Google Images of the entire dial:
Sundial <https://www.google.com/search?q=sundial+Paternoster+Square&rlz=1T4GUEA_enUS 645US645&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjTl76N6p3OAhXDth4KHQhzCKsQ_AUI CigD&biw=1360&bih=737%23imgrc=GnA4srINrL09cM%3A> Paternoster Square -----Original Message----- From: sundial [mailto:[email protected]] On Behalf Of Frank King Sent: Sunday, July 31, 2016 9:23 AM To: [email protected] Subject: Re: Sawyer Dialing Prize 2016 Dear All, I add my congratulations to Roger Bailey and note that he generously refers to my article on "Sundials and Leap Years" in the BSS Bulletin of December 2011. Bob Kellogg referred to this in one of his excellent "Sundials for Starters" pieces: "Bisextile Years and the Analemma" in the NASS Compendium of December 2014. Roger refers to the noon mark at 10 Paternoster Square in London. This is indeed its correct address but the building is, perhaps, better known at the New London Stock Exchange! Each day for two minutes before and two minutes after LOCAL MEAN NOON, the spot of light from an aperture nodus runs along A NARROW STRIP which is associated with THE DAY'S DATE. Most readers will instantly appreciate that 2+2 minutes of time equates to 1 degree of hour angle. Paternoster Square is just under 6 arc minutes WEST of the Greenwich Meridian which equates to just under 24 seconds of time. GMT is marked by an analemma-within-an-analemma. The inner analemma is marked by the vertices of little triangular appendages. A log of the position of the spot as it crosses a strip is therefore as follows, with all times in GMT: 11:58:24 crosses left-hand side 12:00:00 crosses inner analemma 12:00:24 crosses centreline 12:02:24 crosses right-hand side Note 12:00:24 is local mean noon. There is an extra-specially-thin strip for 29 February; this is just under a quarter the width of its neighbours (reflecting the fact that the tropical year is just under 365 and a quarter days). The spot of light runs along this strip only in leap years. In common years it runs along the 28 February strip one day and the 1 March strip the next day, skiping the 29 February strip. Since the noon mark was put up, there have been 4 instances of 29 February... 2004 It was snowing hard 2008 It was raining hard 2012 There was 100% cloud cover 2016 Clear Sky!! Hurrah! Now look at: http://www.cl.cam.ac.uk/users/fhk1/Sundials/NoonGMT29Feb.jpg You will see the appearance of the spot of light:: on 2016-02-29 at 12:00:00 GMT This photograph is hereby published for the first time. No one else has ever seen this. I was the only person looking at the Stock Exchange at the critical moment. YOU SAW IT HERE FIRST!! The mathematics is not too challenging. The surveying was horrendously difficult!! Engineering is harder than mathematics! Frank Frank H. King Cambridge, U.K. --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
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