The invention relates to a large-
caliber aspheric surface
primary mirror detection device and method. The device includes a
point light source, a baffle, a measuring scale, a CCD (charge coupled
detector) and a
thin wire. According to the method, a
spherical wave emitted by the
point light source passes through an annular seam in the baffle and irradiates the mirror surface of a to-be-detected aspheric surface
primary mirror; then the
spherical wave is reflected by the mirror surface; the position of the baffle is adjusted, so that the light reflected by the mirror surface of the to-be-detected aspheric surface
primary mirror can pass through the annular seam in the baffle; a circle of bright
ray is formed at the
point light source; the
thin wire is used for
cutting at the
point light source; observing from the back of the
thin wire, a user can see that the bright
ray disappears; the CCD positioned behind the
point light source is used for shooting and recording images of the bright
ray; the
radius of the annulus of the bright ray and the distance from the light
point source to the to-be-detected aspheric surface primary mirror are measured. The position of the
point light source or the baffle is adjusted, and the
radius of the annulus of the bright ray and the distance from the light
point source to the to-be-detected aspheric surface primary mirror are measured, so that the
radius of curvature of a vertex of the to-be-detected aspheric surface primary mirror, a secondary constant and a
surface shape are figured out according to the aspheric surface primary mirror
surface shape formula.