Assertion: telescope's objective | /r/CapableOf | make telescope
Facets:
value: with focal lengths
type: OTHER
Source sentences:
text: Christiaan Huygens and his brother made objectives up to 8.5 inches (220 mm) diameter and 210 ft (64 m) focal length and others such as Adrien Auzout made telescopes with focal lengths up to 600 ft (180 m).