Celesta has two moons—as discussed previously—in a 3:2 resonance. They are named Yar (outer) and Nareton (inner). A month (31 or 32 days) is counted as a full orbit of the OUTER moon (which is 31.659 Celestan days). They both are smaller than Luna, but entirely spherical.

Every conjunction of the two Celestan moons—i.e., every two months—coincides with one of the sequential Day Festivals. The exception is the lunar conjunction at the turn of the lunar year, on which is celebrated LastDay—usually in one’s home town, with family and friends.