Geoff, If you measure the time in true local time (solar time), as I do, the EoT is not relevant.
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 14-jun-2016, om 15:51 heeft Geoff Thurston het volgende geschreven: > Thanks for the mental exercise, Frank. I think that Willy might squeeze > another 15 seconds of illumination at the end of December owing to the rapid > change in the EoT. A useful graph showing the rate of change of EoT is > provided by the USNO at: > > http://aa.usno.navy.mil/faq/docs/eqtime.php > > Geoff Thurston > > On 14 June 2016 at 13:01, Willy Leenders <[email protected]> wrote: > > See on my website: http://www.wijzerweb.be/analemmatischengels.html > The maximum time (12 hours) of sunlight on a vertical wall of any direction > is above the Arctic Circle on a day when the midnight sun shines > > 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 14-jun-2016, om 10:29 heeft Frank King het volgende geschreven: > >> Dear Dan, >> >> The approach that you describe does >> indeed show you how long the sun can >> theoretically shine on a vertical >> wall, for a given solar declination, >> provided (as you say) that you know >> the times the sun rises and sets. >> >> Now a simple exercise... >> >> What is the maximum amount of time >> the sun can shine on a vertical wall? >> >> You can choose the latitude and you >> can choose the orientation of the >> wall and you can choose the solar >> declination. >> >> 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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