Solar Eclipse 2026: A cereal box can be turned into a simple solar eclipse viewer using a few household items. Solar Eclipse 2026: What Is A Cereal Box Eclipse Viewer? A cereal box eclipse viewer is a homemade pinhole projector that creates a small image of the Sun inside a cereal box. Solar Eclipse 2026: How To Make A Cereal Box Eclipse Viewer? Why A Cereal Box Viewer WorksThe cereal box viewer works on the principle of pinhole projection.