Light – its presence and its absence, affects us in our awake and asleep state. Studies into light ‘s effect have resulted in the diagnosis of Seasonal Affective Disorder (SAD) with light therapy suggested for prevention and treatment. This light therapy can be as simple as getting outdoors more or employing specially designed indoor lights.
Other studies have found that light can disturb sleep, even the glow from a digital clock.
Moonlight is reflected sunlight and I don’t know of any studies that have revealed the benefits of exposure to the rays of the moon but direct experience has convinced me.