noun
visual observation
Technical term in astronomy for observing celestial objects with the naked eye or through a telescope without photographic or electronic recording.
アマチュア天文家は眼視観測で流星群を記録した。
The amateur astronomer recorded the meteor shower by visual observation.
Compound of 眼視 (ganshi, 'visual inspection') and 観測 (kansoku, 'observation'). The exact historical derivation is uncertain; the term is used in modern astronomy.