Method and apparatus for identifying and correcting spherical aberrations in a microscope imaging beam path

An apparatus for identifying a spherical error of a microscope imaging beam path, in a context of microscopic imaging of a sample, using a microscope with an objective and having a coverslip that carries or covers the sample being disposed in the imaging beam path, the apparatus comprising:

• an incoupling device configured to couple a measurement beam into the microscope imaging beam path of the microscope such that the measurement beam is incident in decentered fashion, outside an optical axis of the objective, through the objective onto the sample;
• an outcoupling device configured to couple the measurement beam reflected at an interface of the coverslip with the sample, after passing through the objective, out of the microscope imaging beam path of the microscope;
• a detector configured to acquire an intensity profile of the outcoupled measurement beam, the outcoupled measurement beam being imaged on the detector;
• and
• an evaluation unit configured to determine, at least one of qualitatively or quantitatively, a spherical error from the intensity profile.