A moon appearance generating system for providing an enhanced depth perception to imitate a sky scene, for example, a natural sky scene at night, the moon appearance generating system comprising: a luminous device with a primary light emitting area that is configured to provide, when the moon appearance generating system is operated to imitate the sky scene, a two-dimensional spatial profile of a luminous flux density across the primary light emitting area with a mean luminous flux density value of at least 5 Im/m2, a maximum luminous flux density value of less than about 150000 lm/m2, wherein the mean luminous flux density value is at least 2% of the maximum luminous flux density value, wherein the luminous device comprises - a primary light source unit for providing a directed light beam of visible light; and - a mask unit configured to extend across the directed light beam in the near field and to form the primary light emitting area, wherein the mask unit comprises at least one absorbing element to locally absorb light and a diffuser element configured to locally increase the divergence across the directed light beam, such that the luminous flux density profile comprises at least one low luminous flux density region with a mean low luminous flux density value lower than 90 % of the maximum luminous flux density value, and at least 20% of the area of the primary light emitting area has a luminous flux density below the mean luminous flux density value, and a frame structure providing an exit aperture through which the primary light emitting area is completely viewable from within an enhanced depth perception observation range, wherein the exit aperture is associated with an inner frame line that surrounds at least an area of 20 cm width and 20 cm height, and wherein the primary light emitting area is configured to be viewable along an optical main path and is perceived as having a shape, which results, when the primary light emitting area is projected along the optical main path onto a frame front plane defined by the inner frame line, of a moon phase, and an optical main path length for light originating from the primary light emitting area until passing the exit aperture is at least about 0.3 m, such as 0.5 m. a luminous device with a primary light emitting area that is configured to provide, when the moon appearance generating system is operated to imitate the sky scene, a two-dimensional spatial profile of a luminous flux density across the primary light emitting area with a mean luminous flux density value of at least 5 Im/m2, a maximum luminous flux density value of less than about 150000 lm/m2, wherein the mean luminous flux density value is at least 2% of the maximum luminous flux density value, wherein the luminous device comprises - a primary light source unit for providing a directed light beam of visible light; and - a mask unit configured to extend across the directed light beam in the near field and to form the primary light emitting area, wherein the mask unit comprises at least one absorbing element to locally absorb light and a diffuser element configured to locally increase the divergence across the directed light beam, such that the luminous flux density profile comprises at least one low luminous flux density region with a mean low luminous flux density value lower than 90 % of the maximum luminous flux density value, and at least 20% of the area of the primary light emitting area has a luminous flux density below the mean luminous flux density value, and - a primary light source unit for providing a directed light beam of visible light; and - a mask unit configured to extend across the directed light beam in the near field and to form the primary light emitting area, wherein the mask unit comprises at least one absorbing element to locally absorb light and a diffuser element configured to locally increase the divergence across the directed light beam, a frame structure providing an exit aperture through which the primary light emitting area is completely viewable from within an enhanced depth perception observation range, wherein the exit aperture is associated with an inner frame line that surrounds at least an area of 20 cm width and 20 cm height, and wherein the primary light emitting area is configured to be viewable along an optical main path and is perceived as having a shape, which results, when the primary light emitting area is projected along the optical main path onto a frame front plane defined by the inner frame line, of a moon phase, and an optical main path length for light originating from the primary light emitting area until passing the exit aperture is at least about 0.3 m, such as 0.5 m.