No English Term
An opaque screen covering part of a lantern, or placed outside the lantern, so as to provide a sharp cut-off to a beam in a sector light and to reduce the angle of uncertainty.
Note: This is a particular form of "cut screen".
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
Number of cells
International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM