Difference between revisions of "Prismatic Section"

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1. Cross-section of a prism by a plane normal to the refracting edge. The section is bounded by straight lines (usually three).
1. Cross-section of a prism by a plane normal to the refracting edge. The section is bounded by straight lines (usually three).


[[Image:Ch2_Fig11.jpg|400px]]
[[Image:Ch2_Fig11.jpg|400px|border]]




2. In lighthouse practice, the term is also used for a cross-section of a transparent optical element bounded by three straight or slightly curved sides, approximating to a triangle, but of such shape that incident parallel rays of a particular wavelength are focussed after refraction or reflection (or both) by the section.
2. In lighthouse practice, the term is also used for a cross-section of a transparent optical element bounded by three straight or slightly curved sides, approximating to a triangle, but of such shape that incident parallel rays of a particular wavelength are focussed after refraction or reflection (or both) by the section.


[[Image:Ch2_Fig10.jpg|400px]]
[[Image:Ch2_Fig10.jpg|400px|border]]


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{{IALAFooter}}

Revision as of 10:05, 25 February 2009

2-2-020

1. Cross-section of a prism by a plane normal to the refracting edge. The section is bounded by straight lines (usually three).

Ch2 Fig11.jpg


2. In lighthouse practice, the term is also used for a cross-section of a transparent optical element bounded by three straight or slightly curved sides, approximating to a triangle, but of such shape that incident parallel rays of a particular wavelength are focussed after refraction or reflection (or both) by the section.

Ch2 Fig10.jpg




Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)