Astigmatism tester for reflective concave surfaces
OwnerJohn C. Shermaninventor
Life of this patent
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Abstract
A device to test reflective concave surfaces, such as telescope mirrors, and refractive convex surfaces for astigmatism, by providing a dot with which to examine an image of a point source which is formed by such surfaces. The dot is preferably held in the light path with a thin piece of optical glass. An additional embodiment has a plurality of dots, also preferably mounted on a piece of glass, with which to examine an optical system. The devices can also be used to test for asphericity of the surface.
Claims13
A device with which to test reflective concave surfaces and refractive convex surfaces for astigmatism and spherical aberration, comprising:
- a. a dot, and
- b. a means of holding said dot in an image formed by said surface,
- whereby said surface may be easily, inexpensively, and quantitatively tested for astigmatism.
A device with which to test reflective concave surfaces and refractive convex surfaces for astigmatism, comprising:
- a. a purality of dots, and
- b. a means of holding said dots in a light path formed by said surface,
- whereby said surface may be easily, inexpensively, and quantitatively tested for astigmatism.
A method of testing reflective concave surfaces and refractive convex surfaces for astigmatism and spherical aberration, comprising the steps of:
- a. using a point light source to illuminate said surface under test, and
- b. providing a dot, and
- c. providing a means of holding said dot in an image formed by said surface, and
- d. using a means to determine the degree to which an image formed by the system is rotationally symmetric,
- whereby said surface may be easily, inexpensively, and quantitatively tested for astigmatism.
A method of testing reflective concave surfaces and refractive convex surfaces for astigmatism, comprising the steps of:
- a. using a point light source to illuminate said surface under test, and
- b. providing a plurality of dots, and
- c. providing a means of holding said dots in a light path near an image formed by said surface, and
- d. using a means to determine the degree to which said image formed by the system is rotationally symmetric,
- whereby said surface may be easily, inexpensively, and quantitatively tested for astigmatism.
Dependencies are inferred from the claim text.