An assembly (10, 10', 10") for switching optical paths in an optical microscope, said assembly comprising multiple optical channels for guiding light coming from a the- specimen to an image recording unit, the assembly further comprising a plurality of light guiding mirrors and at least one light modifying element in each optical channel for directing the light coming from the specimen, wherein t he light modifying elements each comprise third stationary light guiding mirror (18-i); and t he plurality of light guiding mirrors include the following mirrors: - a second rotatable light guiding mirror for guiding and for directing a light ray coming from the specimen to said third stationary light guiding mirror (18-i), and - a fourth rotatable light guiding mirror for directing the light ray reflected by one of the third light guiding mirrors (18-i) towards an image recording unit; wherein a rotating unit is coupled to the second and fourth light guiding mirrors (22, 42), and the rotational axis of said light guiding mirrors (22, 42) aligns with a common geometric axis; and wherein the respective optical channels and the associated third light guiding mirrors (18-i) are arranged around said geometric axis, the assembly being characterised in that the multiple optical channels are also for guiding an illuminating light ray to the specimen via the second rotatable light guiding mirror, wherein the light modifying elements comprise a stationary dichroic mirror (14a - i) and wherein each of the multiple stationary dichroic mirrors forms a pair with a respective one of the third stationary light guiding mirror (18-i) of each channel, wherein the second rotatable light guiding mirror is for guiding an illuminating light ray reflected by the stationary dichroic mirror (14a-i) to the specimen, wherein the stationary dichroic mirror (14a-i) passes light from the specimen to its associated third stationary light guiding mirror (18-i), and wherein the plurality of light guiding mirrors comprise a first rotatable light guiding mirror for directing the illuminating light ray to a selected one of dichroic mirrors of an optical channel, and wherein the first rotatable mirror is coupled to said rotating unit of the second and fourth light guiding mirrors (22, 42) such that the rotational axis of said rotatable light guiding first, second, and fourth mirrors align with said common geometric axis. t he light modifying elements each comprise third stationary light guiding mirror (18-i); and t he plurality of light guiding mirrors include the following mirrors: - a second rotatable light guiding mirror for guiding and for directing a light ray coming from the specimen to said third stationary light guiding mirror (18-i), and - a fourth rotatable light guiding mirror for directing the light ray reflected by one of the third light guiding mirrors (18-i) towards an image recording unit; - a second rotatable light guiding mirror for guiding and for directing a light ray coming from the specimen to said third stationary light guiding mirror (18-i), and - a fourth rotatable light guiding mirror for directing the light ray reflected by one of the third light guiding mirrors (18-i) towards an image recording unit; wherein a rotating unit is coupled to the second and fourth light guiding mirrors (22, 42), and the rotational axis of said light guiding mirrors (22, 42) aligns with a common geometric axis; and wherein the respective optical channels and the associated third light guiding mirrors (18-i) are arranged around said geometric axis, the assembly being characterised in that the multiple optical channels are also for guiding an illuminating light ray to the specimen via the second rotatable light guiding mirror, wherein the light modifying elements comprise a stationary dichroic mirror (14a - i) and wherein each of the multiple stationary dichroic mirrors forms a pair with a respective one of the third stationary light guiding mirror (18-i) of each channel, wherein the second rotatable light guiding mirror is for guiding an illuminating light ray reflected by the stationary dichroic mirror (14a-i) to the specimen, wherein the stationary dichroic mirror (14a-i) passes light from the specimen to its associated third stationary light guiding mirror (18-i), and wherein the plurality of light guiding mirrors comprise a first rotatable light guiding mirror for directing the illuminating light ray to a selected one of dichroic mirrors of an optical channel, and wherein the first rotatable mirror is coupled to said rotating unit of the second and fourth light guiding mirrors (22, 42) such that the rotational axis of said rotatable light guiding first, second, and fourth mirrors align with said common geometric axis.