PURPOSE: To demonstrate the difference in spherical aberration between concave spherical and parabolic mirrors.
DESCRIPTION: A double optical board mirror assembly includes circular and parabolic mirrors with the same focal length. The circular mirror focuses parallel rays with aberrations as seen in the photograph at the left. Rotating the assembly inserts the parabolic mirror, which is free from spherical aberrations, as can be seen. The number and spacing of rays can be varied by choice of slit baffle and position of slit baffle. A slit baffle is available for which rays at different distances from the central ray are colored differently. A pair of concave and convex lenses at the left in the photograph are used to produce the parallel rays.
REFERENCES: (PIRA unknown.)
EQUIPMENT: Optical board with combination concave spherical and parabolic mirrors, concave and convex lenses.
SETUP TIME: None.
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