Apparatus, measurement method, and manufacturing method

An apparatus configured to measure eccentricity of an optical system based on a wavefront acquired for each target surface in a plurality of optical surfaces in the optical system, the apparatus comprising:

• a first light source configured to illuminate a chart including an index surface on which an index is provided;
• an objective lens configured to guide index light emitted from the chart to the optical system;
• a first element configured to receive the index light reflected on an optical surface in the optical system;
• and
• an interferometer configured to include a second light source and a second element, split light from the second light source into test light and reference light, receive light via the objective lens and the reference light with the second element, and acquire a wavefront of the measurement light, the measurement light being the test light reflected on the target surface.

A method for measuring eccentricity of an optical system based on a wavefront acquired for each target surface in a plurality of optical surfaces in the optical system, the method comprising:

• illuminating a chart including an index surface on which an index is provided;
• capturing an image by making index light emitted from the chart to enter the optical system via an objective lens and receiving the index light reflected on the plurality of optical surfaces in the optical system with a first element;
• splitting light emitted from a second light source into test light and reference light, receiving, with a second element, the reference light and measurement light that is the test light having passed through the objective lens and reflected on the target surface, and acquiring a wavefront of the measurement light;
• and
• reducing intensity of a signal of light reflected on an optical surface other than the target surface of the test light reflected on the plurality of optical surfaces and received by the second element in the acquiring.