stenometer
noun
ste·nom·e·ter
stə̇ˈnämətə(r),
-mətə-
: an instrument for measuring distances consisting of a telescope mounted on a tripod and fitted with a micrometer screw so that the distance may be measured to a rod carrying two targets a known distance apart whose images are brought together in the telescope by the micrometer screw
Word History
Etymology
sten- + -meter