Assertion: eyepiece's surface | /r/HasProperty | last tube baffle
Facets:
value: in a refractor
type: LOCATION
Source sentences:
text: The third limitation is the internal diameter of the last smallest obstruction before the focal surface, which may be the last tube baffle (in a refractor), the cylindrical or conical primary mirror baffle (in a Cassegrain), the opening in the visual back, or the internal diameter of the focuser drawtube (symbolized in the diagram above as opening z in relation to distance w):