Willy, In the past local suntime was used for civil time. A sundial was the leading instrument.
When a clock was placed on the church the clock was regulated by the parish clerk to local suntime with the help of a sundial. This is why we often see a clock and a sundial on one building. As people got their clock at home a table for the EoT was delivered with it so they could regulate the clock at home for local suntime. Some clocks had the EoT correction build in to keep it running local suntime. If I follow this story it isn't strange to me to see the combination of a clock with a second mechanical dial for the EoT, however, a build in correction would have been easier in use. Sounds this reasonable? Best wishes, Fer. Fer J. de Vries De Zonnewijzerkring http://www.de-zonnewijzerkring.nl Molens http://www.collsemolen.dse.nl Eindhoven, Netherlands lat. 51:30 N long. 5:30 E ----- Original Message ----- From: Willy Leenders To: Frank King Cc: sundial Sent: Monday, August 04, 2008 6:37 PM Subject: Re: Equazione del Tempo What is the importance for an ordinary citizen to have an indication of EOT nearby a clock that indicates civil time? He does not know what this is and if he wants to know the time as a sundial indicates, he has to calculate and he should also bring in account the time difference by the difference in longitude and the summertime. Would it not be better to design a clock that indicates immediately the 'sundial time'? Willy LEENDERS Hasselt in Flanders (Belgium) www.wijzerweb.be Op 4-aug-08, om 11:06 heeft Frank King het volgende geschreven: 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
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