The sky pieces can be found at different places in dizzywood:

1) the lighting bolt is at tanglevine jungle, its by the river.

2) the star is at explorers camp, by a tree at the right

3) the moon is at garden gazebo, by a orchard tree.

the reward is a blue moon, 250 coins, and a misson unlocked which is professer nouturnce flash cards, goodluck!!!