An Unusual World Map with Signs of the Zodiac
Scarce pair of hemisphere maps on two separate sheets, topped with the signs of the Zodiac, published by Johannes Zahn in Nuremberg.
California is shown as an Island on the Briggs model, with a flat northern coastline. The Straet Anian is shown, hinting at a Northwest Passage. The Southern Hemisphere reflects the explorations of the Dutch, most notably the partial coastlines for Australia and New Zealand, as first depicted by Abel Tasman in the 1640s.
Zahn abandons the fictitious representations of the unknown southern continent (Terra Australis Incognita) for a more clean scientific depiction of the known world.
The surrounding decorations are presented in an unique and original manner with a broad zodiacal band at the top of each hemisphere, and the bottom corners filled with graceful female representations of the four seasons and cherubs representing the four elements.
The work appeared in Johannes Zahn's Specula Physico-Mathematico-Historica Notabilium…. Zahn was best known for his work on optics, including astronomical observation. A student of the astronomer Franz Griendel von Ach from Nuremberg, Zahn was a professor of mathematics at the University of Würzburg.
Zahn developed the SLR camera with an upright image (deflection mirror), developed by Johann Sturm in 1676, by placing a telescopic lens made of two parts (convex and concave) with different focal lengths in succession, so that a larger image was created ( reflex camera obscura ). He also painted the exposure chamber black to prevent reflections. In 1686, he constructed a portable camera obscura. A mirror, which was installed at an angle of 45 degrees to the lens inside the camera, projected the image upwards onto a focusing screen, where it could be easily drawn. The image could be brought into focus with a rectangular extract.
His work Specula physico - mathematico - historica notabilium was a summary of all natural sciences.