A telemeter without refractive optics.
A conic tube may be adjusted by varying the distal diameter and by using binocular vision for measuring distances. This device appears to be the earliest telemeter in the world. It is mentioned in the Talmud as being used in the first century A.D.
D049690:History, Ancient; D007585:Jews; D013686:Telemetry / Q000266:history / Q000295:instrumentation*