A Lens for the Observatory

I carried my clear glass marble over to the upside-down terracotta pot on the sunny patio bricks! Fluttering my twin tails to hop onto the circular base, I carefully seated the sphere directly over the centered drainage hole. The curved glass fit neatly into the clay bevel without slipping through. Crouching low on the warm rim, I shaded my eyes with one glove and peered straight down through the glass into the pot's dark interior. The sun focused right through that internal sapphire ribbon, throwing a brilliant, shimmering blue spotlight onto the shaded bricks below! My garden observatory now has a real working optical condenser.