Hi Tony and all, I believe there is a simple answer. Look at the latitude, about 40 degrees. Anyone wanting to market sundials in America would choose 40 degrees latitude as the standard. This captures the population centre of America. Ignore the latitude. Correcting for latitude is not usually done. Nor is an EQT correction important. Local solar time rules. No one expects sundials to be accurate!
My nomination for the standard is Philadelphia PA at Lat 40 and Long 75. It meets the American standard and is right on the eastern time zone centre. Manufacture your dials for Philadelphia and the American market is yours. Cheers, Roger Bailey Walking Shadow Designs N 51 which is pretty close to the World Standard of Greenwich W 115 which is way off our local time zone centred on 105 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Tony Moss Sent: September 18, 2002 2:52 PM To: Sundial Mail List Subject: Query Subject: Repeat posting Sent: 17/9/02 1:21 PM To: Sundial Mail List, sundial@rrz.uni-koeln.de Fellow Shadow watchers, Apologies if you've seen this more than once - if at all - but for some reason I didn't receive a circulated version via the SML so have assumed it has gone astray. Tony Moss ******************************************** Subject: USA Help reqired! Sent: 16/9/02 11:59 PM To: Sundial Mail List, sundial@rrz.uni-koeln.de Hi US Shadow Watchers. I have a US client who contributed the following and then asked me what the truth of the matter is - if anything? >"....but the arcane bit of knowledge I had never heard before was that the man >(name forgotten) who studied and then defined the "line" from which all North >American sundials are "calibrated" (if that is the word) had established that >geographic point in this city of Indianapolis." >From this side of the ocean Indianapolis, with due respect, looks like an unlikely candidate for any longitudinal distinction. My 'Times' Atlas tells me that it lies at 39° 45' North and 86° 10' West which logically would seem to put it in the Central timezone (Reference Meridian 90° West) but my British Admiralty World Time Zone Chart seems to locate it in Eastern Time where the reference meridian is 75° West so that hardly suggests anything very clearcut. Of course it could be a reference to something/someone much earlier before transcontinental railways and timezones. Any thoughts which might illuminate this? Best wishes Tony Moss - -
