Tonight is the 15th day of the eighth Chinese lunar month which means that we can see the full moon hanging above us and shining bright in its full glory, weather permitting, of course.
One day while Yi went out hunting, someone named Fengmeng broke into the house and tried to force Chang-Er to give him the elixir. She refused and drank it herself. Chang-Er was transformed and flew upwards towards the heavens, choosing the moon as her residence. When Yi discovered what had transpired and felt sad, he displayed the Fruits and Cakes that Chang-Er had liked and offered them to her in worship.
That is why if you peer hard enough at the full moon in the eighth lunar month, you may see some semblance of the Moon Goddess dancing in the heavens.