Rachel,
how much fun to recreate the constellations with bodies. My Brownie Guides did a similar activity at an adventure centre, they had to make different letters of the alphabet while lying on the ground, and use all the members of the six.
Do you think your children will design 4 pointed, 5 pointed, 6 pointed stars? You could show them some found in art or in quilting, where 8 pointed stars are common.
I have used this folding activity to make a 5 pointed star -good for 2nd and up because of the hand strength needed to cut through 10 layers of paper.