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. <EOS>