Assertion: telescope's mirror | /r/HasProperty | spherical
Facets:
value: for ease of manufacturing
type: PURPOSE
Source sentences:
text: The earliest reflecting telescopes used spherical mirrors, which although easy to fabricate and test, suffer from spherical aberration; a very long focal length was needed to reduce spherical aberration to a tolerable level.
text: The Schmidt telescope had a spherical primary mirror at the back of the telescope and a glass corrector plate in the front of the telescope to remove spherical aberration.
text: All telescopes which utilize both mirror and lens optics require some type of corrector lens when the primary mirror is a spherical surface design.
text: It had a spherical mirror with an aperture of 1 inch and a tube length of 6 inches.
text: If the mirror is spherical, it will suffer from spherical aberration.
text: Modern variants may have a hyperbolic primary for increased performance (for example, the Ritchey–Chrétien design); and either or both mirrors may be spherical or elliptical for ease of manufacturing.