Hi John, Thanks for passing on the photo of the laser "sundial." Compared with this artificial dial, my annosphere more closely mimics the gnomon's shadow for the set latitude, as the hour lines do not spread evenly (except at the north pole.)
My "dial" also shows the length of day. The time at which LED/sun passes above and below the edge of the disk changes every day, so that in the summer days are longer than they are in the winter. Thanks again for your interest, and for all the help you provide to list posters. John On Sep 29, 2009, at 12:12 PM, John Carmichael wrote: > > Thanks for sharing that John G. > > Here is another mechanical indoor 'sundial' using a laser. > > http://www.flickr.com/photos/5volt/3260213536/in/pool-1207...@n23 > > Best always! > > John C. > > -----Original Message----- > From: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni- > koeln.de] On > Behalf Of John Goodman > Sent: Tuesday, September 29, 2009 8:48 AM > To: sundial@uni-koeln.de > Subject: Re: Another mechanical sundial > > Dear dialists, > > While we're stretching the definition of a sundial, I'll pass on a > link to my version of a mechanical sundial that I call an annosphere. > > The annosphere uses a set of gears to create a day-to-year ratio of 1 > to 365.2422. A ring, inclined at the angle of the ecliptic, turns once > a year around a disk rotating once a day. > > Riding on the inclined ring and shining on the disk, an LED rises and > falls over the course of a year. The rising and falling LED/sun > changes the duration of daylight on the disk. A gnomon centered on the > disk casts a shadow indicating the time. > > The disk can be angled to match any latitude in the northern > hemisphere. This "sundial" shows clock time, with no simulation of the > variations normally accounted for with the EoT. > > I apologize for my confusing explanation. If you'd like a better > understanding, please take a look at the photos on the website > http://annosphere.com > An animated demonstration of the gearing is shown at > http://annosphere.com/demo > > Please note that the demo is interactive and, unfortunately, it can't > work without installing a few plug-ins. Your browser will prompt you > for permission, which you can refuse, but the demo will not run > without them. > > I knew next to nothing about sundials when I began this project (and I > still know very little.) I joined this list to learn more and, even > with my annosphere completed, I continue to enjoy the discussion and > education that takes place here. > > Thank you for regularly sharing your knowledge. > John > > > P.S. > Eduardo Catalano, the creator of the sun sculpture mentioned > previously by John Carmichael, used to practice architecture just a > few blocks from where I live. > > >> Date: Mon, 28 Sep 2009 11:58:40 -0700 >> From: "John Carmichael" <jlcarmich...@comcast.net> >> Subject: Another mechanical sundial >> >> Hi Robert & others: >> >> >> Somewhat distantly related to this subject is this other type >> mechanical >> "sundial". >> >> >> It is called the Floralis Generica, a huge metal flower made by >> Eduardo >> Catalano, an argentinian artist who was born in 1917. It was a gift >> from the >> artist to Buenos Aires. The structure of the flower is made of >> steel and >> the shiny panels in the petals are made of aluminium. The sculpture >> moves, >> closing its petals at night and opening them during the day. The >> sculpture >> is the work of Argentinian architect Eduardo Catalano, who also was a >> Professor Emeritus at MIT. >> >> >> http://www.flickr.com/groups/floralisgenerica/pool/ >> >> >> John > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
