Display device for a timepiece for displaying a set of Moon phase representations reproducing the image of the Moon in the sky; said display device being configured to function according to a primary operating mode and according to a secondary operating mode and comprising: - A Moon disk; said at least one Moon disk comprising said set of Moon phase representations; said set of Moon phase representations including at least three Moon phases and each Moon phase of said at least three Moon phases being configured to have a first surface, a second surface and a delimitation configured to delimit said first surface and said second surface; - An aperture; said at least one aperture being configured to reveal said set of Moon phase representations; and, - A drive organ; said at least one drive organ being configured to rotate said at least one Moon disk around a first axis in said primary operating mode and to rotate said at least one aperture around a second axis in said secondary operating mode. said Moon disk being configured to be rotatable around said first axis between at least a first primary position and at least a second primary position in said primary operating mode, and said aperture being configured to be rotatable around said second axis between at least a first secondary position and at least a second secondary position in said secondary operating mode, said first axis and said second axis being coaxial; said display device comprising a control unit configured to control the movement of said Moon disk between said at least a first primary position and said at least a second primary position via the drive organ in said primary operating mode and to control the movement of said aperture between said at least a first secondary position and said at least a second secondary position via said drive organ in said secondary operating mode, the movement of said Moon disk in the primary operating mode and the movement of said aperture in the secondary operating mode being simultaneous or independent. - A Moon disk; said at least one Moon disk comprising said set of Moon phase representations; said set of Moon phase representations including at least three Moon phases and each Moon phase of said at least three Moon phases being configured to have a first surface, a second surface and a delimitation configured to delimit said first surface and said second surface; - An aperture; said at least one aperture being configured to reveal said set of Moon phase representations; and, - A drive organ; said at least one drive organ being configured to rotate said at least one Moon disk around a first axis in said primary operating mode and to rotate said at least one aperture around a second axis in said secondary operating mode. said Moon disk being configured to be rotatable around said first axis between at least a first primary position and at least a second primary position in said primary operating mode, and said aperture being configured to be rotatable around said second axis between at least a first secondary position and at least a second secondary position in said secondary operating mode, said first axis and said second axis being coaxial; said display device comprising a control unit configured to control the movement of said Moon disk between said at least a first primary position and said at least a second primary position via the drive organ in said primary operating mode and to control the movement of said aperture between said at least a first secondary position and said at least a second secondary position via said drive organ in said secondary operating mode, the movement of said Moon disk in the primary operating mode and the movement of said aperture in the secondary operating mode being simultaneous or independent.