A shutter assembly for installation across an arched window includes a fixed shutter and a movable shutter coupled to the fixed shutter for rotation between open and closed positions. A permanent magnet is attached to the movable shutter for opposite-pole magnetic attraction coupling with a permanent magnet carried on a portable, hand-held actuator. The movable shutter is engaged magnetically and indirectly by placing the actuator end portion of the portable actuator in contact with the fixed shutter in an operative position proximate to the permanent magnet on the movable shutter. The movable shutter is then rotated either clockwise or counter-clockwise by sliding the actuator end portion along an arc across the face of the fixed shutter. The permanent magnet is concealed from view by the fixed shutter, thereby preserving its ornamental appearance.