Lunar New Year is the celebration of the first moon on the lunar calendar and lasts 15 days until the full moon. The lunar calendar is based on the phases of the moon. There are 29.5 days in a lunar month, and 354 days in a lunar month, and 354 days in a lunar year. The solar calendar, on the other hand, is based on how long it takes Earth to orbit the sun, which is 365 days.