This is from an 18" version I made out of 'gator board' and used at the Okie-Tex star party. See the picture of the mask in #2652853. The gator board is similar to corrugated cardboard, but waterproof. Harder to cut straight edges in it though. Even though the edges were a little rippled this was the result. Joe.
-------------------- JMI 18" f4.5 Newtonian, split ring mount
10" f4.5 Newtonian on GEM (was a DS-10 once upon a time)
50 and 110 mm Mamiya RZ lenses with homemade adapter
ST-2000XM camera