Typically when playing with moons, each player draws two moons and places them in their system. Players may look at moons in their own system at any time. Moons are challenged like planets with the following exceptions:Unoccupied moons may be occupied immediately, without having to play a challenge card.
There are no alliances allowed in moon challenges.
Moon bases do not count toward the win.
Once a player occupies a moon, they may look at it, and follow the instructions. If it is a Play Now moon, they must reveal it and comply with the moon's effects. Secret moons need only be revealed when the player who occupies the moon desires. Some Secret moons are worthless, and have no effects.
See also: Moon Powers, Blue Moons, Eon Moon list, Mayfair Moon list, Moon Variants, and New Moons