Signedon top of optical tube assembly: CARL ZEISS / JENA [in lens logo]
Inscribedon optical tube assembly: Redta
serial number on tube assembly: Nr. 60749
FunctionA tachymeter (or tacheometer) is a surveying instrument used for the rapid determination of distances, elevations, and bearings.
Self-reducing double-image tacheometers are based on the system patented by Bosshardt in 1922. The first production model of the Zeiss–Bosshardt (Redta) self-reducing double-image tacheometer came out in 1927.
Primary SourcesRodolphe Bosshardt, Measure Optique des Distances et Methode des Coordonnees Polaires (1930).
Related WorksFritz Deumlich, Surveying Instruments (Berlin and New York: Walter de Gruyter, 1982), 293ff.