri'' (Göttingen, 1762) *Jérôme Lalande, ''Connaissance des Temps'', 1767, p. 187 *''Monatliche Correspondenz'', VIII, 257; IX, 45, 415, 487; XI, 462 *''Allgemeine Geographische Ephemeriden'' III, 116, 1799 (portrait) *A. G. Kästner, ''Berliner Astronomisches Jahrbuch'', Suppl. Bd. III, 209, 1797 *J. B. J. Delambre, ''Histoire de l'Astronomie au Dix-huitième Siecle'', (Paris, 1827), p. 429 *Robert Grant, ''History of Physical Astronomy from the Earliest Ages to the Middle of the Nineteenth Century'' (London, 1852), pp. 46, 488, 555 *Arthur Berry, ''A Short History of Astronomy'' (London, 1898), p. 282 *J. S. Pütter, ''Versuch einer academischen Gelehrten-Geschichte von der Universität zu Gottingen'', I, 68 *J. Gehler, ''Physikalisches Wörterbuch'' neu bearb. von H.W. Brandes .a. (Leipzig, 1825- ), VI, 746, 1039 * * Attribution: *

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