Learn about the constellations and make a constellation viewer
tubes e.g.. pringles, papertowel centre or black card to make tubes.
Print out of a variety of constellations in circles big enough to fit over the end of the tube
Take tube and cover one end with baking parchment (Roll up the card into a tube and do the same)
Cut out circle with a constellation on and stick it to the end of the tube. Poke a cocktail stick through each of the star dots.
Hold/stick the constellation over the end of the tube. When they look through it they will be able to see the pattern the stars make in the constellation. Or, shine a torch through and they can shine the constellation onto the wall.