(EN) A mirau reflected light interference microscopy accessory can be adapted asa two-beam interference accessory module (12) on the objective (1) of a microscope. The accessory has a reference mirror (6) and several separating mirrors (8a-8d) arranged on a revolving disk (7). The separating mirrors (8a-8d) have special reflection/transmission characteristics (R/T-values), in particular 20/80, 35/65, 43/57 and 50/50. The reference mirror (6) has for example 85 % reflectivity. This accessory allows objects (4) having different reflection values to be observed and measured without luminosity problems.