NICOLAI, FRIEDRICH BERNHARD GOTTFRIED

(b. Brunswick, Germany, 25 October 1793; d. Mannheim, Germany, 4 July 1846)

astronomy.

After Nicolai had begun to study theology in Gottingen, he started to attend Gauss’s mathematics lectures. In 1813 he became an’assistant at the observatory at Seeberg near Gotha, which was then under the direction of Lindenau. When Schumacher left the observatory at Mannheim, Nicolai succeeded him as director, a position he held until his death.

Nicolai spent most of his career observing comets and planets. He made preliminary calculations of lunar occultations which were important in astronomical geography. In particular he pointed out the distorting influence of the profile of the moon.

Of greater influence were Nicolai’s works on the determination of differences of longitude from lunar observations. He modified a method devised in the first third of the eighteenth century, in which the right ascension of the moon could be determined by culmination observations. From this information, and with the aid of the ephemerides, the true time at the place of observation could be derived. Nicolai proposed that instead of measuring the culmination of the moon, what should be measured is the time between the transit of the rim of the moon through the local meridian and that of several nearby fixed stars of similar declination. The defective reduction to the center of the moon thereby became unnecessary, while at the same time the lesser error introduced by setting up the meridian telescope was not of great importance.

In pure mathematics, Nicolai worked on series expansions and integral functions. He improved the uncertain values of the mass of Jupiter by employing Gauss’s perturbation equations of the planetoid Juno.

BIBLIOGRAPHY

I. Original Literature. See “Berechnung der Meri-diandilTerenz zweier Orte, aus correspondirenden Monds—culminationen,” in Astronomische Nachrichten, 2 (1824), cols. 17–24. About eighty additional works that Nicolai published in Astronomisehcn Nachrichten are listed in H. Kobold, ed., Generalregister der Bände 1–40 der Astronomischen Nachrichten Nr. 1–960 (1821–1855) (Kiel,1936), cols. 78–79.

II. Secondary Literature. See the article by S. Gunther, in Allgemeine Deutsche Biographie, XXIII (Leipzig, 1886), 590–591. On the Mannheim Observatory and Nicolai’s activity there see G. Klare, “Ein Jahrhundert wechselvoller Geschichte der Mannheimer Sternwarte 1783–1883,” in Sterne und Weltraum, 9 (1970), 148–150. On his correspondence with Gauss, see W. Valentiner, ed., Briefe von C. F. Gauss an B. Nicolai (Karlsruhe, 1877).

Dieter B. Herrmann