It was the Mid-Autumn Festival, and retiree William Koh, 66, took the opportunity to teach his 20-month-old grandson Barden Koh to count the lanterns hanging from a rope. At Bishan-Ang Mo Kio Park last night, families were out, armed with colourful lanterns and sparklers, to celebrate the festival, which falls on the 15th day of the eighth month of the Chinese lunar calendar, when the full moon is at its brightest. Traditionally, the festival marked the end of the autumn harvest. In Singapore, delectable mooncakes are the highlight of the season.