Optical assembly with removable section

An optical assembly (16) for a precision apparatus (10) includes an optical element (234) and a housing (230) that defines a housing cavity (244). The housing (230) includes a body section (238), a removable section (240) and a fastener assembly (242). The body section (238) is secured to an apparatus frame (12) of the precision apparatus (10). The removable section (240) retains the optical element (234) with the optical element (234) positioned in the housing cavity (244). The fastener assembly (242) selective secures the removable section (240) to the body section (238). With this design, the removable section (240) can be selectively removed to repair or replace the optical element (234) and the optical element (234) is supported by a rigid mechanical housing (230) so that the optical element (234) is less susceptible to long term or operating misalignments.