眼がん視し観かん測そく

noun

visual observation

Technical term in astronomy for observing celestial objects with the naked eye or through a telescope without photographic or electronic recording.

• アマチュア天てん文もん家かは眼がん視し観かん測そくで流りゅう星せい群ぐんを記き録ろくした。

  The amateur astronomer recorded the meteor shower by visual observation.