Hi everyone, I mostly agree with Roger that size doesn't matter, but only in general terms when talking about human sundials. I feel that overly large analemmatic sundials are not really suitable to be effective Human Sundials, human sized gnomon's simply being too small to reach the hour markers. Conversely, if the sundial is too small, then a human sized shadow will tend to overwhelm the hour markers. However, I am nevertheless not surprised by the popularity of the Penticton sundial because the interactive aspect of Human Sundials generally tend to make them very popular wherever they may be.
In addition, analemmatic sundials have the added problem of shadows being too long in the winter and too short in the summer, which is why I like the distinctive design of "SunClock" style Human Sundials which is designed with two rings of hour markers - one for the shorter shadows of 'summer' time, and the other for the longer shadows of 'winter' time. In addition to the added accuracy that this brings, along with being adjusted for clock time as opposed to sun time, I am personally of the opinion that this "double ring" design is actually more aesthetically pleasing than a regular single ring design. If you're interested in knowing more about "SunClock" Human Sundials, you can learn more by visiting http://www.sunclocks.com. Thanks, Paul Ratto SunClocks North America 438-792-4823 On 2013-06-18, at 23:19, Roger Bailey <[email protected]> wrote: > 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 >
--------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
