Elementary optics and applications to fire control instruments (1922)
United States. Army. Ordnance Dept · Washington, Govt. Print. Off. · leaf 30
makes this prismuseful in range fin-ders. The anglesmeasured by therange finder are sosmall that if a con-stant deviationprism were notused the variationin the angles of de-viation at the endreflectors broughtabout by the flex-ure of the tube andconsequent rota- … / 1 / / J?^ \ 1 1 ^> k Fir.. 2S.—Rhomboidal prism. fore substituted. Two silvered Fin. 27. —Ppnla prism. tion of the prisms would be suffi-cient to impair the accuracy of therange finder. 11 is necessary to sil-ver the reflecting surfaces of thepenta prism, as the rays fall uponthe reflecting…
Optics · Optical instruments · Fire control (Gunnery) -- Optical equipment
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