Measurement apparatus, measurement method, lithography apparatus and article manufacturing method

A measurement method of measuring a position of a target using a measurement apparatus that comprises an illumination system configured to illuminate the target with light including light of a first wavelength and light of a second wavelength different from the first wavelength, and a wavefront changing unit configured to change a wavefront aberration in light from the target, wherein

• the wavefront changing unit includes a first region where the light of the first wavelength enters, and a second region, different from the first region, where the light of the second wavelength enters, and
• the method comprises:
• acquiring a first wavefront aberration in the light of the first wavelength and a second wavefront aberration in the light of the second wavelength, and
• controlling the wavefront changing unit such that a first correction wavefront for correcting the first wavefront aberration is generated in the first region, and a second correction wavefront for correcting the second wavefront aberration is generated in the second region,
• wherein the first region and the second region are spatially separated regions on the wavefront changing unit, and light of the first wavelength and light of the second wavelength simultaneously enter the first region and the second region, respectively.