- Ordinarily [the flag of the United States] should be displayed only between sunrise and sunset, although the Flag Code permits night time display “when a patriotic effect is desired.” Similarly, the flag should be displayed only when the weather is fair, except when an all-weather flag is displayed.
- It should be illuminated if displayed at night.
[…]
Out of practical necessity, five of the six U.S. flags standing on the moon (the Apollo 11 flag was blown over during departure) fly continuously, even during the two-week lunar night.