Sundial Altitude Ring Pendant

This type of sundial was invented by Pedro Nunes around 1573 in Portugal. The instrument consists simply of a ring that can be suspended vertically, with a small aperature in the body of the ring. The small hole is positioned to face the sun, and beam of sinlight shines through the hole to land on the interior scale of the ring. This spot of light will land on or between the hour lines on the scale, thus indicating the time.
This fine reproduction is made of cast metal with an antique bronze finish and suspended on a soft red necklace cord with clasp.
The altitude sundial ring ships in a lovely gift box, and comes with a pamphlet which details its history and how to use it.
This model is It is keyed for 50' latitude.