How does Tom Egan's sundial work? It reflects light inside without distorting its original direction:
a novel indoor sundial using an externally mounted convex mirror to compress the entire visual arc of the sky down to the size of the mirror. A pinhole in a mask on the window acts as a camera obscura, projecting the image of the sun onto an indoor dial face that can be as small as a letter-size piece of paper. The system has four parts: A convex mirror mounted just above the roof line; a pinhole lens affixed to the window; and two paired flat mirrors to relay the sun beam from the convex mirror through the pinhole and onto the dial face inside the building.
Another indoor sundial can be seen at www.spectrasundial.com - and you can get one of your very own if you like it!
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