Sukkot begins on the fifteenth of Tishrei, another full moon, and the rule for the temporary hut is that the roof must be loose enough to see stars through.

A week of eating and often sleeping outdoors, deliberately scheduled for the brightest nights of the month. The requirement that the covering be organic, cut, and thin enough to let the sky in is set out in detail in the Talmud, which makes it one of the few religious specifications anywhere that is effectively about visibility of the night sky.