Assertion: telescope's system | /r/HasSubevent | flat field of sharp images
Facets:
Source sentences:
text: The Meade ACF, or Advanced Coma-Free telescopes retains the spherical primary mirror of their original Schmidt-Cassegrain telescope, but the secondary was replaced with a hyperbolic-figured secondary mirror and the figure of the full-aperture corrector plate was changed to produce a combined optical system that results in a flat field of sharp images right out to the edge of the field.