DIY Inspiration. Screen print/paint/embroider constellations on dark blue cushions. Use glow-in-the-dark paint. From the UFO Tree House in the Treehotel group in Sweden here. *TIP: For a list of constellations alphabetically and by month go here, then click on the link or google the name to find out how it looks.
*EDIT: If you decide to go with glow-in-the-dark paints there is a whole discussion about these paints on another post of mine - the Night Bike here. Go to www.glonation.com to see if this paint is right for you.