To all sundialists, All that stuff is the result of the irresistible urge to let indicate the time of a watch by a sundial. A sundial is intended to indicate the solar time. It is the only simple instrument that can do it. In order to indicate the artificial time, which we have created to practical reasons, we have a watch and many other devices. Tell the people that our watch gains or loses compared to the real natural time and that a sundial indicates this natural time, a watch the artificial time.
And use your knowledge of mathematics for more useful purposes! Willy Leenders Hasselt in Flanders (Belgium) Visit my website about the sundials in the province of Limburg (Flanders) with a section 'worth knowing about sundials' (mostly in Dutch): http://www.wijzerweb.be Op 17-aug-2016, om 19:51 heeft fabio.savian het volgende geschreven: > > thank you Willy and Fred for your notes, > > I know an analemmatic sundial may have sophisticated versions to show mean > time, Fred your article is exhaustive, but I think it isn't the better kind > of sundial to give this info and to get a precison time (position on the > heels or on the middle of the feet, how vertical is the hand rising above the > head, estimation of the direction of the shadow, graduations of the minutes, > etc). Conversely it is a very powerful instrument to involve people with > gnomonics. > > Anyway I think a simple analemma on the meridian line, without explain its > huge limits, is not an option, it is an error. > > thank you, ciao, Fabio > > Fabio Savian > > > > Inviato da Tablet Samsung. > > > -------- Messaggio originale -------- > Da: Fred Sawyer <[email protected]> > Data: 16/08/2016 20:37 (GMT+02:00) > A: "fabio.savian" <[email protected]> > Cc: Sundial Group <[email protected]> > Oggetto: Re: Double analemma dials > > Hi Fabio > > This use of an analemma design on the analemmatic dial has been a confusing > error that goes back at least to the early 20th century introduction of the > curve on the dial in Brou, France. The use of a double analemma design with > curves calculated to limit error to just a few minutes throughout the year > goes back at least to 1970 and the work of Ken Seidelman at Longwood Gardens > in Pennsylvania. For a detailed discussion with equations, etc. see my > article "Of Analemmas, Mean Time and the Analemmatic Sundial" that you can > download at https://dl.dropboxusercontent.com/u/4837615/scia7.pdf Brian > Albinson has taken this idea to heart and, using a slightly different > approach to the equations, has designed several such dials in the Vancouver > area. > > Fred Sawyer > > On Tue, Aug 16, 2016 at 12:23 PM, fabio.savian <[email protected]> > wrote: > > hi all, > > I draw inspiration from the image sent by Brian Albison for a meditation. > > I often found analemmatic sundials with the analemma. Has it a sense ? > > Standing on the analemma one can get the right correction for eot only at > noon. > Most of these sundials don't report a warning about it, so the users get a > wrong time al the day, except noon. > Moreover some of them haven't the calendar on the meridian line but only on > the analemma, so the misunderstanding is sure. > > The use of a table with the eot should solve the curiosity to get the mean > time, so I wonder why this kind of sundial is knowspreading with the analemma > while it is not suitable for this. > Do you where this use come from ? > > ciao Fabio > > Fabio Savian > > Inviato da Tablet Samsung. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -------- Messaggio originale -------- > Da: Brian Albinson <[email protected]> > Data: 16/08/2016 18:04 (GMT+02:00) > A: Sundial Group <[email protected]> > Oggetto: Double analemma dials > > Hi folk > > We have built 3 direct reading mean time double analemma dials, > (including the Highlands School dial) in the Vancouver area and are > curious to know if any others exist in the world (apart from the > Longwood dial). > > Brian Albinson > > Len Berggren > > Vancouver, Canada > > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > > > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial >
--------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
