Mac and all, The indication of the equation of time on a mechanical timepiece is usually done with a "kidney piece" which is basically an analemma shape.
It looks like this: http://www.europastar.com/europastar/photos/05_2006/Blancpain3.jpg The kidney piece is at the right foreground in this photo: http://people.timezone.com/staff/EquationOfTime/calibre_2120_2808_005.jpg Here is an illustrated discussion: http://people.timezone.com/staff/EquationOfTime/calibre_2120_2808_005.jpg Bob -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mac Oglesby Sent: Monday, August 04, 2008 6:33 AM To: Sundial Mailing List Subject: Re: Equazione del Tempo Dear Frank, Thanks for posting the photo of this interesting and attractive time and EoT pairing. I wonder if any of the clock experts on the list would care to comment on the mechanism that drives the EoT dial. Does anyone have pictures of the "works" to share? Best wishes, Mac Oglesby >Dear All, > >Next to a sundial it is quite common to see a representation of the >Equation of Time. > >One reason for this is so that people can note the time shown on the >dial and then calculate the time that should be shown on a clock. > >There is an implicit assumption that clock time is what the user really >wants to know and that sundial time is somehow inferior. > >In Italy they think the other way round... > >Take a look at: > > http://www.cl.cam.ac.uk/users/fhk1/EofT.jpg > >Here you will see an ordinary public clock showing 12:51 and >immediately below the clock is a second clock with a single hand that >indicates the EQUAZIONE DEL TEMPO. In the photograph it shows -6 >minutes. > >Here people can note the time on the clock and calculate the time that >should be shown on a sundial! > >The implicit assumption is that sundial time is what the user really >wants to know and that clock time is somehow inferior. > >Bravo to the Italians! > >The photograph was taken on 1 August when the Equation of Time was >indeed about -6 minutes. >The main clock was showing Central European Summer Time. > >I do not know of a public (outdoor) clock in the U.K. that shows the >Equation of Time and wonder how much demand there would be for such a >facililty? > >For completeness: the photograph was taken in Piazza Dante in Naples. > >Frank King >Cambridge, U.K. > >--------------------------------------------------- >https://lists.uni-koeln.de/mailman/listinfo/sundial --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
