The mirror is mounted to the support pillar downtube. The mirror has two parabolic surfaces. The large mirror (dia=62mm) is shown here.
The reverse side has this smaller, more curved mirror (dia = 41mm).
Under the stage, mounted to the pillar is this condenser mounting mechanism. It has three centering screws (arrow) and two cutouts for the bayonette mounted condenser lens (now missing).
The condenser focus is via rack (shown here) & pinion.