Spherometer
instrument to measuare radius of curvature
A spherometer is an instrument used for the precise measurement of the radius of curvature of a curved surface. Originally, these instruments were primarily used by opticians to measure the curvature of the surface of a lens.
Design
A spherometer usually consists of:
A frame with three legs, arranged in an equilateral triangle of known radius. The outer legs of some spherometers can be moved to a set of inner holes in order to accommodate a smaller surface. The lower ends of the legs are finely tapered and terminate in hemispheres.
A central leg, which can be raised or lowered via a screw.
A reading device for measuring the distance the central leg is moved. Often this consists of a marked dial attached to the top of the screw and a vertical scale attached to the frame. This both indicates the number of turns of the screw and serves as an index for reading the divisions on the dial. A lens may be fitted in order to magnify the scale divisions.
This brief starts where responsible research should: with the source description of “Spherometer” as instrument to measuare radius of curvature. Everything that follows is an evidence route, not borrowed authority.
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The subject matters to the general reference register because the source frames it as instrument to measuare radius of curvature. Its deeper value depends on whether names, dates, institutions and citations support that framing.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Feb 3, 2025. The linked authority identifier is Q2154082. None of the 0 selected statements returned an explicit reference.
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This entry incorporates text from “Spherometer” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.