Traugott Leberecht von Ertel took over the " mathematical workshop" from his older business partner, the well-known designer Georg von Reichenbach, in Munich in 1821. He focused on the production of precise, high-quality geodetic instruments (especially theodolites) and astronomical instruments (transit telescopes). From 1834, the name was changed to T. Ertel & Sohn.
In the following years, the company changed owners, in 1912 it set up a special department for military contracts. After 1921, under the changed name Ertel-Werke für Feinmechanik, it manufactured geodetic, astronomical and special instruments, including instruments for the cinema industry. During World War II, it produced Enigma encryption machines, then it moved to Puchheim in 1957, and ceased to exist in 1984.