A rare and extremely unusual map shows the world projected from the North Pole as if it were the table of a sundial. Although at first glance it appears as if the landmasses are melting off the earth, they are actually drawn to scale based on a mathematical projection that links time and location. Ritter uses a gnomonic projection, in which surface points of a sphere are projected from the center of the earth onto a tangent plane. Meridians and the Equator are shown as straight lines, while all other parallels are depicted as ellipsis, parabolas or hyperbolas. In order to use the map to tell time, the center point would be 45°N 10°E, from which point a shadow would be cast onto a meridian to indicate the local sun time. The gnomonic projection was originally called horologium due to its relationship to sundials.
The result is a very distorted, though mathematically correct, projection, with the distortion increasing rapidly away from the center point. The geography on the map is limited to major rivers and a few place names, including Florida in North America and the fabled golden city of Manoa on the mythical Parime Lacus in South America. The British Isles are curiously omitted, despite numerous small islands dotting the Atlantic. One small sea monster graces the waters between Africa and Madagascar.
Surrounding the central map are ten horological diagrams, all enclosed in a decorative border. These diagrams include a windrose at top center (bearing the date Anno MDCVII), signs of the zodiac, and sundials for morning, midday and evening hours. The plate was designed for Ritter's first edition of the Speculum Solis in 1607, and is a synopsis of all the plates that appear in his later editions. This is the first state.
References: cf. Shirley #270.
A dark impression on paper with the watermark of a small medallion with two crosses, issued folding and now flattened. There is light printer's ink residue, a minor printer's crease at bottom center, and marginal soiling. The margins have been professionally extended all the way around the map to accommodate framing.