Johann Hieronymus Schröter (30 August 1745,Erfurt – 29 August 1816,Lilienthal) was a Germanastronomer.
Schröter was born inErfurt, and studied law atGöttingen University from 1762 until 1767, after which he started a ten-year-long legal practice.
In 1777 he was appointed Secretary of the Royal Chamber ofGeorge III inHanover, where he made the acquaintance of two ofWilliam Herschel's brothers. In 1779, he acquired a three-foot-long (91 cm, almost one metre)achromatic refractor with 2.25-inch (57 mm) lens (50 mm) to observe theSun,Moon, andVenus. Herschel's discovery ofUranus in 1781 inspired Schröter to pursueastronomy more seriously, and he resigned his post and became chief magistrate and district governor ofLilienthal.
In 1784, he paid 31Reichsthaler (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 26Thaler for a screw-micrometer. With this, he systematically observed Venus,Mars,Jupiter andSaturn.
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 entitledSelenotopographische Fragmente zur genauern Kenntniss der Mondfläche. The visual lunar albedo scale developed in this work waslater popularised byThomas Gwyn Elger and now bears his name. In 1793, he was the first to notice the phase anomaly of Venus, now known as theSchröter effect, where the phase appears more concave than geometry predicts.
His two famous assistant astronomers wereKarl Ludwig Harding (1796–1805) andFriedrich Wilhelm Bessel (1806–1810).
In 1813, he suffered the disruptions of theNapoleonic Wars: his work was ruined by theFrench underVandamme, who destroyed his books, writings and observatory. He never recovered from the catastrophe.[1]
His drawings of Mars were not rediscovered until 1873 (byFrançois J. Terby) and were not published until 1881 (byH. G. van de Sande Bakhuyzen), well after his death.
He was elected a member of theRoyal Swedish Academy of Sciences in 1794 and elected aFellow of the Royal Society in April 1798.[2]
The lunar craterSchröter and the Martian craterSchroeter are named after him, as isVallis Schröteri (Schröter's Valley) on the Moon.
One or more of the preceding sentences incorporates text from a publication now in thepublic domain: Chisholm, Hugh, ed. (1911). "Schröter, Johann Hieronymus".Encyclopædia Britannica. Vol. 24 (11th ed.). Cambridge University Press. p. 379.
