Hi David/Susan: By the fact that none of the experts on the list know of a traditional name to call this type of time, I guess everyone is free to use his own terminology. In all my sundial literature, I have been unable to find any reference to the name of this type of time. Your definition: "Zonal Apparent Time" is almost identical to the one preposed by Ciao Gianni who suggested the term: "Time-Zone True Time".
I'd like to use your definition in my "Sundial Owner's Manual", if it's ok with you? Thanks for your detailed and thought out answer. John Carmichael http://www.azstarnet.con >Hello all: >Having been away for the week of (US) Labor Day, I return to a mailbox full of >interesting items. Not being a sundial constructor, but having had interest in the >math and such topics may I address this question? > >I suggest the phrase Zonal Apparent Time. >My reasoning: The sun (ie, true sun; the thing up there; hence time on a >sundial) identifies Local Apparent Time (referred to by some as Local True Time, >since it is the true sun.) Correcting for longitude provides the Apparent Time at >the Meridian of the time zone. That is what a sundial would read at that place. > >The EOT "changes" the Apparent Time defined by the True Sun to the Mean Time of >the (fictitious ) mean sun. It is the mean sun which provides for 24 hours per day >. The true sun is "off" this arbitrary standard by the amount of the EOT. > >Eg: I am at 118º W. My zone is defined as 8 hours slow on GMT hence by the >Meridian at 120º W >If my sundial reads noon, then it is 1200 hrs LAT; when it is noon at 120º W's >dial , my dial reads 1152 hrs. Notice that NO clock will read these times unless >the EOT is 0 for that day. Clocks refer to the fictitious Mean Sun. > >Hope that helps. I am using 19th Century simple definitions of course without >reference to Ephemeris Time, UT, UT(0), UT(1) or Atomic Time. > >DAVE >33º 39' N 118º 05' W ..........by my own sights and subject to >change :) > >John Carmichael wrote: > >> Hello all: >> >> I've got a little simple question that I'm not quite sure how to answer. >> >> What would be the correct definition of the type of time shown by a sundial >> which is longitudinally corrected, but NOT corrected for The Equation Of Time? >> >> Thanks so much, >> >> John Carmichael >> http://www.azstarnet.com/~pappas >> >> p.s. Tony Moss said that he had a problem logging onto my website. Would any >> of you living in Great Britain mind checking to see if you too are having >> trouble? > >
