Origin story
Chandra, the moon god, emerged from the churning of the ocean and married the twenty-seven Nakshatras. His special fondness for Rohini is told in the Puranas, and his waxing and waning became the rhythm of the lunar calendar.
The crescent, the white horse and the soma nectar express coolness, mind and rejuvenation. Monday is his day, and in Kerala the moon is invoked at the start of festivals and family rites, when the lunar date decides the timing of the ritual.
Source: Wikipedia: Chandra — https://en.wikipedia.org/wiki/Chandra
