Assertion: comet | /r/HasProperty | observed through perihelion
Facets:
value: by 1900
type: TEMPORAL
Source sentences:
text: Once the comet had been observed through perihelion and its orbit had been established, the comet was given a permanent designation of the year of its perihelion, followed by a Roman numeral indicating its order of perihelion passage in that year, so that Comet 1969i became Comet 1970 II (it was the second comet to pass perihelion in 1970)
text: By 1900, seventeen comets had been observed through more than one passage through their perihelions, and then recognized as being periodic comets.
text: Once the comet had been observed through perihelion and its orbit had been established, the comet was given a permanent designation of the year of its perihelion, followed by a Roman numeral indicating its order of perihelion passage in that year, so that Comet 1969i became Comet 1970 II (it was the second comet to pass perihelion in 1970)