The moon brightens for 14 days and then starts dimming for about the same and is not visible for a day.
Newbee, seriously ask yourself if you can really see much by moonlight, what our competitors sell is a night light, in relation to the sun the moon is if I recall about 1/1,000,000th the intensity. If you properly install it so it is angled gently down the length of the aquarium it does sufficiently illuminate an aquarium up to 6ft long and 2 ft wide to be an accurate representation of the moon in proportion to Metal Halide lighting.