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four times from the sloping faces of the prism, and exits the second flat face offset from, but in the same direction as the entrance beam. The image is rotated 180° in the process, and for this reason the prism is used as an
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For ease of manufacture, the prism is often made as a pair of double-right-angled prisms and the two halves cemented together. A single half of the assembly is sometimes also called a Porro–Abbe prism.
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It is made from a piece of glass shaped like four right-angled reflecting prisms joined face-to-face in a twisted fashion. Light enters one flat face, is
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since light enters and exits the prism only at normal incidence. Since the light is four times reflected, an even number of times, the image's
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Binocular Optics and
Mechanics Chapter from Binocular Astronomy by Stephen Tonkin, page 14 – 16
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OPTI 421/521 – Introductory
Optomechanical Engineering 5. Prisms, page 10
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59:to alter the orientation of an image. It is a
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16:Not to be confused with the dispersive
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142:Images of a Porro–Abbe prism
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51:, is a type of reflection
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20:or the non-dispersive
77:image erection system
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72:internally reflected
39:(sometimes called a
63:of the more common
57:optical instruments
65:double Porro prism
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31:A Porro–Abbe prism
93:The prism is not
22:Abbe–Koenig prism
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101:is not changed.
41:Abbe–Porro prism
37:Porro–Abbe prism
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156:Prisms (optics)
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55:used in some
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45:Ignazio Porro
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88:viewfinders
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99:handedness
95:dispersive
81:binoculars
49:Ernst Abbe
18:Abbe prism
150:Category
79:in some
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85:camera
83:, and
53:prism
47:and
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35:A
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