noun, noun or participle which takes 'suru', transitive verb
astronomical observation; celestial navigation; shooting the sun
Technical term for determining position by observing celestial bodies, especially in navigation. 'Shooting the sun' is a nautical colloquialism.
航海士は六分儀で天測を行った。
The navigator performed a celestial observation with a sextant.
天測によって船
Determine the ship's position by celestial navigation.