3. Turn the box on its side. On the wall facing up, which will span the projection length, cut out a viewing window. (Again, the size and placement are not critical, but the concept sketch might help.) 4. Use whatever large round object you have on hand (for example, a trash can lid) to cut two matching circles in your spare foam/cardboard. Use the glue gun to stick them onto the box, in the corner opposite to where the telescope will sit.