Hi, I changed the heading because at first I got to thinking about that sundial on Mars....
Yes, there are quite a few sundials that were designed especially for their seaworthiness and other timefinding instruments that were readily adapted for maritime use. The first that comes to mind is the universal ring dial (URD), which being suspended from a shackle and self-orienting, was a featured instrument in numerous manuals written for seaman from the mid-17th century onward. The large examples for sea use have a nautical quadrant on the back for finding latitude by the sun at noon. While the familiar form was invented by William Oughtred in the early 17th century, the URD was related to the astronomical ring of Gemma Frisius of a century earlier. This appears on the inventories for Martin Frobisher's and Sir Humphrey Gilbert's voyages (respectivally 1576 and 1583) along with a self-orienting universal sundial. An azimuth compass is also listed on the inventories. This is essentially a horizontal sundial mounted on a mariner's compass, and so moves on gimbals. It could be used to find time and check the sun's azimuth. Other timefinding instruments that went to sea are the planispheric astrolabe (but rarely), the astrolabe quadrant (one form is the Gunter's quadrant), and the nocturnal (for use at night). Cheers, Sara Lat 42.4N Long -71.1W On 10/13/2007 10:16 AM, J. Tallman wrote: > Hello All, > > Has anyone ever seen a sundial specifically designed for use on a boat > or ship? > > I realize that there are obvious issues re: movement and variable > location, but I thought it might be an interesting question for the list > to consider from the historical perspective... > > > Best, > > Jim Tallman > www.artisanindustrials.com > [EMAIL PROTECTED] > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > -- Sara Schechner, Ph.D. David P. Wheatland Curator Collection of Historical Scientific Instruments Department of the History of Science Harvard University, Science Center 251c 1 Oxford Street, Cambridge, MA 02138 Tel: 617-496-9542 Fax: 617-496-5932 --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
