Johann Hieronymus Schröter (30 August 1745,

Erfurt Erfurt () is the capital (political), capital and largest city of the Central Germany (cultural area), Central German state of Thuringia, with a population of around 216,000. It lies in the wide valley of the Gera (river), River Gera, in the so ...

– 29 August 1816, Lilienthal) was a German

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

Life

Schröter was born in

, and studied law at

Göttingen University Göttingen (, ; ; ) is a college town, university city in Lower Saxony, central Germany, the Capital (political), capital of Göttingen (district), the eponymous district. The River Leine runs through it. According to the 2022 German census, t ...

from 1762 until 1767, after which he started a ten-year-long legal practice. In 1777 he was appointed Secretary of the Royal Chamber of

George III George III (George William Frederick; 4 June 173829 January 1820) was King of Great Britain and King of Ireland, Ireland from 25 October 1760 until his death in 1820. The Acts of Union 1800 unified Kingdom of Great Britain, Great Britain and ...

Hanover Hanover ( ; ; ) is the capital and largest city of the States of Germany, German state of Lower Saxony. Its population of 535,932 (2021) makes it the List of cities in Germany by population, 13th-largest city in Germany as well as the fourth-l ...

, where he made the acquaintance of two of

William Herschel Frederick William Herschel ( ; ; 15 November 1738 – 25 August 1822) was a German-British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline Herschel. Born in the Electorate of Hanover ...

's brothers. In 1779, he acquired a three-foot-long (91 cm, almost one metre) achromatic refractor with lens (50 mm) to observe the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

, and

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

. Herschel's discovery of

Uranus Uranus is the seventh planet from the Sun. It is a gaseous cyan-coloured ice giant. Most of the planet is made of water, ammonia, and methane in a Supercritical fluid, supercritical phase of matter, which astronomy calls "ice" or Volatile ( ...

in 1781 inspired Schröter to pursue

astronomy Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest includ ...

more seriously, and he resigned his post and became chief magistrate and district governor of Lilienthal. In 1784, he paid 31

Reichsthaler The ''Reichsthaler'' (; modern spelling Reichstaler), or more specifically the ''Reichsthaler specie'', was a standard thaler silver coin introduced by the Holy Roman Empire in 1566 for use in all German states, minted in various versions for the ...

(about 600 Euros of today) for a Herschel reflector of 122 cm focal length and 12 cm aperture. He quickly gained a good name from his observational reports in journals, but was not satisfied and in 1786 paid 600 Reichstaler (an equivalent of six months earnings) for a 214 cm focal length 16.5 cm aperture reflector with eyepieces allowing up to 1,200 magnification, and 26

Thaler A thaler or taler ( ; , previously spelled ) is one of the large silver coins minted in the states and territories of the Holy Roman Empire and the Habsburg monarchy during the Early Modern period. A ''thaler'' size silver coin has a diameter o ...

for a screw-micrometer. With this, he systematically observed Venus,

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...

and

Saturn Saturn is the sixth planet from the Sun and the second largest in the Solar System, after Jupiter. It is a gas giant, with an average radius of about 9 times that of Earth. It has an eighth the average density of Earth, but is over 95 tim ...

. Schröter made extensive drawings of the features of Mars, yet curiously he was always erroneously convinced that what he was seeing was mere cloud formations rather than geographical features. In 1791, he published an important early study on the topography of the Moon entitled ''Selenotopographische Fragmente zur genauern Kenntniss der Mondfläche''. The visual lunar albedo scale developed in this work was later popularised by Thomas Gwyn Elger and now bears his name. In 1793, he was the first to notice the phase anomaly of Venus, now known as the Schröter effect, where the phase appears more concave than geometry predicts. His two famous assistant astronomers were

Karl Ludwig Harding Karl Ludwig Harding (29 September 1765 – 31 August 1834) was a German astronomer, who discovered 3 Juno, Juno, the third asteroid of the main-belt in 1804. Life and career Harding was born in Lauenburg. From 1786–1789, he was educated a ...

(1796–1805) and

Friedrich Wilhelm Bessel Friedrich Wilhelm Bessel (; 22 July 1784 – 17 March 1846) was a German astronomer, mathematician, physicist, and geodesist. He was the first astronomer who determined reliable values for the distance from the Sun to another star by the method ...

(1806–1810). In 1813, he suffered the disruptions of the

Napoleonic Wars {{Infobox military conflict , conflict = Napoleonic Wars , partof = the French Revolutionary and Napoleonic Wars , image = Napoleonic Wars (revision).jpg , caption = Left to right, top to bottom:Battl ...

: his work was ruined by the French under Vandamme, who destroyed his books, writings and observatory. He never recovered from the catastrophe. His drawings of Mars were not rediscovered until 1873 (by François J. Terby) and were not published until 1881 (by H. G. van de Sande Bakhuyzen), well after his death. He was elected a member of the

Royal Swedish Academy of Sciences The Royal Swedish Academy of Sciences () is one of the Swedish Royal Academies, royal academies of Sweden. Founded on 2 June 1739, it is an independent, non-governmental scientific organization that takes special responsibility for promoting nat ...

in 1794 and elected a

Fellow of the Royal Society Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted by the Fellows of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural science, natural knowledge, incl ...

in April 1798. The lunar crater Schröter and the Martian crater Schroeter are named after him, as is Vallis Schröteri (Schröter's Valley) on the Moon.

References

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External links

Biography at the University of Bremen's Olbers Planetarium website
{{DEFAULTSORT:Schroter, Johann 1745 births 1816 deaths Scientists from Erfurt 18th-century German astronomers Selenographers University of Göttingen alumni Members of the Royal Swedish Academy of Sciences Fellows of the Royal Society Corresponding members of the Saint Petersburg Academy of Sciences 19th-century German astronomers

Life

See also

References

External links