Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 127,910 pages of information and 202,084 images on early companies, their products and the people who designed and built them.
Information from The Planimetrica Collection website: Traugott Leberecht von Ertel (1778-1858). In 1806 he worked for Reichenbach, Utzschneider, und Liebherr (est. 1804, geodetic instruments), and left with Reichenbach. T. Ertel & Sohn established in 1821. 1850 address, Karls Strasse, Munich, near to G & S Merz, also established by Reichenbach. Sons: Georg Ertel (1813-1863); Gustav Ertel (1829-1875). In 1890, Diez purchased Ertel, and used the name T. Ertel & Sohn. In 1911, Julius Rinnebach joined the firm. By 1983, Ertel were specializing in theodolites.
Various Ertel & Sohn instruments are on display at the Deutsches Museum.