Assertion: reflecting telescope's mirror | /r/AtLocation | spherical
Facets:
value: in large focal ratios optical assemblies
type: OTHER
Source sentences:
text: In large focal ratios optical assemblies, both primary and secondary mirror can be left spherical and a spectacle correcting lens is added between the secondary mirror and the focal plane (catadioptric Yolo).
text: Smaller, longer focus mirrors can be left spherical - which is the easiest to make and test mirror shape - but will have residual amounts of spherical aberration (FIG.