Assertion: kellner eyepiece | /r/HasAspect | narrow apparent field of view
Facets:
value: relatively
type: DEGREE
Source sentences:
text: Of the three eyepieces you mention you have in your collection, the K25mm and K12mm have the simple three-element design of a Kellner eyepiece which has a relatively narrow apparent field of view, although this may not be an issue for you when making lunar and planetary observations.