Hello Paul and all, Size doesn't matter. It is how you use your tool that is important. The shadows from people as gnomons are only so long. What is the use of an instrument when the indicator does not reach the scale? My NASS presentation "How Long is My Shadow" discusses this issue and offers a spreadsheet to calculate shadow lengths. See presentation http://www.walkingshadow.info/Publications/How%20Long.pdf The logic is now better expressed in "Helmut Sonderegger's "Alemma" program. See http://www.helson.at/sun.htm Typically 5 m is a good size for an analemmatic sundial with a human gnomon.
There is a larger analemmatic sundial In Penticton British Columbia, Canada. Here is a link to the NASS registry.. http://sundials.org/index.php/component/sundials/onedial/240 This Penticton dial is 10.7 m x 19.8 m. It is a BIG sundial and can be seen with Google Earth at 49°27.189' N, 119°34.972' W. Although it was built in 1984 by a well known sculptor with design advice from a professional astronomer, it is a poor design for many reasons. It is too big. The shadows fall well short of the hour posts. The large posts marking the solstices and equinox are displaced from the date line. It has an analemma shape marked with the dates to correct for the equation of time. This correction is popular but it does not work except at noon. The original sundial was made of wood and quickly rotted away on this exposed sandy beach. The current model using concrete may last longer. However it is an attractive popular feature on the beach in Penticton. Hopefully some using the dial will have the curiosity of a three year old and ask "Why" and remain curious after the typical adult response, "Because, that is the way it is". Sundials taught me to ask "Why" and seek answers beyond "Because". Regards, Roger Bailey Walking Shadow Designs From: Sunclocks North America Sent: Tuesday, June 18, 2013 6:26 PM To: Sundial Mailing List Subject: Re: A big new analemmatic sundial on Malta Hello All, Congratulations to Mr. David Grima and to Stella Maris College for their accomplishment in building a beautiful Human Sundial, which is very nice and constructed with great looking materials and decorations. I would like to point out, however, that it is not the world's largest sundial, as the timesofmalta.com article has indicated, although it may be the worlds largest sundial 'made out of volcanic stone', as Mr. Grima was careful to point out in the video. There is at least one Human Sundial that I know of, located at 'Chatsworth House' in the UK that has a diameter of eight meters, or one meter larger than the Malta sundial. In addition, the Chatsworth House Human Sundial is of a "SunClock" style that is corrected to indicate clock time instead of Sun Time, and which is also set-up to automatically adjust for Daylight Saving Time. Thank you, Paul Ratto SunClocks North America 438-792-4823 On 2013-06-12, at 9:46 AM, Perit Alexei Pace <[email protected]> wrote: Hello Jim, Thank you for your email, It was great working on this project (I made the calculations and concept design), which will hopefully help many students appreciate the beauty of science and art. Best regards, Alexei Malta On 12 June 2013 14:23, J. Tallman <[email protected]> wrote: Hello All, Here is an interesting link to a video/story about a new analemmatic sundial installation on Malta – it seems that the dial type continues to spread, especially at schools, and this is a really nice one! http://www.timesofmalta.com/articles/view/20130611/local/School-awaits-sundial-that-will-last-a-century.473347 Best, Jim Tallman www.spectrasundial.com www.artisanindustrials.com [email protected] 513-253-5497 --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial -------------------------------------------------------------------------------- --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial -------------------------------------------------------------------------------- No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.3345 / Virus Database: 3199/6422 - Release Date: 06/18/13 ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.3345 / Virus Database: 3199/6422 - Release Date: 06/18/13
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