Fer de Vries passed away
Dear all, I deeply regret to inform you that Fer de Vries, honorary member of the Dutch Sundial Society, passed away on April 1, at the age of 78. The funeral service was held today privately. He suffered from a stroke two years ago, from which he only partially recovered. He was a pivotal member of our society, which he joined right after its birth in 1978. He served as treasurer for 9 years and as secretary for another 19 years. In the meantime, he contributed some 200 articles to our Bulletin. Many of you have known him, or at least his work, among which were important contributions to the science of gnomonics. His software ZW2000, which he freely made available to the international sundialling community, was used by many. He cooperated with many sundialists abroad. He won the first Sawyer Dialing Prize in 2000. We lose a generous, devoted, enthousiastic and productive person and diallist. If you would like to contact his family directly, the address for correspondence is: Stationsweg 136 5611 BZ Eindhoven The Netherlands On behalf of the Dutch Sundial Society, Frans Maes, secretary --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Rare sundial book query
David, See: www.amazon.co.uk/exec/obidos/ASIN/B009NMD7T2/ref=nosim/1557 Best regards, Frans Maes On 10-11-2014 17:19, David wrote: /Hebrew and Greek Scriptures compared with Oriental History/ --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: a unique sundial on a cylindrical column of opal glass
Dear Helmut all, I don't think Woody Sullivan's sundial is very similar to Willy Leenders' impressive sundial. From a typological point of view, Sullivan's sundial is a shepherd dial. It uses the altitude of the sun to show the time. Willy Leenders' dial is a nodal dial, similar to a scaphe dial or a chalice dial. It derives the time from the sun's hour angle. Best regards, Frans Maes On 14-10-2013 15:17, Helmut Sonderegger (Tele2) wrote: Hi Roderick, I like Willys new sundial too. It looks beautifully. I included this sundial construction a longer time ago in my software SONNE and discussed different cylinder sundials in Compendium vol 16 nr. 4 (Dec 2009). In my freeware Sonne.exe you can construct the sundial for the outside of a cylinder with fixed orientation and moveable horizontal gnomon (see image below). Now Willy has positioned the Gnomon in the central axis of the cylinder and so the gnomon length is equal the radius and nee not be turned around. The construction stays the same but the scale is positioned on the Northern part of the vertical cylinder instead of South. By the way: Woody Sulllivan made a very similar construction on the outer side of a cone ( http://sundials.org/index.php/component/sundials/onedial/746 ) Helmut Sonderegger www.helson.at --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Interesting sundial
Hi Roderick, Was it perhaps an Erickson Polar Equatorial Dial that you had in mind? See one example in Denver, Colorado, at: www.wsanford.com/~wsanford/exo/sundials/co/denver/cranmer/index.html The NASS registry lists about 12 dials of this type. Best regards, Frans Maes On 26-1-2013 4:50, R Wall ml wrote: Hi all, That reminds me, I do remember seeing somewhere a photo of a stone disk sundial. With a steel pole through the stone disk that also held the disk at the correct angle. Think it was a Chinese sundial. Now where did I see that? Roderick Wall. From: Dave Bell Sent: Saturday, January 26, 2013 1:38 PM To: 'Douglas Vogt' ; sundial@uni-koeln.de Subject: RE: Interesting sundial I’m sure Tony Moss would be happy to explain it, Douglas! In short, it’s an Equatorial dial, as I recall. The dial plane is parallel to the Earth’s equator, and the little stubs of gnomons are parallel to the Earth’s axis. One face is illuminated in the Summer, the other in Winter. Dave From: sundial [mailto:sundial-boun...@uni-koeln.de] On Behalf Of Douglas Vogt Sent: Friday, January 25, 2013 10:31 AM To: sundial@uni-koeln.de Subject: Interesting sundial In a previous post (24 Jan. 2013), I thought a sundial in a photo was neat and wondered if there were plans for it. As a relative newcomer, I don't even know what kind it is. That post was apparently completely misinterpreted by an irritable being as something having to do more with those things that run on steel rails and not sundials. I merely responded to the subject line. My post and the response caused further OTs, for which I apologize. In any case, it is a neat sundial and I'd like to know more about it if the designer is not too P.O.d to respond. From: John Carmichael jlcarmich...@comcast.net To: 'jim senato' j...@kcpc.com; sundial@uni-koeln.de Sent: Friday, January 25, 2013 12:32 AM Subject: RE: sundial Digest, Vol 85, Issue 28 Hello Mr. Senato: Do we know you? I searched my inbox archive and see that you have only written one letter previously to the Sundial List back in 2011. In that letter you talk about FED EX and not sundials. See copy of your letter below. Let me respectfully clue you in on a few things… I have been on this mailing list for about 15 years I think, and as far as I know, there is no rule that we must only respond to the “subject at hand”. If this were the case, then no new subjects would ever appear. Often, several sundial-related subjects are discussed on the same day. However, since it is the Sundial List, most of us do try to limit our subjects to sundial related matter. My last letter was obviously about a sundial (a famous one by Tony Moss at that), and it included the best existing photos of that sundial as well as a photo of one of America’s only stained glass sundials. It was NOT about a “train set”. I don’t think I broke any Sundial List rules, and lots of people wrote to tell me they liked seeing the sundial photographs. The courteous thing for you to do would be to simply ignore letters that don’t interest you. We all do that. But none of us EVER tells anyone on the list to shut up. How rude was that! Think before you type. Sincerely, “that guy” p.s. You might want to do a grammar and spelling check on your letters before you send them. I’d be embarrassed if I were you. They make you look ignorant and uneducated. Letter from Jim Senato sent on 10/29/1011 let these people know to call fedex next time why would you actually go as far as filling out a form call if you arent surewouldnt you know if you were tracking a package without filling out somethingtell them to use some common sense this is not a big threat --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Simple, inexpensive sundials
Hi John, You might have a look at: - Astrovisuals' sun disk: http://www.astrovisuals.com.au/SunDisc.html - Astromedia: http://www.astromedia.de/. They have several sundial types. The site is in German; just remember that sundial = Sonnenuhr. Not for continuous outside placement. Best regards, Frans Maes On 28-8-2011 1:27, John Goodman wrote: From time to time, list subscribers have posted links to low-cost, simple sundials. I'm helping a friend find a source for time-related gifts priced at less than $25. Can anyone please refer me to sundials that meet those price guidelines? Thanks very much, John --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Please may we have our sundial mailing list back
I agree completely! Frans Maes On 14-8-2011 11:43, Geoffrey Thurston wrote: I have been an avid reader of and an occasional contributor to this list for many years but I am concerned about its present state of health. It has previously been customary for contributors to make a posting (a question, an answer or a comment) only when they could make a useful contribution to a discussion related to sundials and this custom has served to maintain the interest and good humour of our debate. Unfortunately, over the last few weeks we have been subjected to a flurry of trivial postings which have resulted in a public resignation, caused offence to readers and led to rancorous postings. I believe it would be healthier for this valuable forum if we reverted to a system of more considered postings and left the instant exchange of banalities to Twitter and Facebook where they belong. Please take care with the Sundial Mailing List. It is too good to lose. Geoff --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: sundial read from moonlight
Dear Donald, One can use the moon's shadow as long as it is distinguishable at night, say, one week either side of full moon. For an example, see: http://www.fransmaes.nl/genk/welcome-e.htm, choose menu item 7 and scroll down in the right-hand frame to The moon dial. Best regards, Frans Maes On 30-7-2011 10:23, Donald Christensen wrote: I heard that a sundial will read the correct time with the shadow on the moon on a certain day. (full moon?) --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: sundial /Jacopo de'Benci
I also agree, also as a mock HORIZONTAL dial. The intended latitude Phi should be related to the angle A between the 12 and 9 (or 3) hr lines as: sin(Phi) = tan (A). [For a vertical direct south dial, change sin into cos.] As A is clearly more than 45°, tan(A)1, which is beyond the reach of the sin as well as the cos function. Best regards, Frans Maes On 1-6-2011 5:38, Roger Bailey wrote: I agree with John and Jack, this dial is suffering from gnomon dysfunction. This affects a lot of older sundials. The intended gnomon was polar, not normal (perpendicular).. Jack analyzed the hour lines and found that they are inconsistent. I did similar limited tests and agree. This sundial seems to be a mass produced brass plate item, not an engraved and gnomonically correct sundial. The patterns on the dial are easily mass produced as brass plate pressings. If this were the Antique Road Show I would not place a significant value on this sundial. Some things do not improve with age. Regards, Roger Bailey Walking Shadow Designs From: John Carmichael Sent: Monday, May 30, 2011 7:55 AM To: 'Sundial List' Cc: i...@mediadesign.me Subject: FW: sundial /Jacopo de'Benci Hi Jan- I'm forwarding your letter and my comments to the Sundial List. Perhaps the sundial experts in our group can help you more than I can! ___ Hello Dialists: I received this letter inquiring about an old European sundial. I'm not an expert on these things, so I'm forwarding the letter to you guys. I've never heard of the maker- Jacopo de' Benci whose name is inscribed on the dial. Looking at the enlarged photo of it at http://www.mediadesign.me/pollaiuolo/images/sonnenuhr-jacopo-de-benci-4.jpg you can see it has a perpendicular rod gnomon, implying that at first glance it is a nodus-based design. But the location of the rod seems to be incorrectly located at the convergence of the hour lines. I'm thinking that this dial was not designed to have a perpendicular gnomon. It should have an angled polar axis gnomon (an angled rod or a triangular sheet). Perhaps the rod was added to the original attachment hole after the original polar axis gnomon fell off at an earlier date. Does my analysis seem correct? Please copy your replies to Jan K. Botor at i...@mediadesign.me Thx John C. From: info-mediadesign [mailto:i...@mediadesign.me] Sent: Monday, May 30, 2011 2:45 AM To: jlcarmich...@comcast.net Subject: sundial /Jacopo de'Benci Dear Mr Carmichael. Mrs. Monika Leonhardt, M.A. (Uhrenmuseum Beyer Zürich) kindly provided me with your contact details. I am currently trying to investigate into the origin of this sundial and I kindly ask you for your opinion as an expert about this piece of applied art and your suggestion if it could possibly be authentic. My personal opinion is that it is a copy of something made in the 19th Century but I can not locate anything similar whether in books nor in the whole internet. I put the details that I know, a summary of suggestions I received 3rd hand and high-resolution pictures at the following link: http://www.mediadesign.me/pollaiuolo/index.html It is my intention to give it to an department for dendrochronical and spectroscopic analysis, as I got various information that differs widely regarding the possible age and origin. It is starting with suggestions, placing it around the early 19th century and goes as far as it was possibly an early work by Pollaiuolo at the goldsmith Ghiberti where Jacopo de' Benci was apprentice for Metalwork. That is well a wide range for speculations so, the coming analysis will place the object in a probable timeframe, I hope . I want to thank you in advance for your effort and It would be really nice to hear your opinion and if a scientific analysis would be advisable. If it is of interest, as the photographs are may not sufficient I would be glad to provide you with the original instrument for further research. With kind regards, Jan K. Botor Hauptstr.40 25704 Meldorf T 0178-7732125 i...@mediadesign.me www.mediadesign.me --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: An interesting digital orrery
Hi all, It was fun to reconstruct the state of the solar system on May 8, 1774. Why that date? On that day the moon, Mercurius, Venus, Mars and Jupiter would come together in the sign of Aries. This led to panic, as the cosmos was by many expected to collapse. An amateur astronomer, Eise Eisinga from Franeker (The Netherlands) wanted to show his fellow citizens the real cause of the conjunction and convince them that nothing would happen. He set out to build a planetarium in his living room that showed the Copernican layout of the solar system. The task took him 8 years (too late for the fatal date, that indeed passed smoothly). The planetarium, however, is still with us and is the oldest working planaterium in the world. Recently it was recoginized by UNESCO as a World Heritage Site. See http://www.planetarium-friesland.nl/engels.html. Thanks for the link! Frans Maes On 23-4-2011 18:36, Frederick Jaggi wrote: A company called Dynamic Designs produced this very interesting orrery based on NASA data as a demonstration piece: http://www.dynamicdiagrams.com/work/orrery/ Frederick Jaggi Horas Non Numero Nisi Serenas --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Are there any commercially-available 'Teaching Sundials', for schools ?
Hi Martina, An analemmatic sundial may just be painted onto the pavement of the schoolyard, which should - after drying - take away any safety risks. Otherwise you might have a look at: - the Sun Disk from Astrovisuals, http://www.astrovisuals.com.au/SunDisc.html - the Sundial Science Construction Kit from Science Times, http://www.outtolearn.co.nz/product_info.php?products_id=5304 - the sundials (Sonnenuhren) from Astromedia, http://www.astromedia.de/ Good luck with your project, and let us know about the results and your experiences, positive as well as negative. That will comprise valuable information for many of us on the list! Best regards, Frans Maes www.fransmaes.nl/sundials On 22-4-2011 13:19, Martina Addiscott wrote: Is anyone aware of a commercially-available large 'Teaching Sundial', which would be suitable for fulfilling that part of the UK National Curriculum ? As many of you no doubt know, sundials are included in the Science section of that curriculum, but each school decides for themselves how to cover it. We had originally intended to mark an interactive analemmatic dial on to the playground - but our local Educational Authority will not give us their permission for that, because of the 'health and safety' implications (as basically they feel that such layouts are too dangerous for the children). It had also been suggested to us that a large globe-of-the-world might be a good way to cover the necessary aspects (Latitude/Longitude, daily rotation of the earth, night/day, annual change of seasons, etc) - but we feel that there has to be something better and more 'sundial-specific', if only we can trace suppliers of any suitable item being sold at a reasonable price. Len Honey at Science Replicas suggested an individual portable dial, for each pupil - but (apart from the cost), we think that those would soon get damaged (or simply 'go missing'). Instead, if this is possible, we would prefer one large 'demonstration' sundial - ideally in wood or plastic (not metal, as that would be expensive, plus too heavy for a teacher to hold). Though Mr Honey offered to have something specially designed/manufactured for volume sales to schools, it is likely to take some time to implement. Hence my plea to this Mailing List - asking if there are any 'commercial Teaching Sundials' already on the market, and if so, can anyone point me towards the supplier of them. We have a budget of 500 Pounds, for this. Sincerely, Martina Addiscott. --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Book of Time Sundial....
Hello Roderick all, The Dutch Sundial Society had its quarterly meeting last Saturday in Utrecht. A new member, Karin ten Kleij, pointed out some Sicily dials she had found in the internet, which are adorned with the 13 constellations. An intriguing coincidence! In these cases the constellations are not used for the date lines, as is the case with the Genk dial, but for decoration, apparently from a modern astronomical point of view. My Italian is weak, so don't blame me for not giving a summary of the stories. The links are: http://web.tiscalinet.it/astrofilicatanesi/meridct8.html http://astrocultura.uai.it/strumenti/meridiana/meridianarivoluzionaria.htm Best regards, Frans Maes On 20-3-2011 9:22, R Wall wrote: HI all, I found this lovely “Book of Time sundial”: http://www.fransmaes.nl/genk/en/gk-x12-e.htm I’ve also found a stone book accessory from a monumental supplier here in Australia. This looks as if it should be suitable for a book sundial. But as the sundial will be out in the weather, and I want the sundial to last. What stone should the book be made from? Also any ideas on how the inscription should be done for it to last? Regards, Roderick Wall. --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Moscow sundial?
Dear all, Willy is right in noting that instructions on information panels don't work. I very much like the footprints. I think they are effective, with or without explanatory text. From left to right in the attached composite picture (in black white; the color version, at 39 kB, did not pass the medieval-sized size filter): Riverwalk, Augusta (Georgia); Hasselt (Belgium), designed by Willy Leenders (2000); Culemborg (Netherlands), my design (2009). Best regards, Frans On 11-3-2011 16:24, John Carmichael wrote: Some human analemmatics have footprints indicating where people should stand. attachment: feet-bw.jpg--- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Calendar 2011 - The Best Sundials of Poland
Dear Darek, Thank you for this beautiful Christmas present! I'll hope to keep it longer than just one year. Best regards, Frans Maes On 8-12-2010 1:59, Darek Oczki wrote: Dear friends As the year 2011 is approaching I would like to present to all of you a special calendar showing the best of Polish sundials. I hope you gonna like it as much as the works of Polish masters of gnomonics. You may download the calendar from here: http://www.gnomonika.pl/files/calendar_2011.pdf (Note: the hi-res file is over 25MB) --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: BSS bulletin copy of article
Dear Willy, I will send you a copy. Kind regards, Frans Maes On 30-11-2010 18:14, willy.leend...@telenet.be wrote: Preparing an article for the bulletin of 'Zonnewijzerkring Vlaanderen' (The Flemmish Sundial Society) I am in search of a copy of Sarah Syman, Shadow Clocks and Sloping Sundials of the Egyptian New Kingdomand Late Period: Usage, Development and Structure, The British Sundial Society Bulletin 98.3 (1998), 30-36 Who sent me that copy? Willy Leenders Hasselt in Flanders (Belgium) --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: A short stay in Italy
Dear Tony, The ITINERARIO ARTE SCIENZA: http://www.astrofilibresciani.it/Attivita/Attivita_Scuole/Tour_Astronomico.htm has several stops related to astronomy and sundials. Last year I downloaded an English version, but it seems that presently only the Italian version is available. I think you can handle that. You would especially want to save the city plan going with it. Have a nice trip! Frans Maes On 13-10-2010 17:40, Tony Moss wrote: Fellow Shadow Watchers, I shall be staying near Brescia in Lombardia for three days in mid-November but with a hire car and a few spare hours to fill outside my visit to the Perazzi factory. Any suggestions for dials worth seeing in the area or local museums would be most welcome. Tony Moss --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Digital Gnomonic Books project
Dear Nicola all, Thank you, Nicola, for collecting all these links to old sundial texts. Most of the classical textbooks of gnomonics can be found here. I had some good hours browsing through this impressive collection. I couldn read only some, but often enjoyed the nicely engraved figures. Unfortunately, some of the books have separate large figure pages, folded into the book, and the library staff usually did not care to unfold these before scanning. Best regards, Frans Maes nicolasever...@libero.it wrote: Dear Friends, good year to all! In this days a new great gnomonic project is starting on my web site http://www.nicolaseverino.it I linked around 300 of most important books about the gnomonica, digitized from several important Digital Library in the world. The collaboration is welcome to point out new links of digitized books of gnomonica to add at this list. Please visit my web site for see this news and write me for each informations and collaboration form. Thanks and enjoy the new project! Best wishes, Nicola Severino --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Translations
Dear Steve and all, Three free translators I sometimes use for websites or short texts, are: - Babelfish: http://babelfish.yahoo.com/ - Google: http://translate.google.com/ - Prompt: http://www.online-translator.com/ You may try each on the AFP press release: http://www.google.com/hostednews/afp/article/ALeqM5gFPjvks3c5EemskZkRWhCB-Fu_IA and judge the quality (when you read French and English) or see whether you get the message. In this case, the photos set the stage for the story, so that makes it easier. For this limited sample, I think Prompt does a slightly better job than Google, and Babelfish is last. What do you think, Joël? Prompt marks the words that were not translated, such as proper names, which is handy. More generally, a simple original, both in terminology and in grammar, leads to a better translation. That's why e-mail messages often translate badly. For me, the most important paragraph in this text is how the sundial should function: Innovation de ce cadran: c'est l'ombre même du parapet projetée sur la voûte du barrage qui permet de lire l'heure solaire. Chaque heure est matérialisée par une ligne horaire confectionnée avec des plaques en lave émaillée: ocres pour les heures du matin, vertes pour celles de l'après-midi. L'heure solaire est connue lorsque l'ombre tangente l'une de ces lignes. which translates into: Babelfish: Innovation of this dial: it is the shade even parapet projected on the vault of the stopping which makes it possible to read the solar hour. Each hour is materialized by a “time line” made with plates in enamelled lava: ochres for the hours of the morning, green for those of the afternoon. The solar hour is known when the tangent shade one of these lines. Google: Innovation of the dial: the very shadow of the parapet onto the arch dam, which allows you to get the solar time. Each hour is marked by a line timetable made with plates in enamelled lava: ochers for the morning, green for those in the afternoon. The solar time is known when the shadow tangent one of these lines. Prompt: Innovation of this face: it is the shadow of the breastwork cast on the arch of the dam which allows to read the solar hour. Every hour is fulfilled by a line per hour made with plates in interspersed lava: ochres for hours, green for those of afternoon. The solar hour is known when tangent shadow one of these lines. In the original, the most essential word of the entire story is tangente, which apparently is used as a verb: the shadow of the edge touches (kisses, osculates) an hour line. This may be an uncommon usage, as all three utilities interpret it as an adjective and try to make at least some sense out of it. And I wonder what the lava strips are made of... Best regards, Frans Maes Steve wrote: Confrere: I am interested in translating email and web pages into English. I use as example the note from Joel about the Castillon Dam. The link contained in his email is to a web page in French and so my question. I use Eudora for mail and have receded to FireFox version 2.00.18. However, I have tried various translators with several versions without much success. My question. Does anyone use a translation program for email and the web, with success. Thanks Steve Yorktown VA At 01:13 PM 6/15/2009, robic.joel wrote: Hello Frans and all, It's the Castillon Dam, see this AFP article, you will understand easiler the principle http://www.google.com/hostednews/afp/article/ALeqM5gFPjvks3c5EemskZkRWhCB-Fu_IA More information is available in French Cadran Info magazine (including modelling by Gérard Baillet and calculations from Denis Savoie). Best regards Joël 48°01'25'' N, 1°45'40 O --- http://www.cadrans-solaires.fr/ - Original Message - From: Frans W. Maes f.w.m...@rug.nl To: Josef Pastor j.pas...@gmx.de Cc: 'Sonnenuhr (Uni Köln)' sundial@uni-koeln.de Sent: Monday, June 15, 2009 4:56 PM Subject: Re: French dam to be world´s biggest sundial Dear all, The audio track of the video is bad, so I was unable to hear which dam this is, and how the sundial would function. Does anyone know more about this intriguing project? Best regards, Frans Maes Josef Pastor wrote: Dear Dialists, Famous French Denis Savoie presents a French dam to be world´s biggest sundial on You Tube. http://www.youtube.com/watch?v=7-NJIhliZG4 Best regards Josef Pastor ** --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial E-mail message checked by Internet Security (6.0.0.386) Database version: 5.12160 http://www.pctools.com/en/internet
Re: Wall declination using google earth
Dear Roger, Damia and all, Instead of fiddling with the display settings of the monitor, I use the Pen Tool of my image processing program, Paint Shop Pro, to measure wall declination. I guess other programs have a similar tool. When drawing a straight line over a sharp picture element parallel to the wall (roof ridge, roof edge, street side,...), the status bar shows the direction in 1 decimal. I assume that it is the arc-tangent of the x and y displacements in pixels. With a good quality of the satellite image, the accuracy is about 0.5°. An assumption for this method is, of course, that the x and y pixel distances of the satellite image are equal. Best regards, Frans Maes Roger Bailey wrote: I routinely use Google Earth to determine wall declination. Depending on the quality of the picture, resolution to within one degree can be achieved. The default orientation for Google Earth is straight north up for the center of the starting image. I have a flat screen with vertical sides and horizontal top and bottom that are useful reference lines. Check your screen settings. On most displays these days, x and y are not equal. I had to choose a display settings to match the dimensions of the monitor. There are examples of wall declination using Google Earth in some of the presentations on my website. Timelines #5 may be the most useful. Regards, Roger Bailey Walking Shadow Designs www.walkingshadow.info -- From: Damia Soler Estrela l...@damia.net Sent: Monday, June 08, 2009 5:53 AM To: Sundial List sundial@uni-koeln.de Subject: Wall declination using google earth Hello: You are talking about physical declinometers in order to know the wall declinations, I think that is the most acurrate method, but I have been using google earth, you can see the wall of the buildind or the aligned street, and could calculate the declination from North? (You have a rule to measure the x and y axis, or read the coordinates). What do you think about the accuracy of this method? Do you have any information about the accuraccy of google earth in order to measure declination? Best regards Damià --- https://lists.uni-koeln.de/mailman/listinfo/sundial No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.339 / Virus Database: 270.12.55/2160 - Release Date: 06/07/09 05:53:00 --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: French dam to be world´s biggest sundia l
Dear all, The audio track of the video is bad, so I was unable to hear which dam this is, and how the sundial would function. Does anyone know more about this intriguing project? Best regards, Frans Maes Josef Pastor wrote: Dear Dialists, Famous French Denis Savoie presents a French dam to be world´s biggest sundial on You Tube. http://www.youtube.com/watch?v=7-NJIhliZG4 Best regards Josef Pastor ** --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Duixons sundial
Hi Chiu, John all, The sundial by Duixans (1984) reminds me of the well-known photo of a gentleman checking his watch against a spiral sundial in a rainy scene. Hopefully the attachment (26 kB) makes it to the List. The photo is from Heinz Schumacher, Sonnenuhren. According to the caption, it was designed by J. Masuet and installed in Alpicat (prov. Lérida), Spain, in 1974. Best regards, Frans Maes inline: Masuet2.jpg--- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Duixons sundial
Hi Alexei all, Interesting, yes. If only because the dial doesn't work properly. At least, not always. Around the equinox, a sharp-edged shadow is cast on both sides of the strip, perpendicular to the strip's axis, and the hour marks are correct. Towards the solstices, the shadow boundary on one side gets oblique and fuzzy, whereas the edge on the other side shifts away from the correct position. The deviation is some 25 minutes at most. John Moir observed this in a model, made from a wide elastic strip, and reported the results in the Bulletin of the British Sundial Society, nr. 95.1. See also www.fransmaes.nl/sundials, click Sundials?? in the menu. Best regards, Frans Maes Alexei Pace wrote: Do not forget the very interesting sundial by Piet Hein as well which is based on the helix. On Thu, May 14, 2009 at 8:26 PM, Frans W. Maes f.w.m...@rug.nl wrote: Hi Chiu, John all, The sundial by Duixans (1984) reminds me of the well-known photo of a gentleman checking his watch against a spiral sundial in a rainy scene. Hopefully the attachment (26 kB) makes it to the List. The photo is from Heinz Schumacher, Sonnenuhren. According to the caption, it was designed by J. Masuet and installed in Alpicat (prov. Lérida), Spain, in 1974. Best regards, Frans Maes --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Interesting sundial in Japan
Sorry for the late posting, but we were off-line for a week. I agree with Gianni: this seems to be a correct and interesting design. Just a guess: the dots may be led's that show the time also at night. And as Tokushima is less than 0.5° west of the Japanese time zone meridian, this might be civil time (except EoT correction). Best regards, Frans Maes Gianni Ferrari wrote: As others have already written it is a vertical sundial, facing South, with polar style, with its center in the point A of the attached figure. Since the style continues beyond the disk, the part BC of it can work as a polar style of a sundial facing North, with center in B, drawn on the hidden face of the disk. Even if the style BC is very short, being the northern face illuminated only in the extreme hours of the day, the shadows would be long enough to reach the edge of the disk. The northern side of the disk has been being illuminated from 5:30 to 8:00 (around) and from 16:00 to 18:30 The lines of the hours on the northern face would be those drawn on the southern face for the same hours (see the Roger Bailey’s drawing) Does someone know if the hours are written also on the northern face of this sundial? Best Regards Gianni Ferrari --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Experimental Method for Earth Radius
Dear John and all, Quite an interesting idea! I wondered how the terminator on a sea-side building looks like. In particular, is it sharp enough to enable the proposed observations? Is there perhaps a YouTube movie showing the terminator? And would atmospheric refraction come into play somehow? Best regards, Frans Maes JOHN DAVIS wrote: Dear Dialling Colleagues, I'm forwarding this message from another mailing list as I believe it may be of interest to all sun-watchers. Mathematicians amongst you might like to work out the details of the 'fudge factor'. Regards, John --- Dr J Davis Flowton Dials --- On *Sun, 1/3/09, Brian Whatcott /betw...@sbcglobal.net/* wrote: From: Brian Whatcott betw...@sbcglobal.net Subject: [rete] Experimental Method for Earth Radius To: sexta...@yahoogroups.com, r...@maillist.ox.ac.uk Date: Sunday, 1 March, 2009, 4:38 AM I am relaying this note from a physics teachers list, believing it may be of interest to you. For me, it carried the same kind of frisson as reading about Harrison's stellar transit method for timing chronometers. Brian W David Bowman wrote: I've come up with a fairly simple means of measuring/calculating the size of the earth using only local measurements (not requiring multiple sightings at far away locations like Eratothenes' method needs). The idea is to observe and time the motion of the terminator at sunset/sunrise ascending or descending the face of a building, pole, or other tall structure with an exposed vertical face. It is a fairly simple exercize in trigonometry to realize that if one is situated on the equator during an equinox that the terminator ascends vertically at sunset and descends vertically at sunrise with a constant acceleration that is related to the rotation rate of the earth and the radius of the earth. In this situation it is a high school-level calculation to see that if a is the vertical acceleration of the terminator then the radius R of the earth is R = a*(T/(2*[pi]))^2 where T is the duration of one solar day. If the observing location is not on the equator then there is a correction for the local latitude of the observer. And if the time of observation is not during an equinox then there is another correction involving the declination of the sun due to the tilted path of the sunrise/sunset at the horizon. Figuring out these corrections is *not* at the high school level, but they don't involve anything more than a lot of complicated trigonometry. The date/place corrected formula involving these corrections is R*F = a*(T/(2*[pi]))^2 where F is a fudge factor that depends on the complications. According to my calculations, the explicit value of F is F = cos^2(D) + sin^2(L)*(cos^2(D) - tan^2(D)) where D is the declination of the sun on the date of observation and L is the local latitude of the observation. The actual value of a, being only a few cm/s^2, is plenty slow enough for easy observation of motion of the terminator up or down the observing wall using a wristwatch. To get the acceleration only a few timings are needed between some fiducial marks on the wall whose separation distance is measured. BTW, in order for the method to work properly the horizon needs to be an unobstructed 'true' horizon that accurately represents the effectively smoothed surface of the earth. This means that the observation ought to be done along a seacoast or the coast of a great lake that can't be seen across from the top of the observing wall. For those whose budgets are unlimited this means that a field trip to Miami Beach for the purpose of observing the sunrise on the beachfront hotels would make a very nice educational experience. David Bowman ___ Forum for Physics Educators phy...@carnot.physics.buffalo.edu https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l Do not reply to this message UNLESS you want to reply to the whole list. - To unsubscribe, e-mail: rete-unsubscr...@maillist.ox.ac.uk For additional commands, e-mail: rete-h...@maillist.ox.ac.uk --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Greetings
Dear Leandro, Perhaps you found out already that the sundial in front of the Adler Planetarium was designed by the great sculptor Henry Moore. He was a master of simplicity! It certainly is large: 3.6 meter in diameter. That's why it has such a heavy foot. You can find more about this dial in my website www.fransmaes.nl/sundials. Choose 'equatorial' and scroll down to the last thumbnail in the section 'Armillary spheres - Europe'. Much success, and keep us informed about your ambitious project! Frans Maes Leandro V. Rabelo wrote: Hello people, I read your comments here every day and this is my first time I’m writing to you. Almost one year ago I saw in the internet a monument at Adler planetarium in Chicago, when I discovered that the monument was a sundial, and then, what a sundial was, I started studying about it to try to do one here in my city, I know that this is an ambitious project but I’m studying for that and I hope this can become a reality. I’m planning to make a three meters diameter equatorial sundial to put in an important place here, I know that I have many things to learn to make an accurate sundial, but I just want to say that I learned many things here reading your e-mails and now I’ll study more and more to make my own sundial, please don’t hesitate if you have any suggestions and when I have news about my sundial I’ll post here. Best regards, Leandro Rabelo Maceió, Brazil. (9°39'53.64S - 35°41'47.56W) Veja mapas e encontre as melhores rotas para fugir do trânsito com o Live Search Maps! Experimente já! http://www.livemaps.com.br/index.aspx?tr=true --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Vertical South dial with horizontal gnomon
Keith, What you want is quite simple, once you grab the idea. Imagine a classical vertical dial, including its pole-style. Take one point somewhere on this style, and remove the style except this point. How to prevent it from falling down? Yes, put it on top of a supporting rod. In your case, use a horizontal rod, perpendicular to the dial face. This approach can be used on any dial, whatever its orientation. For a vertical decliner, see the example by John Carmichael: http://www.advanceassociates.com/WallDial/. Do read also about his shadow experiments (the bottom two links in that page). Much success, and share the result! Frans Maes www.fransmaes.nl/sundials Keith E. Brandt, WD9GET wrote: Sunny friends, For various reasons, I'm wanting to build a rather different dial. The plan is for a south-facing vertical dial, but I want to design it with a horizontal gnomon. Waugh states that a vertical south-facing dial has the same hour lines as a horizontal dial at the colatitude. Therefore, to calculate the positions of the hour lines, I used the following formula in Excel: =90-(180/PI())*ATAN((TAN(L8*PI()/180)*SIN(Colatitude*PI()/180))) With L8 being the angle of the sun from noon, calculated by [number of minutes from noon] * (15/60). What needs to be changed to make this work properly with a horizontal gnomon? Keith --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Unknown solar device?
Hi Patrick, This device obviously is a Wheatstone folding-type polarization sundial. See Allan Mills' article The sellotape sundial in BSS Bulletin 98.1, p. 3-9, especially figure 7. Best regards, FRans Maes Patrick Powers wrote: Can anyone throw light on the interesting device to be found at http://tinyurl.com/5gnqz6 It appears to be a genuine scientific instrument made by Smith Beck 6 Coleman St. London I am told that this company changed its name to Smith in about 1850. Size = 145mm X 120 It folds in two places it has a smoked glass panel 85mm X 65mm and a glass 'protractor' like panel with the numbers 12,1,2,3,4,5,6,7,8,9,11,12,1,2,3,4,5,6,7,8,9,11,12 written so that it reads correctly when read in the smoked glass. There are small clear panels pointing to each alternate number from a circle in the centre. Many thanks Patrick --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Seismic Shift at Braunschweig
Dear Roger, I forgot earlier to comment on one line of yours. The later Braunschweig sundial, 1346 perhaps, represents a seismic shift in the understanding time and the universe. The angles on this dial are correct for a polar gnomon and would show equal time throughout the seasons. This is a fundamental shift in how people perceived time. This dial may be the first sundial crafted on the basis of this new understanding. It may represent a significant step in European knowledge of the universe. If the dial actually had a polar gnomon and the dates based on the construction of the church are correct, this dial came before the Ibn Al Shatir dial in Damascus dated to 1371, often noted as the first polar, planar sundial. Is there a specific source for the last statement? The Islamic sundial of 1371 is a very sophisticated instrument. Therefore I like to think of it as a culmination of Islamic astronomical science, a product of perhaps centuries of scientific development, rather than as a novelty. Best regards, Frans Maes --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: equal and unequal hours
Dear all, [EMAIL PROTECTED] wrote: It is true that the first mechanical clocks was on the towers around the begin of the 1300. And the first vertical sundials with the polar gnomon was done arond the first half of 1300. The interesting articles of Curt Roslund in the BSS Bulletin, september 2005, pag. 116-119, show the vertical sundial of Braunschweig Cathedral of 1346 with the equal hour lines and a polar gnomon. The 1346 dial now has a polar gnomon. As recent as 1964 there was no gnomon, merely a large hole (Zinner). It is not known, how the original gnomon was oriented. In my view, it is unlikely that it was a pole-style. The angles were laid out according to the 'Erfurt formula', as Zinner and Roslund point out. This rule does not say anything about the orientation of the gnomon. If it was intended to be pointing at the celestial pole, the formula would most probably have provided accurate instructions for that. To answer Roger's question: The dates of the 1334 and 1346 dials were deduced from the building history of the cathedral, assuming that they were laid out at the time of completion of the particular buttresses. Regards, Frans Maes --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: equal and unequal hours
Dear all, The DGC catalog mentions 4 sundials on the Braunschweig cathedral. The discussion does not refer to the 'new' ones from 1518 and 1715, but to two older ones, from about 1334 and about 1346. The hour line patterns (attached) show two ways of playing around with the lines, in the trial-and-error process that took place according to Zinner. Roger, I will send you a pdf with the last three pages of Karlheinz' BSS article (2.7 MB). I think they comprise the relevant part for this discussion. Roger Bailey wrote: Google quickly finds pictures and information on the Braunschweig Cathedral sundial. http://commons.wikimedia.org/wiki/Image:Braunschweig,_Dom_St._Blasii_mit_Sonnenuhr.jpg The pictures show a dial with the words Anno 1716 across the top. A text reference identifies Hans Geog Hartel with the sundial is 1659. http://historydb.adlerplanetarium.org/signatures/edit.pl?edit_id=6954 Is there an earlier sundial dating back to 1346 with the same characteristics, polar gnomon and equal hours? Can any of you scan Carl Roslund's BSS article and email me a copy? Regards, Roger inline: Braunschweig1-2b.gif--- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: equal and unequal hours
Dear Frank (King), Frank King wrote: No doubt the transition to equal hours (whether starting at noon, midnight, sunrise or sunset) was gradual but I feel it long predates mechanical clocks. Do you have any evidence supporting your feeling? I have studied the question when the pole-style sundial, reading equal hours, appeared in the Western world. Zinner appeared to be the most important reviewer of the few written primary sources. My conclusion was that the pole-style dial appeared around 1400, hence a century or so AFTER the introduction of mechanical clocks. I have written an article about this (in Dutch ;-) for the Dutch and Flemish bulletins in 2004. It has been suggested that the pole-style dial (and hence equal hours) was brought to the West by returning crusaders. Karlheinz Schaldach gave convincing arguments against this in BSS Bulletin 96.3. Best regards, Frans Maes --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: equal and unequal hours
Dear Frank, Frank King wrote: You don't need a polar-oriented gnomon to indicate equal hours (starting at noon or midnight) although it certainly helps. The way I view the transition from temporary to equal hours follows Zinner's reasoning. The usual medieval sundial was vertical and semi-circular, with 12 (equally spaced) temporal hour lines. A perpendicular gnomon was inserted into the center, where all lines intersect. How to adapt this lay-out to the equal hours of clocks? Zinner imagines that people have been experimenting with bending the gnomon and/or slightly rotating the hour lines to or away from the meridian, until success. One could have attained the same result by moving the gnomon down (until its tip would fall on the imaginary pole-style arising from the center), but that would have required a more difficult mental step. Of course this reasoning applies only to 'anchored' equal hours, which start from a fixed time point in the day, such as noon or midnight. I would not dare to speculate on how sundials for Italian (or Babylonian) hours evolved. When did such dials emerge? Do you know, Gianni? Best regards, Frans Maes --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Advice wanted, on 'Analemmatic' sundial orientation
Dear John, Do you think Mr. Phillips really is willing to go along with such an idea? If so, I have been considering the options a bit further. The explanation in Karl Schwarzinger's webpage has January outermost and December innermost. For a human shadowcaster, it would be easier to have June innermost, as his/her shadow will be short. Next May + July, which see about the same solar declination, then April + August, etc. The spacing of the month rings can be adapted to the average person's shadow length in that month. You might stop at March + September, as there is not much going on in the remaining months, according to the Year Calender in the Estate's website (http://www.kentwell.co.uk/). The type of pavement/planting may limit the accuracy of reading. If one does not care about high precision, one could average the azimuth values of two months (like May and July) and use this single value. The placement of the month names is free. They could be aligned with the main driveway, thereby fulfilling another of Mr. Phillips' requirements. We still have the wish/requirement for scales having the hour points at the south side. This could be met by reversing the lay-out, as follows: Rotate the rings by 180 degrees. The person walks the ring for the present month until his/her shadow points at the center spot/post. Then he/she reads the time from his/her position. This makes the dial even more 'interactive' than the usual analemmatic dial! What do you think? Best regards, Frans Maes [EMAIL PROTECTED] wrote: YES!!! Why didn't any of us think of this? John --- On Sat, 28/6/08, Frans W. Maes [EMAIL PROTECTED] wrote: From: Frans W. Maes [EMAIL PROTECTED] Subject: Re: Advice wanted, on 'Analemmatic' sundial orientation To: [EMAIL PROTECTED] Cc: sundial@uni-koeln.de Date: Saturday, 28 June, 2008, 9:51 PM Dear John, What you describe resembles an azimuth sundial. See for instance the Plochingen sundial in Karl Schwarzinger's collection: http://members.aon.at/sundials/bild44_e.htm In this case, there would be no clear-cut alignment with anything, including the (in)famous path... Best regards, Frans www.fransmaes.nl/sundials --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Advice wanted, on 'Analemmatic' sundial orientation
Dear John, What you describe resembles an azimuth sundial. See for instance the Plochingen sundial in Karl Schwarzinger's collection: http://members.aon.at/sundials/bild44_e.htm In this case, there would be no clear-cut alignment with anything, including the (in)famous path... Best regards, Frans www.fransmaes.nl/sundials [EMAIL PROTECTED] wrote: Forgive me, for returning with yet another tiresome proposal: On reflection I suspect Mr Phillips may not be totally wrong-headed. On any one day the azimuth of the shadow of a static human shadow-caster can be marked by a circular arc of hour-marks or indeed by hour-marks fixed along two straight lines parallel to Mr Phillips' driveway. This arrangement would be accurate on only two days each year. But it would be a simple matter to move all the hour-marks (except the noon-marker) say once a week, or less frequently at the solstices when Kentwell Hall might be busiest. Anyone on this mailing list could print off the necessary page of solar azimuths, or preferably shadow azimuths, at weekly intervals. So I would envisage a single spot, perhaps in the middle of a decorative compass rose, for the shadow caster to stand on. The human gnomon might be at the centre of a circle of, say, 360 identical bricks, at 1-degree intervals. The print-out would tell Mr Phillips which brick should hold each hour-mark for the current week; it could painlessly incorporate the equation of time and daylight saving. No self-respecting diallist could be happy with this proposal, but it does seem to meet most of Mr Phillips' criteria for a human sundial, albeit no longer analemmatic. John Lynes -Original Message-From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Dear Sundial Experts, I have recently joined this Mailing List, and hope that any members will be able to give me some assistance on the following situation. Our local Stately Home (Kentwell Hall, Long Melford, Suffolk) is considering installing an Analemmatic sundial, as a new interactive attraction for visitors - but we are getting 'conflicting' advice, on whether this 'Human Sundial' will work in the way we want it to. We have been in discussion with Modern Sunclocks (apparently the acknowledged 'experts' for these features), who have told us that its central scale of dates must be aligned North/South - plus that hour markers must be correctly positioned on an elliptical ring, and which would lie on the Northern side of that scale of dates. Photographs on their website ( www.sunclocks.com ) confirm this. However, our 'Director of Operations' (Mr Phillips) absolutelyINSISTS that he wants the scale to run exactly parallel with ourmain driveway - on a compass bearing which is about 162 degreesfrom North, with the hour points placed on its Southern side.He also wants the hour points to form an exact semi-circle, andnot be elliptical in shape. Mr Phillips refuses to accept thathe cannot arbitrarily position the Human Sundial feature as hewishes, and says that it must be possible to create this so thatit could then align with the existing layout of buildings/paths. Can anyone on this Mailing List tell me whether it is possible toinstall a Human Sundial to fit any existing orientations, (withappropriate re-calculation of its component parts) - or, if not,just confirm that it must be as Modern Sunclocks have told me. I can then show the 'weight of evidence' to Mr Phillips. BecauseKentwell Hall is a well-known Stately Home (open to the public),we should not want to become a 'laughing stock' by installing afeature which does not work - despite Mr Phillips assurance thatall types of sundial can be adjusted to work, in any location. Looking forward to all comments (to this List, or sent privately). Sincerely, Alison Shields. --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Rhine Sundials
Hi John and other travelers/vacationers, In case you have some time in Amsterdam before embarking for this Grand Tour, enjoy the Amsterdam Sundial Trail: www.fransmaes.nl/sundials/amsterdam . In Strasbourg you should not miss the sundials at the south transept of the Cathedral and the 26-sided dial in the Botanical Garden. I'll e-mail you some pictures. Have a wonderful trip! Frans John Carmichael wrote: Like many of us, I plan on doing a little sightseeing in Europe this summer and would like to see some good sundials along the way. I’ll be traveling by boat up the Rhine river from Amsterdam to Switzerland from July 4 to July 13. We’ll be stopping at these locations: Cologne, Koblenz, Rudesheim, Mannheim, Heidelberg, Strasbourg, Basel, Gruyeres, Montreux, Zermatt, Andermatt, Lucerne, and Zurich. I’d be most grateful if anyone could tell me about any “must see” sundials in any of these places. Any website links or sundial trails of the Rhine valley would be helpful. Thanks in advance, John John L. Carmichael Sundial Sculptures 925 E. Foothills Dr. Tucson AZ 85718-4716 USA Tel: 520-6961709 Email: [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] *Websites: * (business) *Sundial Sculptures:* http://www.sundialsculptures.com http://www.sundialsculptures.com/ (educational) *Chinook Trail Sundial: *http://advanceassociates.com/Sundials/COSprings/ (educational) *Earth Sky Equatorial Sundial:* http://advanceassociates.com/Sundials/Earth-Sky_Dial/ (educational) *My Painted Wall Sundial:* http://www.advanceassociates.com/WallDial (educational) *Painted Wall Sundials:* http://advanceassociates.com/WallDial/PWS_Home.html (educational) *Stained Glass Sundials:* http://www.stainedglasssundials.com http://www.stainedglasssundials.com/ (educational) *Sundial Cupolas, Towers Turrets:* http://StainedGlassSundials.com/CupolaSundial/index.html http://stainedglasssundials.com/CupolaSundial/index.html --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Eclipses
Hi Hans, One such sundial is at the Tourist Office in Virton (Belgium). It was made for the eclipse of 11 August 1999. Virton is in the very south of Belgium, and only this tiny region saw a totality. For a photo: - go to http://www.gnomonica.be/ - click Sundials in Belgium - click Wallonia (the French speaking part) - under per Province, click Luxembourg - click Virton - click the right-hand thumbnail The indicated date line is marked Eclipse du 11 Aout, and the dot shows the time of occurrence. Best regards, Frans Maes www.fransmaes.nl/sundials Hans Clugston wrote: My work has kept me away from sundials for a time, but now, in a way, has brought me back. I represent TravelQuest International, the world leader in eclipse chasing tours, and got to wondering if there is a list of dials commemorating eclipses. I did not find much from internet searching. I apologize in advance if I missed something before posting this. If anyone can provide a pointer or two, I would appreciate it. Hans Clugston Arizona --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: A Most Beautiful Dial!
Dear John, Thank you for bringing this to our attention! The Wilanow Palace sundial photo and its description can also be found at: http://en.wikipedia.org/wiki/Image:Warsaw_Wilanow_Palace_sundial.jpg This is indeed an interesting sundial, but also an interesting photo. Karl Schwarzingers photo led him to state that Chronos holds style with a pierced gnomon shaped as sun, and indeed it looks that way in his photo. The hi-res one clearly shows that the supposed pierced gnomon actually is a sun face stuck to the wall. So the date is read at the tip of the rod, which fits in with the date the photo was taken: June 25. In addition, the rod is not a pole style, which is clear from the fact that its shadow does not line up with the hour lines. Best regards, Frans John Carmichael wrote: Recently I came across a website that has a high definition photo of what I think is one of the world’s most beautiful sundials. It is a sundial made of sculpted painted plaster or stone (I can’t tell which), and it’s located on a wall of The Royal Palace of Wilanow in Warsaw Poland. (Actually, it’s a multiple dial with three separate faces). I have known about this dial for years now from Karl Schwartzinger’s website. But Karl’s photo was not of high quality and I never was able to find a high resolution photo of it until now. If you have a slow modem, It’s worth the wait to see it in high definition. High Definition Photo (2 MBs) : http://upload.wikimedia.org/wikipedia/commons/b/b1/Warsaw_Wilanow_Palace_sundial.jpg You must also see the closeup photos of it at this website (click on the word “dalej” under the photo): http://www.wilanow-palac.art.pl/index.php?id=195 Here are the other photos of it on Karl’s site: http://members.aon.at/sundials/bild33_e.htm Enjoy! John Carmichael* * *Dial 31* *Delineator: *John Hevelius, astronomer of Gdansk and Adam Adamandy Kochanski, royal librarian and mathematicians *Painter: *unknown *Location: *Poland, Warsaw, The Royal Palace of Wilanow *Date: *1681-1682, Restored 1995 *Photo Origin: *Photo ‘a’ was taken by Arnold Paul on 06-25-2006 and is copied from Wikimedia.org website below. Photo ‘b’ is by Karl Schwarzinger and was sent to us by him. *Photo Permission: *Photo ‘a’ is used following terms of the license below. Photo ‘b’ is used with permission from Karl Schwarzinger. Please do not copy photo ‘a’ without using the license available online. Please do not copy photo ‘b’ without permission from Karl Schwarzinger. *Karl Schwartzinger’s Website: *http://members.aon.at/sundials/bild33_e.htm *Website: *http://www.wilanow-palac.art.pl/index.php?id=195 *Website: *http://commons.wikimedia.org/wiki/Image:Warsaw_Wilanow_Palace_sundial.jpg *Creative Commons License: *http://creativecommons.org/licenses/by-sa/2.5/ http://advanceassociates.com/WallDial/Pinkies/PWS_031a.jpg http://advanceassociates.com/WallDial/Dials/PWS_031a.jpghttp://advanceassociates.com/WallDial/Pinkies/PWS_031b.jpg http://advanceassociates.com/WallDial/Dials/PWS_031b.jpg --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Sundial animation?
Hi all, Looking for something else, I happened to hit upon this link: http://www.anistock.com/3d-animation-of-a-monument-rotating-cpi8466.html, showing an 'animation' of a multiple sundial. An odd sundial: note the missing and incorrect gnomons. Strangely enough, it bears a strong resemblance to a sundial in the park of the Menkema Mansion in Uithuizen, The Netherlands. That one has the same erroneous gnomon, but no missing gnomons. And it has an angel's face below the star. See the attached thumbnail. More pictures can be found in my website www.fransmaes.nl/sundials/. Any comments? Best regards, Frans Maes inline: menkema.jpg--- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Perspective
Hi all, Roger is right. The width/height ratio of the computer display can simply be changed by the manual controls below the screen. When sending pictures, or placing pictures on a website, one cannot be sure that the addressee or visitor sees what one intended him/her to see. However, the dimensions should be correct when measured in pixels. Now back to perspective correction. Let's say I take a (digital) photo of a vertical dial up a wall. The location forces me to take an oblique shot. Let's also say I am sure that the dial (or its frame or setting) is rectangular, with horizontal and vertical edges. Now I would like to reconstruct the view, as if I took the photo straight in front of the center of the dial. That way I would be able to measure the substyle angle, check the correctness of the hour lines, etc. Is there a procedure that enables me to make such an exact reconstruction? My graphic program Paint Shop Pro X has a 'perspective correction tool'. I tested it as follows: I drew (in PSP) and printed a square of 150 mm sides and a rectangle of 100 mm wide and 200 mm high. Then I took oblique photos. The perspective correction tool produced rectangles which were always too wide. The error varied between 2 and 7%, depending on the amount of cropping applied beforehand. If anyone would like to give it a try, the oblique photos in their original size (1944 x 2592 pixels) can be found here. Only the contrast has been enhanced. square 150 mm (16 kB): www.fransmaes.nl/sundials/perspective/square-150.gif rectangle 100 x 200 mm (19 kB): www.fransmaes.nl/sundials/perspective/rect-100x200.gif Best regards, Frans Maes Roger Bailey wrote: What we see is determined by where we stand. This is a reality in so many aspects of life. This applies to sundials. We were all misled a while back by the distortions from perspective on an excellent sundial design. This was a useful experience. I have recently be trying to correct for perspective to analyze a historical sundial and and wish to share this useful experience with you. The normal photo editing tools can correct for mild distortion from perspective but generally fail to mathematically resolve the distortion. We rarely know the input parameters, where we stood and how we set the camera. Some lines can be made parallel and perspectives skewed but are these true? Usually not. Faced with this problem, I acquired new pictures of the sundial from known points of view with minimum perspective correction. In the end this worked but in the meantime I discovered that my view of the world through my computer was distorted. I set the display at 1024 x 768 as this gave me reasonably sized print and icons. When analyzing these sundial pictures I found that they did not display correctly. Measuring my monitor I determined that the height to width was 80%. But 768 x 1024 is 75%. Everything I saw on my screen was distorted by perspective. An alternative computer system gave me 65%. Changing to 1024 x 1280 gave me 80% and I could then go on with my analysis but it caused me to think Is what I am seeing reality. I was fooled in this simple case. What about the rest of what we perceive about our world? We can be fooled by perspective. Choose where you stand carefully and be aware of your perspective. There are many distortions to reality. Again everything I need to know about life I learned from sundials. Regards, Roger Bailey --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Amsterdam Sundial Trail
Hi all, Those of you who consider visiting Amsterdam in the near future might have a look at the Amsterdam Sundial Trail website: http://www.fransmaes.nl/sundials/amsterdam/ It presents some interesting dials and dials in interesting locations, such as canal house gardens. A trail description with detailed directions can be downloaded and printed to take with you as a travel guide. Best regards, Frans Maes --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Sundials in Hong Kong?
Hi Doug, A beautiful dial is in the Hong Kong University of Science and Technology. See www.fransmaes.nl/sundials, and in the Index choose H. In Google Earth, look at 22°20'16 N, 114°15'47 E. Have a nice trip! Frans Maes Douglas Bateman wrote: I am to visit Hong Kong next week for a 6 days and will naturally look out for sundials. I know of one already - a bronze armillary by Joanna Migdal at the Royal Hong Kong Golf Club in 1989. I would be grateful if anyone could let me know of other dials. Regards, Doug --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: God's Longitude and the Lost Colony of Virginia
Dear Roger, An intriguing story! Thank you for making this available to us all. What I wondered about: how accurately could longitude be determined around 1600? That problem was tackled only over a century later... Best regards, Frans Maes Roger Bailey wrote: At the BSS meeting in Cambridge this spring. Frank King outlined the problems assigning a unique date to a mark on a sundial. With our Gregorian calendar and leap year cycle the date for any given solar declination can vary over four days. He showed how a calendar based on a 33 year cycle devised by Omar Khayyam could reduce this spread to 24 hours. He then pointed out that for one specific longitude, the date of the first day of spring would always be the same. He mentioned that this was called God's Longitude and left it for us to figure out where that was as a homework exercise. I've done my homework and discovered a remarkable story, one that just had to be told at the NASS Conference in Virginia, at the 400th anniversary of the Jamestown colony of 1607. Fred Sawyer agreed to work with me as co-author and to present at the conference the story of God's Longitude and the Lost Colony of Virginia. It is a great story of the birth of science in Elizabethan England, the global conflicts of religion and empires and a secret agenda for the English protestants to occupy the new world at longitude 77ºW, God's Longitude. I have posted the presentation as Fred presented it at this personal website for you to download and enjoy. http://www3.telus.net/public/rtbailey/GodsLongitude/ It is a 5.7 MB PowerPoint presentation. If you do not have PowerPoint, download the free viewer from Microsoft. This will allow you to view the presentation but not the speakers notes that go alone with it. I would like to thank Frank King for the inspiration, Simon Cassidy for doing the historical research and uncovering the secret agenda, and Duncan Steel for publicizing it in his book Marking Time: The Quest for the Perfect Calendar. Enjoy, Roger Bailey www.walkingshadow.info http://www.walkingshadow.info --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Gatty's Book of Sun-Dials
Hi Fred and all, I recently bought the book. Unfortunately, it appeared to be a repriont of the 2nd edition from 1889, and not the 4th edition from 1900. So beware. Frans Maes Fred Sawyer wrote: Dialists who have always wished they could get a printed version of Mrs. Gatty's Book of Sun-Dials (the last and best edition came out in 1900) at a reasonable price will be interested to learn that the book has recently been reprinted in both paperback and hard cover editions by Kessinger Publishing LLC (specialising in reprints of rare books). To see both options on Amazon, try: http://www.amazon.com/Book-Sun-Dials-Collected-Alfred-Gatty/dp/other-editions/0548135649/ref=dp_ed_all/104-7954989-1105530?ie=UTF8qid=1190317403sr=1-23 http://www.amazon.com/Book-Sun-Dials-Collected-Alfred-Gatty/dp/other-editions/0548135649/ref=dp_ed_all/104-7954989-1105530?ie=UTF8qid=1190317403sr=1-23 Fred Sawyer --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Seasonal markers for Analemmatic Sundials
Dear Frank all, Frank King wrote: The expression now turns into a function of time: a . (coslat/cos(dec(t)) . sqrt(coslat^2 - sin(dec(t))^2) THIS is the expression to integrate over a whole year and whose average should be found. THAT result is where the markers should be placed. Now getting back to your initial question: What I want to know is where these markers should be placed... it seems to me that this expression calls for numerical integration, isn't it? Or in other words: The mathematics becomes cumbersome... Yes indeed! Interesting perhaps for the mathematically inclined, but remember that we were discussing APPROXIMATIVE sunrise/sunset indicators. I therefore would like to make a plea for the original Lambert circles. They are the real thing, no integration or approximation needed. The circle through any point of the date scale and the foci of the ellipse intersects the hour scale exactly at the times of sunrise and sunset for that date. One just needs a compass, or a pin and a piece of rope for a human-sized dial! An example of an analemmatic dial with a set of 7 Lambert circles (for the zodiacal months) can be found in Ootmarsum (NL). The dial was designed and constructed by Bote Holman. See my website www.fransmaes.nl/sundials, choose Index and browse to Ootmarsum, for pictures and details. By the way, the most elegant proof of the Lambert circles I know of has been given by Willy Leenders in Zonnetijdingen, the bulletin of the Flemish Sundial Society (in Dutch). Best regards, Frans Maes --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Sundial park in Ghent?
Dear Doug, I have to confess that my Genk site does not reflect the actual look of the Genk Sundial Park, as it is being reorganized right now. This implies the addition of a bicycle path (yielding a shortcut to the nearby Europlanetarium, www.europlanetarium.be). This necessitated the rerouting of some of the pedestrian paths. Unfortunately, some sundials are now under reconstruction, or are being approached from the wrong side, or are in death-end paths. We hope that the Genk authorities will soon make the necessary corrections to present this jewel of gnomonics adequately to the world to enjoy again! When in Genk, your friends should not forget to visit nearby (only 12 miles) Maastricht (or Maestricht as it is spelled in French :-), beyond doubt the prettiest city in the region! Best regards, Frans Maes Douglas Bateman wrote: Many thanks to Chris for the prompt reply. I have telephoned the information to the members concerned. Regards, Doug On Jul 21, 2007, at 18:13, Chris Lusby Taylor wrote: Hi Doug, It's Genk, not Ghent (which is Gand in Flemish and also spelt Gent, just to confuse the foreigner). Try http://www.fransmaes.nl/genk/welcome-e.htm Chris Lusby Taylor - Original Message - From: Douglas Bateman [EMAIL PROTECTED] To: Sundial List [EMAIL PROTECTED] Sent: Saturday, July 21, 2007 5:15 PM Subject: Sundial park in Ghent? Two of the BSS members are planning visit to Belgium and have heard that there is sundial park, but cannot find any information about it on the internet. Any advice or links will be appreciated. Many thanks, Doug --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Greek and Roman sundials
Hello Noam, The orientation of the gnomon rod (or even its shape or mere existence) is irrelevant. The time is read from the shadow of the gnomon TIP, in other words from an index or nodus point. A pole-style is only useful for showing EQUAL hours, as only the sun's hour angle is constant throughout the year. Hope this helps, Frans Maes Noam Kaplan wrote: Does anyone know if the Greek and Roman sundials would in actuality show what they are theoretically supposed to show in term of the unequal hours? The gnomon was either horizontal or vertical, not on an angle. Thanks, Noam Kaplan --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: strange longitude
Dear Frank all,
On the meaning of PI Long:
Waugh uses the symbol P in his computational treatment of the declining
dial on p. 80. The P values for each hour line in table 10.2 are what
Holwell (in Clavis Horologiae, London 1712) calls the polar angles. The
polar angle for noon equals the so-called difference in longitude DL.
Converted to time, this is the time of the sub-style line. So here is at
least a link between P and Long.
On the slight difference between the value PI Long = 35°43'40 and Fer's
value of 35.75° for the hour angle of the sub-style:
The equation for DL is: tan(DL)=tan(Dec)/sin(Lat).
The values given on the dial for DL and Lat are very accurate, down to
seconds of arc. The declination is merely given as 30°20' and thus seems
to be rounded, to perhaps 10 or 20 minutes of arc. The value actually
used for Dec can be calculated ('reverse engineered') from the equation,
yielding 30.3127° or 30°18'46. This value might have been the
calculated result of an actual measurement, perhaps involving the shadow
length of a rod perpendicular to the wall at noon. As the designer
realized too well that the accuracy of such a measurement is limited, he
put a rounded value on the dial.
Hope this helps,
Frans Maes
Frank Evans wrote:
Greetings fellow dialists,
John Foad has written to say that Keith Scobie-Youngs of the Cumbria
Clock Co, Dacre, Penrith, last restored the Hawkshead dial in 1997. He
asked the restorer if there was any clue from its original state, for
example whether any of the lettering had been uncertain. But Keith
Scobie-Youngs assured him that, though in poor condition, there was no
doubt about the previous inscription. He unfortunately had no
information or theory on what the PL Long meant, nor indeed as to why
the dial is canted to no apparently significant declination!
It has now been made clear to me by Fer de Vries, who has a good clear
photograph, that the letters PL that I cited are in fact PI.
Moreover his picture reveals the missing declining values printed beside
the locations values as Decl. 30 deg 20 min.
Here I take the liberty of passing on his message to me:
In the mean time I found a larger picture of this dial and there is
more text as you describe.
The part of the text I mean is in the attached picture.
A new value I read is: Decl 30 (degrees) 20 (minutes)
Now we are able to calculate all the constants of the sundial.
I get with ZW2000:
Style height30.19
Angle of substyle160.1 or 29.9
Hourangle of substyle-35.75
All decimal degrees.
I thought: bingo, hour angle of the substyle. But the value you
mentioned gives 35.7277.. decimal.
Still not all questions answered but perhaps this gives you another
idea how to solve it.
Well, this looks pretty close indeed and we may be nearing the answer.
Can anyone consequently suggest a relationship between the letters PI
and hour angle? Polar something? Moreover, actual longitude values
having proved pretty unlikely (problematic observatories in Brazil,
rural Russia, South Georgia, etc.) it is worth observing that actual
longitude values are not common on nineteenth century dials anyway.
Frank 55N 1W
---
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Re: Article in March BSS bulletin
Dear Chris, Bill all, I can add some information, based on my article on the Genk cone dial in the Bulletin of the Dutch Sundial Society, May 2005. Javier Moreno Bores mentioned the relationship between conventional hour lines and Bab. Ital. hour lines already in his article in the NASS Compendium 5(2), June 1998. The beautiful minimalistic sundial Chris mentioned is located in the Spanish sundial town of Otos (some 70 km south of Valencia). It was made by Joan Olivares (gnomonics) and Andreu Alfaro (artwork). A picture can be found at: http://www.ruralotos.com/ruta_rellotges.htm. Although it might look like an equatorial dial, it is in fact a horizontal dial. The hours are indicated on the concrete base: numbers for the even hours, points for the odd ones. The circle was mainly meant as an artistic addition. It does serve a calendrical function, though: at the equinox its shadow becomes a straight line. By adding hour and half-hour lines, and Bab. Ital. hour numbers, this nice sculpture could be converted into a triple sundial! Best regards, Frans Chris Lusby Taylor wrote: Thank you, Bill, for your very kind words. I'm glad my article hit the spot for you. I'm very fond of Italian Hours - one thing a sundial does a whole lot better than a watch is to tell you how long it is to sunset. The originator of the cone gnomon is, I believe, Javier Moreno Bores. I'd seen pictures of his dial at Genk. While working out how it must work, I realised (as he surely knows) that its hour lines are exactly the same as the half-hour lines of a conventional sundial. I also spotted that you don't need the whole cone - any conic section would be just as good. So a circular disk or ring surrounding a conventional gnomon would tell Italian and Babylonian hours on the existing hour lines. At that point, I remembered seeing somewhere a picture of a sundial with a gnomon consisting of a shiny metal tube that was bent to form both a polar gnomon and an equatorial circle. So, someone else seems to have had the idea of combining both gnomons on one dial before I did. Very sorry, but I don't know who. While thinking of other ways to realise the gnomon physically, I thought of using a CD. It turns out to be ideal, except for the hole in the middle, as its silvering helps you hold it at the correct angle. If anyone reading this is not a member of the BSS and would like a picture of my Universal Italian and Babylonian Hours Accessory consisting of nothing more than 3/4 of a CD, please email me off list. Please be careful not to email the whole list. Chris Lusby Taylor 51.4N 1.3W - Original Message - *From:* Bill CS.Com mailto:[EMAIL PROTECTED] *To:* sundial@uni-koeln.de mailto:sundial@uni-koeln.de *Sent:* Thursday, March 29, 2007 7:31 PM *Subject:* Article in March BSS bulletin I want to recommend Chris Lusby Taylor's article in the March BSS Bulletin on Italian/Babylonian hours and how they relate to the horizontal sundial. I had never really been interested in these hours much before, and did not understand the geometric principles involved. Chris's article took a little work for me to understand, but it was worth it, as the illustrations and text were right-on. I now understand how cone gnomons can naturally display these hours. Best of all, he describes a method for easily telling hours from sunrise, or hours to sunset, from a horizontal sundial, using just a (destroyed) round Music CD. Very clever. Chris, did you discover this method yourself, or is a modern day adaptation of a previously known method? Bill Gottesman Burlington --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Sundial pendant found
Dear all, The manufacturer of the sundial pendant is indeed Artissime near Nyons in the south of France. The even have a website: http://www.artissimesolaire.fr/ (French only). To see the yin/yang pendant, choose Bijoux, Les Optiques, and scroll about half-way down. Hans Scharstein (co-inventor of the Digital Sundial) forwarded my posting to Yves Opizzo (who together with Christian Tobin designed the well-known Sundial Garden in the Deutsches Museum in Munich). Yves told me that he designed the Saturn sundial years ago (why he called it that way will be clear when you scroll all the way down in the same Artissime page). Thus it is not a replica of an ancient example, and it has no esoteric background. Artissime developed many different trinkets based on this design, as the website makes clear. Jim Tallman is right in pointing out that this type of dial is not intended for equatorial use. As a horizontal dial, it measures azimut, so its accuracy is expected to be poor. Yves designed a larger and more accurate version, however, the LuxFlamma, which takes care of the time of year. It can be found in his website http://www.opizzo.de/ (in French and German). Click Suite Weiter, choose Cadrans portables / Tragbare Sonnenuhren, next Optique, Optische. It is an altitude dial. Apparently, the suspension point should be set to the time of year, and the time can be read from the corresponding date line. I think this is a very nice sundial type! The focus of a glass sphere is close behind the back, as in the Campbell-Stokes sunshine recorder. The exit point of the sunlight would thus be behind the mounting. Yves wrote me that it has a half sphere, however. The flat, polished side would reflect the sun rays internally, so that the light spot appears at the upper side (so I think it works). Clever! Thanks to Hans and especially to Yves for their help and information! Frans Roger Bailey wrote: Hello Frans, I have seen similar dials at sundials shoppes in France. I believe they are an Artissme product. They are based in Nyon and supply many shoppes in tourist areas (Briançon, St Veran, Bormes les Mimosas) with a range of sundials and related trinkets. Artissme has no web presence. I believe the design is artistic not gnomonic. There is no other reason for the ying yang dual dials that I can see. Roger Bailey N 48.6 W 123.4 A shoppe is boutique shop as in Olde Tyme Shoppe -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Frans W. Maes Sent: January 30, 2007 1:52 PM To: Sundial List Subject: Sundial pendant Hi all, Someone showed me the pendant in the attached photo. It seems to have two sundials in a kind of yin-yang arrangement. The glass beads focus the sunlight. When properly positioned (equatorial and the long arrow pointing south) the bright spot might show the hour. The diameter is ca. 30 mm. Can anyone shed some light on the origin or meaning of this double sundial? Why the anti-parallel arrangement? Why the different glass colors? Why the comma-like base for each? Thanks, Frans --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Sundial pendant found /2
I forgot to add that Joël Robic's picture shows the LuxFlamma even better! Frans robic.joel wrote: Hello Franz I agree with Roger, it seems to come from Artissime, you can see other examples (without yin and yang) from Briançon shop on the jpeg. And another similar one made by Yves Opizzo here : http://perso.orange.fr/cadrans.solaires/cadrans/images/IMG_1124.JPG Best regards Joël 48°01'25'' N, 1°45'40 O --- http://www.cadrans-solaires.fr/ --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Sundial pendant
Hi all, Someone showed me the pendant in the attached photo. It seems to have two sundials in a kind of yin-yang arrangement. The glass beads focus the sunlight. When properly positioned (equatorial and the long arrow pointing south) the bright spot might show the hour. The diameter is ca. 30 mm. Can anyone shed some light on the origin or meaning of this double sundial? Why the anti-parallel arrangement? Why the different glass colors? Why the comma-like base for each? Thanks, Frans attachment: pendant.jpg --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Place de la Concorde on Google Earth
Dear Willy and all, The hour lines still (partly) visible were laid out as a millennium project. An earlier project was started in 1939, but was interrupted by the beginning of World War II. It is interesting to note that some traces of those hour lines are still visible; in the attached picture part of the previously carved 11 hr line is seen some 30 cm to the right of the newer line. See the book Cadrans Solaires de Paris by Andrée Gotteland Georges Camus, or the website http://www.saf-lastronomie.com/csmp/ (look under 8th arrondissement). Is the difference due to a mistake in the lay-out of one of the line sets? No, the obelisk grew taller in the meantime! On 14 May 1998, the pyramidon that it once had in Egypt was replaced. A full-size model, serving as a plaque that memorizes this event, is mounted against the base of the obelisk. It is about 1 meter high. Of course, the old and new noon lines should coincide, but otherwise the new lines lie outside the old ones, seen from the noon (=meridian) line. See the book Cadrans Solaires de Paris by Andrée Gotteland Georges Camus, or the website http://www.saf-lastronomie.com/csmp/ and look under 8th arrondissement (both in French). Best regards, Frans Maes Willy Leenders wrote: More than once at this list the obelisk on Place de la Concorde in Paris and the sundial using the obelisk as the gnomon, was mentionned. On Google Earth, f ragments of several hour lines are visible as points on the car area and as lines on the pedestrian precinct of Place de la Concorde The intersection of the hour lines is a point at about 30.9 meter to the south of the base of the obelisk. That distance and the angles between the hourlines correspond to a nodal sundial at the latitude of Place de la Concorde (48.85 degrees N) using the 35.5 meter high point of the obelisk as node . On the picture (39 Kb) the f ragments of the hour lines are marked with red lines. Willy LEENDERS Hasselt Flanders (Belgium) attachment: XI-line.jpg --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Japan Sundial Society
Hi Joe, The URL of the Japanese Sundial Society is: http://www.ne.jp/asahi/sundial/hidokei/index.html I am sure their e-mail address is at the bottom of the main page :-) Best regards, Frans Maes newmail wrote: Friends, Do you know the electronic address of the Japan Sundial Society? Thank you for the reply. Best wishes. Joe --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: date scale
Hello Tracy, Sorry for jumping in so late. You like to have an analemma associated with the date line? There is a nice way, introduced by Marinus Hagen, founding father of the Dutch Sundial Society. See the small attached figure. One should stand right on the date line, as explained before. The analemma has a scale along the E-W axis, from which the EoT correction can be read. The large ticks are at 5 minute intervals. This is in fact an alternative for the use of a table or a separate EoT graph. Best regards, Frans Maes - Original Message - From: Tracy Paine [EMAIL PROTECTED] To: sundial list sundial@uni-koeln.de Sent: Sunday, October 29, 2006 10:52 PM Subject: date scale Hello Everyone I really like the drawing you made John for your customers - it helps a lot. Thank you. Thanks Tony for the picts and Powerpoint presentation - it is wonderful. Thanks Chi-Lian and Linda for your comments. After reading the advice I have received, I think that I will make my date scale the conventional way - although I think the analemma looks way cooler! It looks as if the first day of summer and the first day of winter are at each end of the scale. Is this true always? Also, does one stand directly on the centerline, or on the month block which falls to the left and right of the center line? More on my previous obsession of using the figure 8 in the date scale: If I am not mistaken, an analemma, on the ground for instance, can be made by marking the position of the sun (cast by some point) at the same time for a year every few days or so. I am referring to the website: http://www.cerrilloshills.org/analemma/path3.htm So, if I were to mark the path at noon, local time, for a year, the figure 8 should fall on the N-S line? It appears as though the months outlined on the figure 8 match the date scale in placement except at the top portion of the figure 8 where the months seem to flip from the left side to the right side. I can't help but think that the straight line date scale mimics the analemma in month placement. That's why I figured that I would make the figure 8 instead of the plane straight line. Also, I thought about positioning some type of gnomon that would cast a bright spot (or shadow) on the date scale which could follow the figure 8 path exactly (at noon) just like the noon analemma sundial featured in the website above. I am fascinated by the analemma and would love to somehow use it in my sundial, however, I definitely want my sundial to be correct and accurate - no false sundials here! But I keep seeing the analemma used as a date scale in pictures on the internet. One I found looks like it is bronze. If I shouldn't use the analemma in the date scale, where could I put it in the sundial properly? Or, should I just make a separate noon analemma sundial like that in the website referred above? --- https://lists.uni-koeln.de/mailman/listinfo/sundial hagen-analemma.gif Description: GIF image --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: a small analemmatic
Hi John, Roger all, Thank you, John, for the link, and Roger for the extensive, thoughtful comments. Wondering how small the sundial actually is, Mike Gaylard answered of the order of 1 metre. In physics this would be interpreted as: between 0.3 and 3 meter. Judging from the grass around the granite slab, however, the estimate looks quite close. As Roger pointed out, the analemmatic analemma in Mike's HartRAO website is used correctly, as it has its own EoT time scale at the bottom of the date line. I know of only one other such a correct usage. Marinus Hagen, founding father of the Dutch Sundial Society, constructed the first analemmatic dial of our country in his own garden. It also had an analemma around the date line with a separate EoT time scale. The attached schematic drawing (12 kB) is from an article he published in Zenit, an amateur astronomy magazine, in 1976. Best regards, Frans - Original Message - From: Roger Bailey [EMAIL PROTECTED] To: John Carmichael [EMAIL PROTECTED] Cc: [EMAIL PROTECTED]; Frans W. Maes [EMAIL PROTECTED]; [EMAIL PROTECTED] Sent: Sunday, September 17, 2006 5:33 AM Subject: RE: a small analemmatic Hi John, Thanks for the link http://www.nfi.org.za/palaeo/millennium_sundial.htm to the The Millennium Dial at Sterkfontein, South Africa. This sundial demonstrates well the shape and size of the analemma for the southern hemisphere at a latitude close to the tropic line. But, as usual for analemmatic dials with analemmas, this dial shows the common error of trying to use the analemma shape as an equation of time correction. The website tells the user to put the gnomon on date mark on the analemma to correct for the equation of time. This obviously only works at around noon when the correction is east or west. The north/south corrections required for the morning and afternoon go in opposite directions. This is not corrected with a single analemma. As Fred Sawyer describe in his article, Of Analemmas, Mean Time and the Analemmatic Sundial, at http://www.longwoodgardens.org/docs/analemma.pdf , a split dial with two analemma can be used with morning corrections on one analemma and afternoon corrections on the other. Brian Albinson demonstrated this well with his split analemma designs on the recent Vancouver Sundial Tour. Helmut Sonderegger's program ALEMMA available at http://web.utanet.at/sondereh/sun.htm calculates these split analemma dials well. The website http://www.hartrao.ac.za/other/sundial/sundial.html is referred to as the design basis for the Millennium dial. The designs by Mike Gaylard on this website show how the analemma can used correctly to account for the equation of time, but not directly. In his drawings,.the date line for the gnomon position is shown correctly by the green line at the N/S central axis. The red analemma shape shows the EQT correction for that date referenced to a small scale at the base of the dial. This is a clever way to include the EQT correction, but I do not see any evidence of such a reference scale in the Millennium Dial picture. Perhaps the correction scale should be added this and other dials that try to use a single analemma for EQT correction. This renovation may also provide a good opportunity to add Seasonal Markers. I have note yet seen these on a southern dial. It is interesting that many analemmatic dials in the southern hemisphere attempt to use a single analemma for EQT correction. I have seen such dials in Wellington NZ, Mt Annan NSW Australia and Kingston SE Australia. Click on the links below. There are others as well . often called the sundial of human involvement. Perhaps the latitude close to the tropics and compression of the hour ellipse makes the single correction appropriate. Perhaps it is the southern analemma with the big loop near the hour ellipse. Perhaps this was the design standard in 1990 when many of these dials were built. I don't know. There is a rationalization for the design in the book Sundials Australia by John Ward and Margaret Folkard. I read the description of the experiments and studied the drawings but I cannot agree that the single analemma gives an accurate EQT correction. Regards, Roger Bailey Walking Shadow Designs N 46.6 W 123.4 Northern hemisphere, well north of the tropics http://www.flickr.com/photos/glutnix/sets/151663/ http://www.rbgsyd.nsw.gov.au/mount_annan_botanic_garden/garden_features/buil dings_and_art/sundial http://walkabout.com.au/locations/SAKingstonS.E..shtml For a few of my scanned pre-digital pictures of our visits to two of these sites, to click on this Snapfish link. http://www2.snapfish.com/share/p=481161158454699242/l=211710424/g=56484356/c obrandOid=1000131/otsc=SYE/otsi=SALB -Original Message- From: John Carmichael [mailto:[EMAIL PROTECTED] Sent: September 16, 2006 7:35 AM To: Frans W. Maes Cc: Roger Bailey Subject: a small analemmatic Hello Frans, I came
Re: church interior dial
Hi Frank, In Roman Catholic churches I noted always 14 Stations, numbered I-XIV. Generally, they are placed symmetrically along the walls of the nave, thus nr. I-VII on one side and VIII-XIV on the other. Regards, Frans Maes - Original Message - From: Frank Evans [EMAIL PROTECTED] To: Sundial sundial@rrz.uni-koeln.de Sent: Wednesday, May 10, 2006 5:10 PM Subject: church interior dial Greetings fellow dialists, This is not really off topic, more off centre, perhaps. The church at Dalton-le-Dale, County Durham, England has what until now has been thought two dials. One is an important Anglo-Saxon dial of around 700 AD, mounted on a later wall. The other, the object of my question, is a series of numbers on the inside north wall of the nave of this thirteenth century church. Mrs. Gatty describes them incorrectly: There are some remains of a dial on an interior wall of St. Andrew's Church at Dalton-le-Dale; only the numerals I to VII are to be seen now, and these are raised in relief upon the plaster, and are said to conceal an older set of figures. The hours would be shown when the sun shone through the south window. There is a story currently told that the sun shone on the easternmost number on St. Andrew's saint's day, 30 November from a former hole in the roof. Given the low angle of the noon sun on that day this is quite impossible The numerals on the north wall of the nave are in fact VII to XII, not I to VII, arranged linearly from west to east and occupy most of the length of the wall at a height of about a metre. They were viewed by members of the British Sundial Society during their meeting in Durham a few weeks ago and the general consensus was that the numbers could not be any form of time measure. A proposal was that they had been placed under successive Stations of the Cross pictures and that they had survived where the pictures and the numbers I to VI on the south wall had not. My question is this: What is the history of Stations of the Cross in the Church of England. Presumably some must be pre-Reformation but they would generally have been extinguished by Cromwell's men and the puritan movement. Could the numbers have survived, without pictures, from the seventeenth century and a gradual story have grown up about their representing a sort of sundial? Speculation welcome. Frank 55N 1W -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.392 / Virus Database: 268.5.5/335 - Release Date: 09/05/2006 --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Conical Gnomon Advantages
Hi John all, I believe you absolutely when you told us: The shadow tests on the conical gnomon worked great even at low solar angles and I love the shadow cast by a plumbob. It is so dramatic and visible. What I wondered about is the following. When estimating the position of the plumbob tip from its shadow on the dial face, wouldn't that point shift towards the body of the plumbob when the distance gets larger? Intuitively I would expect the shadow of the tip to be 'eaten' by the fringe rays of the sun. Exactly the reason why pin-shaped gnomons (for instance the obelisk on Piazza Montecitorio, Rome) often have a little sphere on top... Whether the effect on time reading is at all noticeable, may depend on the specifics of the situation. So perhaps in practice it's not worth worrying? Another reason to rush outside to conduct an experiment! Regards, Frans Maes - Original Message - From: John Carmichael [EMAIL PROTECTED] To: Sundial List sundial@uni-koeln.de Sent: Wednesday, May 10, 2006 5:32 PM Subject: Re: Conical Gnomon Advantages I love these discussions that make you want to jump up from your computer, and rush outside to conduct an experiment! I used a CD white foamboard and I indeed saw the false ellipse of the projected solar image. Holding a 1/16 thick disk with a 1/4 hole about 3 ft. from the board and parallel to it, the fuzziness of the CD's perimeter shadow was very pronounced and the solar projection image was a long ellipse. As I rotated this arrangement, keeping the CD parallel, the solar image did disappear when the sun was almost edge on. (due to the thickness of the disk). So at these angles, the aperature nodus won't function. A conical gnomon won't do that. I compared the image of a conical gnomon (a plumbob) at the same distance, and I think it is easier to read. I love the shadow cast by a plumbob. It is so dramatic and visible. If you have a plumbob, check it out for yourself. They are cheap and come in different sizes and shapes. Almost all of them have a threaded cap for attaching the string. But you can remove and discard the cap and use the threads to attach it to a threaded rod which you can mount to the sundial face. Google: brass plumb bobs. Also try: weathervane finials Many thanks to all that have witten and for the drawings you sent. John C. - Original Message - From: John Carmichael To: Chris Lusby Taylor Cc: Sundial List Sent: Tuesday, May 09, 2006 11:54 AM Subject: Re: Conical Gnomon Advantages Hi Chris: But I'm not so sure I agree with you about a flat disk with a small hole. The aperture disk nodus you described works fine when the sun is not at low angles relative to the face. example: a direct south vertical wall dial around midday. But if it's early morning or late afternoon, won't both the shadow of the disk and the projected solar image elongate into long ellipses? In fact, if the sun is hitting the disk nearly edge on, I bet the solar image projection might disappear all together. If you could manually rotate the disk so that it is perpendicular to the sun, then I would agree with you. But sundial I'm designing is high above a doorway and can't be touched. Interested in anybody's comments on this, John - Original Message - From: Chris Lusby Taylor To: John Carmichael ; Sundial List Sent: Tuesday, May 09, 2006 11:00 AM Subject: Re: Conical Gnomon Advantages Hi John et al, If you want a circular shadow that doesn't elongate when the sun is at a small angle to the dial face, you can use a circular disc, held parallel to the plane of the dial. A large disc with a small circular hole in the middle works very well, too. The tip of a cone is an excellent idea, but I imagine it would only be practical for dials that are above head height, as the tip would seem dangerous otherwise. Chris 51.4N, 1.3W - Original Message - From: John Carmichael To: Sundial List Sent: Tuesday, May 09, 2006 5:12 PM Subject: Conical Gnomon Advantages Hello All; I have always been a big fan of spherical nodi on a perpendicular gnomons. I just like the way they look and when the shadow is only slightly elliptical, sundials with them are pretty easy to read. But in doing some shadow tests for a new wall dial I am designing, I was greatly dismayed by how much the shadow elongates when the sun is at a small angle to the dial face. The shadow ellipse is so stretched along the major axis that the dial would be very difficult to read. So, it occurred to me that a nodus that is the tip of a cone might be better. So instead of guestimating the center of an ellipse, you look at the shadow of the point of the cone. (To test this, I attached a brass conical plumbob to a threaded brass rod). I figured that a cone would work better than a flat arrow because it has a uniform cross section around it and
Re: Buyer's Guide
Dear Mike all, The most popular garden-center sundial around here is the armillary sphere. They always read local solar time. Stimulated by questions of (prospective) buyers, I once tried to write a fail-safe, fool-proof instruction for correct installation. There are differences with horizontal dials, of course, but most aspects are common to both. Therefore I would like to tell my doubts about the feasibility of such instructions. I stopped my attempt, when I got frustrated by thoughts like: would any layman-reader be able to find his latitude, or even know what latitude means? Would he know how to measure and check an angle? Absolutely not trivial! But the most bothering aspect was: how to instruct setting the correct orientation? That aspect is missing from your 'golden five'. The pole-style, or gnomon sides in your case, should point to Polaris. Ever tried directly? The method I would use myself (after having checked the earlier aspects) is: calculate local solar time from clock time by taking latitude correction, EoT and DST into account, and turn the sundial until it reads local time. How to explain this procedure and its rationale unequivocally within 2-3 sentences? Providing insight in the relation between local and clock time is the more important, as the correctly oriented sundial will henceforth read local time. In Western Europe the difference with clock time is large, so that it is useless as a clock to the non-insider. Which makes the artistic quality the most important property to most people... I ended up with only a couple of hints on the Dutch version of my sundial site: - Don't take souvenir-type vertical dials from southern Europe back home - Check if the insertion point of the style is on the 6-18 hr line (for horizontal dials) - Are adequate instructions for installing and orienting the dial included? - Can it be fixed good enough so as not to serve as wind vane or merry-go-round? - Is the material weather-proof? - Doesn't it collect rain that turns into a swamp (except for the bird-bath type)? Have other list members experience with writing general instructions? Regards, Frans Maes - Original Message - From: Mike Shaw [EMAIL PROTECTED] To: Sundial List sundial@uni-koeln.de Sent: Friday, May 05, 2006 9:20 AM Subject: Buyer's Guide Fellow enthusiasts, I get really annoyed about the sundials that I see on sale in garden centres here in the UK. The people who make them seem to have no conception about how they work. As they are invariably horizontal dials, I thought I would put a Buyer's Guide to such dials on my web site. I think there are 5 golden rules - have I missed any? Check it out - follow the link from my home page. Helpful comments welcomed. Mike Shaw 53.37N 3.02W www.wiz.to/sundials --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: high-latitude dial
For an equatorial dial with a square gnomon giving rise to four pole styles, go to www.fransmaes.nl/sundials, click Pole style - equatorial and then the first thumbnail in the page. Interestingly, the two sides of the dial face have been relocated so as to avoid kneeling down in fall and winter. Regards, Frans - Original Message - From: [EMAIL PROTECTED] To: sundial@uni-koeln.de Sent: Wednesday, March 15, 2006 7:20 PM Subject: high-latitude dial This is really a gedanken experiment as I know no one at high latitude needing a dial, but here's what I came up with for a dial primarily for high latitude. The dial has a square gnomon and four sets of hour lines, one set for each style. I'd be interested in the list's comments on its practicality. Last time I had an idea, I was told by the list that the dial was invented in 832 BCE, and approximately 400,000 have made each year since then. No, seriously, I'm naturally curious if it's already been done. After drawing this, I googled square gnomon and got one hit - from one of the list's own luminaries, John Carmichael! So something like the idea is out there, at least. Thanks, John --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Is it possible to determine when the sun is due East West?
x-charset utf-8Hi Alexei, In addition to the common horizontal and vertical types, you may find pictures of equatorial, polar, spherical, polyhedral, nodal, meridian, bifilar, shadow plane, conical and digital dial in my sundial site: http://www.fransmaes.nl/sundials - Original Message - From: Alexei Pace [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Saturday, September 17, 2005 8:05 AM Subject: RE: Is it possible to determine when the sun is due East West? On another topic, does anyone have a photo gallery of any new sundials , preferably something ���innovative��� not just a gnomon in the wall type of sundial.. Regards, alex _ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Th. Taudin Chabot Sent: Is-Sibt, 17 ta' Settembru 2005 07:58 To: sundial@rrz.uni-koeln.de Subject: Re: Is it possible to determine when the sun is due East West? David, If this group has religious duties to pray due East or due West then that religion must halso have the means to determine that direction, you see that in any culture in the world. So I wonder how they found those directions before. It is more or less the same question I had earlier (and still have): how did the ancient people at the building of Stonehenge find the equinoxes? Thibaud Chabot - /x-charset
Re: cuboctahedron
Hi David, I am interested in polyhedron dials. What is a cuboctahedron? A cube with the 8 corners cut? That would leave 6 octagons and 8 triangles. Regards, Frans Maes -
Re: The sundial of Emperor Augustus - english translation
Dear Nicola and all, Thanks to Jack Aubert I can respond to your posting. I often regret being unable to read Italian or Spanish, as so many important gnomonic publications appear in these languages! The primary aim of my article on the sundial of emperor Augustus was to bring the important paper by Michael Schütz (published in 1990) to the attention of the gnomonic community. In addition, I reviewed the further goings of Buchners story. Around 1980, prof. Edmund Buchner excavated part of a meridian line constructed a century after Augustus erected an Egyptian obelisk in the Mars Field in Rome. He hypothesized that Augustus constructed a huge sundial and argued that a centimeter-precise topographical relationship existed between the sundial and the nearby Ara Pacis (peace altar). Schütz showed that Buchners assumptions on the height of the obelisk were mostly unjustified and that his calculations of the position of the obelisk and the sundial layout were incorrect. Schütz' paper (in German) apparently was unknown in gnomonics, so that Buchners speculative hypothesis was considered a proven fact. The only author who knew Schütz article (and agreed) was Karlheinz Schaldach. The bird's eye perspective argument comes from his book on Roman sundials. Schütz is is also missing from the bibliography in your 1997 article (which I downloaded but unfortunately cannot read). When I contacted you last November to get your opinion on Schütz' criticism, I was very sorry that the language problem prevented a fruitful communication. Still, I am looking forward to your evaluation of Schütz' - in my view convincing - arguments. Best regards, Frans Maes -
Re: Armillary Dial
Dear Heiner all, Dials such as the one in Pompeii were more common in the Roman world than the obelisk-type dials, I think. I have written a paper on the origin of the pole-style principle in the Bulletins of the Flemish and the Dutch Sundial Societies (2003-2004). My conclusion was that the pole-style appeared in the Western world around 1400 in Germany. Zinner found a manuscript dated 1430, giving instructions for laying out the hour lines of vertical pole-style dials. He also found a mention to a diptych dial from 1417. The oldest still surviving, dated pole-style dial appears to be the one at the church of Weissenfels (Germany, near Leipzig). With respect to a possible Arabic connection, Len Berggren (NASS Compendium June 2001) wrote: By the end of the tenth century Muslim scientists had invented the polar dial, the equatorial dial, and the horizontal dial with the gnomon parallel to the polar axis, referring to studies by David King. The suggestion that the pole-style principle might have been imported in the West by returning crusaders was discussed and rejected by Karlheinz Schaldach in BSS Bulletin 1996 (3). Armillary-type astronomical instruments were used by the Greek already, such as Ptolemy (2nd c. AD). Armillary spheres, as navigational instruments, were the basis for the Portuguese maritime expansion in the 15th century, as was illustrated by Roger Bailey in a talk at the 2001 NASS conference. I have been unable to find when armillary spheres were first used specifically as clocks. Best regards, Frans W. Maes 53.1 N, 6.5 E www.fransmaes.nl/sundials/ - Original Message - From: heiner thiessen [EMAIL PROTECTED] To: 'Sundial Mailing List' sundial@rrz.uni-koeln.de Sent: Wednesday, July 13, 2005 7:20 PM Subject: Armillary Dial After Roman dials with their vertical obelisk type gnomons, when did sundials with gnomons in parallel to the planet's axis first appear? I found an entry in the BSS Glossary 2000 for the introduction of an armillary dial in 1598 by Valentin Pini. Would he have been the first one to have installed a 'modern' dial? Is there a history of the development of the dial ? Best wishes Heiner Thiessen 51N1W -
URL changes
Hi all, Due to problems with my previous web host, I had to move my sundial sites to a new hosting service. The old site does not even provide a redirection notice. Please update your bookmarks / favorites. Zonnewijzers/sundials (Dutch English): www.fransmaes.nl/zonnewijzers/ Shortcut to the English version: www.fransmaes.nl/sundials/ Sundial Park Genk, Belgium (Dutch English): www.fransmaes.nl/genk/ Sundials in Torreón, Mexico (Spanish English): www.fransmaes.nl/torreon/ Thanks, Frans -
Re: On the greatest size of an analemmatic
Hi Anselmo all, In my webpage www.fransmaes.nl/sundials/ - Analemmatic - extra info - The human scale, I calculated the shadow paths for a 2 meter gnomon (human with hands above head) in dials of 6 and 10 meter major axis, for latitudes of 35, 45 and 55 deg. I find it no problem to extend the symmetry line through my shadow accurately by half my height (the summer case). In fact, I find it more difficult to make an accurate reading when my body's shadow (in winter) is falling on the ellipse. From my graphs and these considerations, I would say that 7 meter is about the maximum. When you set the date scale on a 30 cm step, you could add 15%, making 8 m (25 ft) the maximum. Best regards, Frans Maes - Original Message - From: anselmo [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Friday, April 08, 2005 8:23 AM Subject: On the greatest size of an analemmatic Dear all, I need your opinions and advice on which could be the greatest *effective* size of an analemmatic sundial for average latitudes. As you all know, for latitudes about 40 deg, the least longitude of the style equals more or less the major semiaxis of the ellipse so that the shadow can reach the ellipse on the worst case, this is, at summer solstice noon. However, in practice it could be too conservative to suppose so (who, except us, stands on an analemmatic in the worst of summer?), and perhaps there are some practical rules you know... Any hint? I am considering that the date scale can be on a 30 cm high step where the user gets up to and that the user can rise his/her hand so that the effective height of the style could be around 220 cm or so. Best regards, Anselmo - -
Re: Sundial Cupolas
Hi John all, Only after I saw the cupolas in your links, I understood that these were not dome-shaped, but square. I found some examples in the Netherlands, which I put temporarily on my website, at: www.fransmaes.nl/sundials/cupola.htm . You surely will show us the results of your enterprise? Best regards, Frans - Original Message - From: John Carmichael [EMAIL PROTECTED] To: Sundial List sundial@rrz.uni-koeln.de Sent: Saturday, March 19, 2005 6:55 PM Subject: Sundial Cupolas Hello All: I'm considering building or buying a four-sided painted wood cupola with a copper roof for the roof of a home. I'd like to put a sundial on each face of the cupola and then a neat weathervane on top. I've had great fun searching for cupolas and weathervanes online. There are and endless variety of styles and available. Most of the companies that sell cupolas also sell weathervanes. Here's a photo of one of the windcup weathervanes I like: http://weathervanesofmaine.com/weathervane-wc9821.html And I'm thinking of a cupola that would look something like this (Glassed Mahogany Pagoda with 701 Finial Image 2), but with sundial faces instead of windows: http://www.weathervanecupola.com/cat/cupolas.html Have any of you ever seen a cupola or clock tower with sundials instead of clocks? John p.s. Do you think the copper weathervane will act like a lightning rod? Maybe it should be grounded? p.p.s A lot of the weathervane websites sell marvelous copper finials that a dialist could use for perpendicular gnomons. -
Archive?
Dear sundial friends, I lost last year's sundial list messages, due to some mishap with our new e-mail server. As far as I know, the list is not officially archived. Has anyone perhaps collected the postings from 20 Jan. 2004 to 19 Jan. 2005? Please mail me off-list before sending :-) Thanks! Frans -
Re: Earliest Sundial
Dear Mike, Hal and all,
I am sorry that I could not respond earlier to Mike's posting.
Last year I wrote an article about a related question, from which I have
some relevant information, perhaps also for Hal :-)
1) The earliest evidence for pole-style dials in Europe.
The only author who did extensive research in archives of monasteries,
libraries etc. is Zinner, I think.
Zinner (in Deutsche und Niederländische Astronomische Instrumente des
11.-18. Jahrhunderts, 1956, p.55) mentions a folding sundial from 1417. He
refers to his book Die Frankische Sternkunde im 11. bis 16. Jahrhundert
(1934, p. 56), which I just got from the library. He quotes Georg Hartmann
(instrument maker and researcher in Nuremberg), who wrote in 1544 that he
received this sundial from Duke Ott-Heinrich, dated 1417, who ordered a
copy. It was a cross dial; the cross unfolded in the equatorial plane, so
that its edges pointed to the celestial pole. How reliable the quoted date
is? Zinner refers to a book of collected letters, edited by Johannes Voigt
from 1841, which I don't want to go after...
Zinner (1956) found manuscripts giving instructions for the construction of
pole-style dials from 1426 onward. So my conclusion is that the pole-style
principle appeared in Europe around 1400.
2) The Arabic connection.
The sundial at the Umayyad mosque in Damascus from 1371 (mentioned in
earlier postings) has been described by Louis Janin in Centaurus 16 (1972),
p. 285-298 (including a photo). It incorporates three sundials. The one for
equal hours uses a pole-style. It is a high-point of Arabic gnomonics, and
apparently the result of a long tradition. So the pole-style principle was
known to the Arabs long before 1371, but was only used by astronomers.
The odd story of this sundial: the Egyptian astronomer At-Tantawi noted in
1876 that it was not level and not properly aligned anymore. When he tried
to correct this, the marble dial face (1x2 meter) broke. He made a copy,
which is quite accurate, as is apparent from comparison with three large
pieces of the original. These are now in the National Museum in Damascus.
3) Was the pole-style principle brought to Europe from Arabia, for instance
by returning crusaders?
Karlheinz Schaldach, in BSS Bulletin 1996 nr. 3, p. 32-38, thinks not. He
gives 3 arguments:
a) The first Latin author (or at least one of the first) writing on the
construction of equal-hour sundials, gives no hint that he obtained any
ideas from Islamic contemporaries.
b) There are almost 100 texts on sundials of the 14th and 15th centuries,
proving a great effort in understanding sundial principles, but none giving
the correct solution of the pole-style.
c) There are some 'sun-trials' from that period, showing a 'trial and error'
process.
4) What is the oldest still existing pole-style dial?
a) Fixed dials.
My article addressed the question: What are the oldest, dated or datable,
fixed sundials? It appeared in the Bulletin of the Dutch Sundial Society
2004 nr. 1, p. 15-18, and nr. 2, p. 25-29. The focus was on the sundial at
St. Jacob's Church in Utrecht (NL), which is dated 1463. Zinner, in his
extensive catalog Alte Sonnenuhren an Europaeischen Gebaeuden (1964) gives
in the introduction a list of 27 modern sundials of the 15th century. With
'modern' he means reading equal hours, which implies a pole-style. Utrecht
is nr. 7 in this list. With help of Karl Schwarzinger, who takes care of the
Austrian database, and Willy Bachmann, who maintains the database of German
sundials, I was able to check the list, remove some and add some others, and
to get pictures of each. My list of the six oldest dials is as follows:
1446, Weissenfels (Germany), stone-carved, dated
1447, Klosterneuburg (Austria), stone-carved, dated
1452, Hall (Austria), painted, datable
1454, Waldhausen (Austria), stone-carved, dated
1457, Duderstadt (Germany), stone-carved, dated
1463, Utrecht (Netherlands), stone-carved, dated.
'Datable' means: a reliable written source exists, and the stylistic
appearance of the sundial fits the period.
The list should be considered with some reserve, though. Dated medieval
sundials (with a horizontal rod as gnomon) may have been upgraded to a
pole-style dial later, or the carved date may have been changed at later
restorations. Perhaps antedated, to impress neighbouring parishes? Also,
documents may surface some day documenting an earlier date for as yet
undated dials.
b) Portable dials (travel or table-top).
I have not researched this question. Karl Schwarzinger sent me a pretty
folder with color pictures of many beautiful Austrian sundials. Among these
is a folding dial ('Klappsonnenuhr') from 1451, possibly made by Georg
Peuerbach and now in the Kaiser Maximilian Museum in Innsbruck. Does anyone
know of an older portable dial?
Best regards,
Frans Maes
53.1N, 6.5E
www.fransmaes.nl/sundials/
- Original Message -
From: [EMAIL PROTECTED]
To: sundial@rrz.uni-koeln.de
Sent: Monday, January 17, 2005 11:19 PM
Re: 'Wineglass' of Sonius
Dear Peter, You are correct. My statement One could imagine that a dial with an identical dial face is constructed for use in Australia is too optimistic. Of course you can retain the overall tree shape. Sorry for the confusion! Regards, Frans - Original Message - From: Peter Mayer [EMAIL PROTECTED] To: Frans W. Maes [EMAIL PROTECTED] Cc: sundial@rrz.uni-koeln.de Sent: Monday, November 22, 2004 12:14 AM Subject: Re: 'Wineglass' of Sonius Dear Frans, The 'Tree of Sonius' is basically not a vertical pole-style dial, but a shadow plane dial. You are therefore free to arrange the hour lines any way you like. So you might as well retain the tree shape. See the entry #11 in my website on the Genk Sundial Park: www.fransmaes.nl/genk/ . Thanks for your acute comment and the super photos on your website. You are of course correct that since it is a shadow plane dial, the lines can be moved about. But: am I right that they must nevertheless remain parallel to those of a vertical dial? If I adopted the boom/baum/tree format for Australia, and want it to be read, as is the Limburg dial, from 'left to right', won't the hour lines 'converge' on a point above the tree? Or have I missed something quite fundamental? Thanks for your help, Peter -- Peter Mayer Politics Department Adelaide University, AUSTRALIA 5005 Ph: +61 8 8303 5606 Fax : +61 8 8303 3446 e-mail: [EMAIL PROTECTED] --- This email message is intended only for the addressee(s) and contains information which may be confidential and/or copyright. If you are not the intended recipient please do not read, save, forward, disclose, or copy the contents of this email. If this email has been sent to you in error, please notify the sender by reply email and delete this email and any copies or links to this email completely and immediately from your system. No representation is made that this email is free of viruses. Virus scanning is recommended and is the responsibility of the recipient. -
Re: 'Wineglass' of Sonius
Peter, The 'Tree of Sonius' is basically not a vertical pole-style dial, but a shadow plane dial. You are therefore free to arrange the hour lines any way you like. So you might as well retain the tree shape. See the entry #11 in my website on the Genk Sundial Park: www.fransmaes.nl/genk/ . Regards, Frans Maes - Original Message - From: Peter Mayer [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Friday, November 19, 2004 4:32 AM Subject: 'Wineglass' of Sonius Hi, I've been thinking for some time about making dial on the model of the Tree of Sonius in Limburg, Belgium (see Karl Schwarzinger's great homepage: http://members.tirol.com/k.schwarzinger/b_5650.htm for a picture of the dial and a very clear diagram illustrating the principle of the dial. Thanks Karl!). Since my model will be for the southern hemisphere, but is to be read 'left to right' it will have to be 'bowl-shaped' (or as I prefer to think of it, 'wineglass-shaped'!) rather than 'umbrella-shaped' as is the Limburg original. My question to the group is: what is the simplest, most sensible way with a modest kit of hand/power tools to cut the complex shadow plane slots for each hour? My present thinking suggests i) drawing a normal vertical dial for my location on the north face, then ii)'extending' the angle of the style (from the 6 o'clock line) across the side of the block which constitutes the dial and using the intersection of the style extension with the south side of the block to position and draw a second vertical dial--a mirror image, of course. Step iii) is to connect the respective hour lines on the two faces across the edges. Step iv) would be to successively align the block so that each hour plane is vertical and use a mitre box to cut the shadow plane slots. Since Fer de Vries co-designed the original, I'm sure he'll have a far more sensible plan! (How on earth was it done in stainless steel??) Many thanks, Peter Mayer -- Peter Mayer Politics Department Adelaide University, AUSTRALIA 5005 Ph: +61 8 8303 5606 Fax : +61 8 8303 3446 e-mail: [EMAIL PROTECTED] --- This email message is intended only for the addressee(s) and contains information which may be confidential and/or copyright. If you are not the intended recipient please do not read, save, forward, disclose, or copy the contents of this email. If this email has been sent to you in error, please notify the sender by reply email and delete this email and any copies or links to this email completely and immediately from your system. No representation is made that this email is free of viruses. Virus scanning is recommended and is the responsibility of the recipient. - -
Re: italian dial
Hi all, I had the same question three years ago. After consulting some Italian sundial contacts, Gianni Ferrari provided the solution: .. The strange dial is one of five works that the municipality has ordered in 1994 to five artists in the intent to give life to a project of museum of modern art, open air. The quadrant has been realized by the artist Giulio Paolini and, according to the words of the author: The project intends to propose the realization of a sundial of the dimensions and in the place (the external wall of the church of Sant'Agostino) where an ancient sundial was. A geometric motive (the profiles of the planets or their orbits) and a sketch are engraved on the surface to plaster. There is also the sentence TOUT SE TIENT [everything hangs together, FM] that signals the four cardinal points with four of the letters that compose it. A pencil, in bronze, is fixed in the central point perpendicularly and it projects its shadow on the whole sketch. It is a pity that the new quadrant is completely false and wrong as sundial, doesn't have anything to do with gnomonics and has been superimposed to an authentic old solar clock. .. In addition to Gianni's complaint, the title of the artwork is also quite peculiar: Meridiana. On request I can send you a picture of the work, and an enlargement of the 'dial face' (some 20 KB each). Best regards, Frans Maes - Original Message - From: Frank Evans [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Sunday, August 08, 2004 2:37 PM Subject: italian dial Greetings fellow dialists, Can anyone please help me to decipher this: I have been sent a picture, by a friend, of an Italian presumed dial on the wall of Sant' Agostino church in San Gimignano, Tuscany. It has a horizontal gnomon which is a simple shaft. Around it are drawn eight circles which are not concentric but each touching the next circle outwards at one point, mostly horizontally, alternatively left and right but the inner circles touching at 45 degrees to the horizontal. Additionally there are two rather flat ellipses drawn obliquely round the centre point. What I take to be cardinal points, the letters N, S, E and O are marked as well as the intercardinals E, T and C (nothing for south-east). My friend writes that the dial faces roughly south south east. There are no hour marks. My picture is a close-up and I am unable to guess a scale. I am totally baffled. Any suggestions? Frank 55N 1W -- Frank Evans [EMAIL PROTECTED] - -
Re: Place de la Concorde
Hi John all, The nail heads you saw are not from the reconstruction of the Paris meridian by the Dutch artist Jan Dibbets, as this runs through the Observatory of Paris and passes through the Louvre Museum, a kilometer or so east of Place de la Concorde. See http://www.amb-pays-bas.fr/fr/ambassade/pcz/arago.htm for info on that captivating project (in French). Instead, the nails are from the millennium sundial, inaugurated in 1999. I have put some pictures at www.fransmaes.nl/concorde/concorde.htm to illustrate Willy Leenders' posting (5 pictures, some 280 KB in total). Best regards, Frans W. Maes - Original Message - From: Willy Leenders [EMAIL PROTECTED] To: John Carmichael [EMAIL PROTECTED] Cc: sundial@rrz.uni-koeln.de Sent: Tuesday, August 03, 2004 12:58 AM Subject: Re: On northern vs. southern dials Hello John; At the website http://www2.iap.fr/saf/csmp/arr8n/centrea84.html you can find a text and photographes that gives perhaps the answer to your question. I translate briefly in bad English the French text. En 1913, l'astronome Camille Flammarion, fondateur de la Société Astronomique de France, proposait à la Ville de Paris de tracer sur la place de la Concorde les lignes du plus vaste cadran solaire du monde. La guerre de 1914 n'a pas permis de réaliser ce rêve The astronome Camille Flammarion proposed in 1913 a sundial on the Place de la Concorde using the shadow of the obelsik (one of the two obelisks at the temple of Luxor built by Ramses II 1250 B.C.). The 1914-1918 war prevented the realisation. En 1938, Daniel Roguet, architecte DPLG, architecte de l'Observatoire de Juvisy, membre du Conseil de la S.A.F, avec la collaboration des Ingénieurs et Géomètres de la Ville de Paris et du Service Géographique de l'Armée, reprend le projet de Flammarion. The project of Flammarion was retaked by the architect Daniel Roquet in 1938 in collaboration with a team of engeneers and surveyors of the city of Paris and the geographic services of the army. Les travaux sont commencés au printemps 1939, mais interrompus par la guerre de 1939-1940. The execution of the project began in 1939 but was interrupted by the 1939 -1945 war. Les traces du cadran, commencé en 1938, sont visibles : creusées dans le sol de la chaussée qui entoure le parterre au Sud de l'obélisque. 5 lignes horaires devaient aboutir à des plots en bronze portant les indications des heures et des saisons. The traces of this sundial are still visible: 5 hour lines with bronze marks provided with hour and season indications (perhaps the humps you have seen). Un nouveau projet de Philippe de la Cotardière et de Denis Savoie, Président actuel de la Commission des Cadrans Solaires de S.A.F. L'inauguration du cadran solaire a eu lieu le 21 juin 1999 A new poject of Philippe de la Cotardière and Denis Savoie is executed and inaugurated the 21th of june 1999. Lorsque la pointe de l'ombre passe sur une ligne horaire, matérialisée sur le sol, il suffit de lire l'heure indiquée à l'extrémité de la ligne. The sundial is a nodal sundial. The end of the shadow of the obelisk indicates on a line placed in the pavement the hour indicated at the end of the line. * In august 2003 I saw the sundial. On the meridian passing through the footh of the obelisk (the XII hour line) there is on a disc the inscription AU LEVANT DE THEBES SURGIT A PARIS LE NORD. I translate this as AT THE EAST OF THEBES THE NORD RISES IN PARIS. Nobody, nor Denis Savoie, can explain this sentence. I can send a jpeg-picture of this disc with inscription if desired. Willy Leenders Hasselt, Flanders in Belgium 50.9 N 5.4 E John Carmichael wrote: Hello Jean-Paul When I went to Paris after the Oxford conference, we were driving around the Place de la Concord in a taxi and I noticed several little (about 10 -15cm) round brass mounded humps inlaid in the asphalt. We were going to fast to see if there was anything written on them. I immediately guessed that they might be hour or date markers for the sundial. Has anybody else seen these mysterious little brass markers there? John - Original Message - From:Jean-Paul Cornec To: Sundial, Mailinglist Sent: Sunday, March 03, 2002 5:41 AM Subject: Re: On northern vs. southern dials Anselmo The sundial on the Place de la Concorde in Paris is a classical horizontal sundial with the Obelisque as a vertical gnomon. Lines are now more or less erased due a lack of maintenance. There was a scheme with a short explanation in the june 1999 issue of L'Astronomie. I can scan it and send it to you or to any member of the list; just send me a mail. Regards Jean-Paul Cornec (...) Now that I remember, a kind of touristical question: in this month's issue of the spanish version of Scientific American there is an articleby D. Savoie about sundials an in it he says
Re: EOT + Longitude Correction Table
Hi all, Returning from holidays, I drop in a little late, I know. Johns intention makes good sense and is absolutely worthwhile. Just one additional advantage of listing/graphing the combined EoT+longitude correction may be mentioned. For sundials which are more than 4 degrees away from the standard meridian, the correction has the same sign all year. In much of continental Western Europe, for instance, the clock is always ahead of the sun. This avoids the addition or subtraction of negative correction values, which otherwise puzzles most people (including sundialists!) Best regards, Frans Maes 53.1 N, 6.5 E www.fransmaes.nl/sundials/ - Original Message - From: John Carmichael [EMAIL PROTECTED] To: Sundial List sundial@rrz.uni-koeln.de Sent: Thursday, July 08, 2004 6:44 PM Subject: EOT + Longitude Correction Table Hello All, Some of you wrote me and seemed very confused with my inquiry about a way to get a EOT table that is longitude corrected. You ot understand what I wanted. So I'll try to explain it here. (thanks to everybody who sent me info on this) Sample letter: I still cannot figure out your EoT problem; EoT does not depend on longitude, it depends on an agreed absolute (GMT) and changes so little in any time zone you cannot see the difference on a dial. Maybe I am missing something, I often do these days. Yes, you are missing something. And it's so simple you will kick yourself. You're thinking too deeply! I'll try to explain... Of course you are correct in implying that EOT values are Universal and are basically the same all over the world, at any longitude or latitude and on any given date. You can use the same EOT graph with almost any sundial anywhere in the world. But you know that already. So far so good. But if somebody really wants to know clock time, then not only does he have to correct his sundial readings for EOT, but he also has to correct for his longitude (and Daylight Saving Time if applicable). This additional longitude correction is expressed as a plus or minus value in minutes and seconds. But you know this already. So far so good. Now this double correction is sometimes confusing to non-dialists (it's a triple correction if one has to correct for Daylight Savings too). So to reduce two time reading corrections into just one correction, you can add the EOT correction to the longitude correction since both expressed in minutes and seconds, and you come up with a new EOT graph or table that incorporates the longitude time correction in its values. Now do you get it? Neat huh! For my sundial customers, I usually build the longitude correction directly into my sundial faces so the customer doesn't have to do the longitude correction, just the EOT correction. This combined EOT+Longitude Correction Table is very useful if you have an antique pre-timezone sundial or any sundial that doesn't have a built-in longitude correction. The downside is that you have to make a unique customized EOT table for each sundial, depending on its particular longitude. Hope this helps - -
Re: Photographing Sundials
Dear John, With respect to your third point: A well-known trick to avoid text on the back of a photo (or book page, etc.) to 'seep through' into the scan, is to place a sheet of black paper behind the photo or page. The result may get a little darker overall, but that can easily be corrected by the brightness control in the image processing program. Regards, Frans Maes - Original Message - From: John Carmichael [EMAIL PROTECTED] To: Sundial List sundial@rrz.uni-koeln.de Sent: Thursday, April 29, 2004 4:52 PM Subject: Photographing Sundials Hello All, Thanks to the wonderful BSS conference in Oxford, people have been sending me new photos of spectacular unknown (to me) stained glass sundials. Some are on enormous church windows and are just stunning in their beauty. But I just have to right this letter. While I'm extremely grateful and appreciative of any photos people send me for our Image Archive, it is so disheartening that the photos are often of such poor quality. Of course I'm very happy to have them (a poor photo is better than no photo). But there are some simple things that the photographers can do minimize the poor quality. 1. First of all, the biggest mistake that people make when they take their pictures is that they don't hold their camera straight and the photograph comes out crooked. 2. The 2ond big mistake is that the subject of the photo is not completely contained in the frame and the sundial's image gets chopped off on one side. Either zoom out on your telephoto or step back to increase the distance to the subject! Many of the photos I get suffer from both these problems: They are crooked and chopped off. 3. If you have prints made of your photos: Do NOT write on the back of them, especially with a ball point pen! Felt tip are even worse. This often is visible on the photograph when I scan the print!!! I don't want my letter to discourage people from sending me copies of their photos, I'm just trying to educate everybody so that we get better photos in the future. The BSS and NASS have the same problems with many photos on their sundial registries. thanks for hearing me out on this. p.s. If you want to take REALLY good photos then use a tripod and try to center the camera as close to directly in front of the sundial as possible (hard to do with tall dials, I realize) John L. Carmichael Jr. Sundial sculptures 925 E. Foothills Dr. Tucson Arizona, 85718 USA Tel: 520-696-1709 Email: [EMAIL PROTECTED] Sundial Sculptures Website: http://www.sundialsculptures.com Stained Glass Sundials Website: http://advanceassociates.com/Sundials/Stained_Glass - -
Re: PowerPoint Setup
Hi John, Don't print out 65 pages of paper prints, one for each slide. Instead, go to File - Print. Under Print what, choose Handouts. In the box Handouts, choose Slides per page: 3. Next to each slide you will get space to write your notes. Frans - Original Message - From: John Carmichael [EMAIL PROTECTED] To: Alexei Pace [EMAIL PROTECTED] Cc: Sundial List sundial@rrz.uni-koeln.de Sent: Sunday, March 28, 2004 8:57 PM Subject: Re: PowerPoint Setup Hello Alexi and everybody else who kindly wrote back: Apparently, there are many people who have had this problem with Powerpoint and who would also like to be able to read their notes on their computer screens while seeing only the slides on the projector screen. All of you, except for Alexi said that it could not be done easily. I was encouraged when you told me the solution to my problem Alexi, but I just tried it (right clicking on slide while in Slide Mode and clicking on Speaker Notes), but it did not work. The notes still appear on the projection screen. So, frustrated, I went to the Microsoft PowerPoint FAQ webpage and this is what they say. There is a solution but it sounds horribly complicated and above level of expertise and not worth the effort and expense, so I guess I'll just print out 65 pages of paper prints, one for each slide. Uggh! Here's what The Microsoft FAQ says: How can I display slides on a PC connected to a projector but still view my notes (and control the slide show)? Paul Iordanides has kindly given us permission to post his essay on the subject. To do this in PowerPoint, your system must support dual monitors. Windows 98, Windows Me and Windows 2000 and Windows Xp all support Dual monitors. Win 98 supports a max of 9, and I have personally set up 8 monitors in Windows 2000 and Xp Since there seems to be a lot of confusion about dual monitors, let me define what dual monitors means: Dual Monitors, Dual Displays, Multi-Monitor -- all of these terms refer to HARDWARE configurations. For HARDWARE dual monitor support, your computer must be equipped with two or more video boards OR it must have a single multi-port video board. If you have a laptop, you must either have a chipset that supports Dual monitors or you must use an external PCMCIA video board. Some laptop brands that have models with the dual monitor chipset are IBM, Toshiba, Dell. I'm sure there are others. One of the most popular dual monitor chipsets is the ATI Rage mobility, but again, there are others. Most laptops have an external 15 pin video connector, but this does not indicate that you have dual monitor support. Simply put: Check your manual or the company support website to see if your laptop supports Dual Monitors. On my website I recommend the Appian traveler video board that you can use for dual monitor support with laptops. Multi-Show Software available at iosysoft.com allows up to 3 simultaneous shows at once if you have a four port Video board. The AppianX boards are really nice. Paul Iordanides http://www.iosysoft.com PPCwin: A Dual Display PowerPoint Controller Note: your SOFTWARE must also support dual monitors. PowerPoint 2000 and up allows you to choose which HARDWARE monitor you want to display the slide show on (and which to display your notes, etc. on) You need to set this up each time you run the show, because PowerPoint doesn't save the information. There's a hotfix available from Microsoft that will help with this. John L. Carmichael Jr. 925 E. Foothills Dr. Tucson Arizona, 85718 USA Tel: 520-696-1709 Email: [EMAIL PROTECTED] Sundial Sculptures Website: http://www.sundialsculptures.com Stained Glass Sundials Website: http://advanceassociates.com/Sundials/Stained_Glass - Original Message - From: Alexei Pace To: John Carmichael Sent: Sunday, March 28, 2004 8:36 AM Subject: Re: PowerPoint Setup Hi John Whilst in Slide Show mode, right click on the slide and click Speaker Notes. That way they should be visible to you only. Regards Alexei Malta At 16:28 28/03/2004, you wrote: Hello PowerPoint Experts: Please excuse me for asking a non-dialing question but I'm having a problem setting up my PowerPoint slide show for Oxford. My presentation is finished and I was testing it last night using a digital projector. On Powerpoint, using Normal view, there is a box on the computer screen that allowed me to write notes about each slide. The idea is that you can refer to you notes on the computer screen while you are talking about the slide. I don't want the audience to see my notes, I just want them to see the slide. But here's the problem. I've tried a lot of different settings, but no matter how I set it up, the projected image always looks the same as the computer screen. When I put PowerPoint in Slide Show mode, my notes disappear from the computer screen and just the slide is visible on both screens. In
Re: Does anyone recognise the term spider sundial ?
Douglas, You may see a 'spider sundial' in Karl Schwarzinger's pages: http://members.aon.at/sundials/bild44_e.htm Regards, Frans Maes - Original Message - From: Douglas Hunt [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Thursday, March 11, 2004 11:02 AM Subject: Does anyone recognise the term spider sundial ? Does the phrase spider sundial mean anything to persons on this Mailing- List, possibly having connections with the University of Mainz (Germany) ? Our distributor in Turkey has asked us to obtain additional information on this unusual sundial - but cannot give me further details or a photograph, although it may be some kind of 'vertical' dial with 'protruding gnomons'. With thanks in advance for any help, (or maybe a website URL if possible). Douglas Hunt. -- MODERN SUNCLOCKS - 'Human Sundials', using YOUR OWN SHADOW to tell time. Looking for a useful, decorative, yet UNIQUE feature ? - you've found it ! For further details and photographs, see our Website at: www.sunclocks.com Mail Address: 1 Love Street, Kilwinning, Ayrshire, Scotland, KA13 7LQ, UK. Tel Fax (UK): 01294 552250. International Tel Fax: + 44 1294 552250. E-mails to: [EMAIL PROTECTED] OR [EMAIL PROTECTED] - -
Re: the oldest horizontalvertical dial
Hi Marcin all, I'm looking for any information about the first use (or the first records) of horizontal and vertical sundial ? Where it was, when etc. I read about sundial history and I found quite a lot information about the oldest, most simple dials (gnomons, obelisks etc) but I can't learn about, as I mentioned, first use of horizontal and vertical dial. Do you mean horizontal and vertical POLE-STYLE dials? I recently wrote an article about the origin of the pole-style dial in the West for Zonnetijdingen (the bulletin of the Flemish Sundial Society, Nov. 2003) and the Bulletin of the Dutch Sundial Society (Jan. 2004). The most important source of information are the books by Ernst Zinner. Unfortunately, his own interpretation of his sources varies between books, so it is not easy to draw clear-cut conclusions. My tentative conclusion was that the pole-style dial was introduced in Western Europe shortly after 1400. According to Zinner, the oldest surviving pole-style dial is a diptych dial from 1417. Pole-style dials were in use in the Arab world much earlier than 1400. It has been suggested that the principle was taken back home by crusaders. Karlheinz Schaldach (Bulletin of the British Sundial Society, 1996 nr. 3, p. 32-38) argued that this was not the case, and that the appearance of the pole-style in the Western world was an independent development. Regards, Frans Maes 53.1N 6.5E -
Sundial near Adelaide
Cher François, In case you might be driving from Adelaide to Melbourne or back, you should not miss the most beautiful sundial in Australia. It is situated in Torquay (Victoria) at the Great Ocean Road, directly at the beach. This large work of art consists of a total 120.000 glass tiles. It represents a number of traditional dreaming stories of the Wathaurong Aboriginal people, including Mindii, the ever watchful Snake and Bunjil, the Eagle, Creator and Overseer. Design: Claire Gittings Glen Romanis (mosaic), Ian Sells (gnomonics). For pictures, see the Dutch version of my webpage: http://www.biol.rug.nl/maes/zonnewijzers/nl/torquay.htm Bon voyage! Frans W. Maes 53.1N 6.5E -
Mosaic Dials #5 and #6
Hi John all, The English translation of the page on the Torquay dial will come 'soon'. Your first two questions were answered in my posting already. And I'll ask my colleague Anne de Ruiter who visited the dial for additional info. Much closer by (for me, that is) is a glass mosaic analemmatic dial in Ronse in Belgium, although I did not yet visit that one either. Just go to www.biol.rug.nl/maes/sundials/ , choose Analemmatic, scroll down to Belgium and click the Ronse thumbnail. I think most of the info you would like to have is in the page. I have not been able to find a website from/about the artist Pjeroo Robjee, who designed the dial. Regards, Frans 53.1N 6.5E - Original Message - From: John Carmichael [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Wednesday, February 11, 2004 2:45 PM Subject: Mosaic Sundials Hello Frans and others, In response to your notice about the Australian Dial, I was so surprised and pleased to find out about this wonderful glass mosaic sundial! We've included a section on glass and ceramic mosaic sundials on the SGS website and have only found 4 examples in the whole world. This makes five. If any of you know of any other mosaic dials, please let me know. I definitely want to post photos and information on this dial, but I need somebody to translate that Dutch website or somebody who can fill in the following information (see list below). Also, if any of you have better high resolution photos, that'd be great. By the way, I've learned a lot about making mosaics and it is even easier than making stained glass windows. I encourage more dialists to use this beautiful medium more. You don't need expensive tools or lots of experience to make a mosaic sundial. If you go to the bottom of the Technical Information Page on the SGS website, you will find a description of the two basic mosaic techniques (the poured concrete and the grout methods). Here's the Info I need for the Australian Mosaic Dial: Sundial Designer: ? Glass Artisan(s): ? Date Constructed: ? Size: ? Adornment: ? Mottos: ? Condition: ? Comments: ? Website and/or email of designer and/or glass artisan: ? Thanks anybody for more information or photos of this or any other mosaic sundials. John John L. Carmichael Jr. 925 E. Foothills Dr. Tucson Arizona, USA Tel: 520-696-1709 Email: [EMAIL PROTECTED] Sundial Sculptures Website: http://www.sundialsculptures.com Stained Glass Sundials Website: http://advanceassociates.com/Sundials/Stained_Glass - Original Message - From: Frans W. Maes [EMAIL PROTECTED] To: Sundial List sundial@rrz.uni-koeln.de Sent: Wednesday, February 11, 2004 5:30 AM Subject: Sundial near Adelaide Cher François, In case you might be driving from Adelaide to Melbourne or back, you should not miss the most beautiful sundial in Australia. It is situated in Torquay (Victoria) at the Great Ocean Road, directly at the beach. This large work of art consists of a total 120.000 glass tiles. It represents a number of traditional dreaming stories of the Wathaurong Aboriginal people, including Mindii, the ever watchful Snake and Bunjil, the Eagle, Creator and Overseer. Design: Claire Gittings Glen Romanis (mosaic), Ian Sells (gnomonics). For pictures, see the Dutch version of my webpage: http://www.biol.rug.nl/maes/zonnewijzers/nl/torquay.htm Bon voyage! Frans W. Maes 53.1N 6.5E - - -
Re: Salvador Dal� and Sundials
Hi Richard all, There is a picture of a Dali dial (:-) in the site of Andreas Hänel from Osnabrück (in German): http://www.physik.uni-osnabrueck.de/~ahaenel/sonnuhr/ Scroll to Spanien/Katalonien - Cadaques. It is dated 1966. Judging from the hour line pattern, the dial is east-declining by 60° or so. The pole-style possibly suffered from some 'restoration'. The site does not give additional information. Note the disclaimer that some attributions may be incorrect. Cadaqués is a village on the east coast of Spain, close to the French border and close to Dali's native town Figueras. Regards, Frans Maes 53.1N 6.5E - Original Message - From: Richard Langley [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Monday, February 02, 2004 3:08 PM Subject: Salvador Dalí and Sundials While on a recent holiday in southern Florida, my wife and I visited the Salvador Dalí Museum in St. Petersburg http://www.salvadordalimuseum.org/. Currently running is the exhibition Dalí Centennial: An American Collection which celebrates the 100th anniversary of the birth of Dalí. One of the paintings on display is Noon (Barracks Port Lligat) which Dalí painted in 1954 http://dali.karelia.ru/html/works/1954_07.htm. The painting shows a vertical sundial on the wall of the barracks. Can any of our Spanish colleagues tell us if the building and the sundial still exist? Of course, Dalí was no stranger to sundials as witnessed by his famous sundial at 27, rue Saint-Jacques, Paris 5ème arrondissement http://www2.iap.fr/saf/csmp/arr5n/centrea51.html constructed in 1968. The image on the sundial bears a bit of a resemblance to his 1966 painting Self Portrait Sundial http://www.elainefineart.com/dali/self_portrait_sundial.htm Are there any other Dalí sundials -- real or painted? -- Richard Langley P.S. Fredericton is home to Dalí's huge Satiago El Grande. It is on permanent display in the city's Beaverbrook Art Gallery http://www.beaverbrookartgallery.org/, one of 4 Dalí paitings it owns. The gallery was a gift to New Brusnwick from its native son Lord Beaverbrook (Sir Max Aitken) who served in the wartime cabinet of Winston Churchill. Lord Beaverbrook was chancellor of my university from 1947 until his death in 1964. === Richard B. LangleyE-mail: [EMAIL PROTECTED] Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === - -
Re: A 'gnomon-less' sundial for locations near the Equator ?
Hi Douglas all, It doesn't obey the initial conditions, but maybe a play-object is allowed in a playground. How about a horizontal bar, on which children may turn somersaults etc.? It can double as a sundial: let the bar just tilt 2 deg (3 cm at 1.70 m length), North end upward. Hour lines are almost parallel, as this is almost a polar dial. Regards, Frans Maes - Original Message - From: Douglas Hunt [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: 18 January, 2004 7:54 PM Subject: A 'gnomon-less' sundial for locations near the Equator ? Can any of our Mailing-List experts suggest some horizontal sundial design suitable for locations almost on the Equator, (actually 2 Degrees North) ? We have been contacted by a school in Singapore, who would like to install a large playground sundial - BUT ideally having nothing above ground-level to cause any 'accidents', or increase the cost/complexity of their layout. They want to avoid a 'gnomon' obstructing vehicles in the playground area. They had initially thought of using a traditional analemmatic, but those are not really suited to locations within the 'tropics' (because the Hour- markers will interfere with the central Date-scale). We recommended using a 'door-frame polar' design, as being the most popular for schools near to the Equator (i.e., two upright supports with a near-horizontal North/South cross-piece, the shadow of which tells time on Hour-lines painted on their playground) - but they prefer an entire layout on the ground, if possible. I will be very grateful for any suggestions, as to whether there is a type of sundial which could be installed at a near-Equator location - and which does not need a 'gnomon' (apart from maybe a person!), above ground-level. Douglas Hunt. -- MODERN SUNCLOCKS - 'Human Sundials', using YOUR OWN SHADOW to tell time. Looking for a useful, decorative, yet UNIQUE feature ? - you've found it ! For further details and photographs, see our Website at: www.sunclocks.com Mail Address: 1 Love Street, Kilwinning, Ayrshire, Scotland, KA13 7LQ, UK. Tel Fax (UK): 01294 552250. International Tel Fax: + 44 1294 552250. E-mails to: [EMAIL PROTECTED] OR [EMAIL PROTECTED] - -
Sundial Park in Genk
Dear sundial friends, Some two years ago I published a website in Dutch about the unique Sundial Park in Genk (Belgium), a permanent exhibition of classical and novel sundials. Finally, the English version is out. Have a look at: www.fransmaes.nl/genk/welcome-e.htm I hope you enjoy it! If you have corrections or suggestions for improvement, let me know (off list: [EMAIL PROTECTED]). Best regards, Frans Maes 53.1N 6.5E -
Analemmatics update
Hi all, Those of you interested in analemmatic dials might like to have a look at some new or updated pages. 1) A split-analemma analemmatic dial, designed by Len Berggren and Brian Albinson, at a Simon Fraser University parking lot. See: http://www.sfu.ca/mediapr/sfu_news/archives_2003/sfunews10300310.htm This is the first analemmatic sundial in Canada incorporating the Equation of Time correction. It is similar in this respect to the famous sundial in Longwood Gardens (Kennett Square, PA, USA), see: http://www.longwoodgardens.org/Sundial/Analemma.html This precision instrument certainly deserves a more prominent location and a more permanent construction! 2) The analemmatic dial in the grounds of Mount Stromlo Observatory, near Canberra (Australia). It survived the bushfires that ravaged the Observatory last January, which destroyed all telescopes and many buildings and instruments. 3) A local committee has teken pity of the unique sundial at the Observatory of Besançon (France), which was in bad condition. It is the world's third oldest analemmatic dial and the only one that shows Julian (astronomical) hours. The Committee is well underway raising funds for its restoration. Your support is also appreciated. For these pages, follow the links in the New or updated box at my sundial site: www.fransmaes.nl/sundials/ Best regards, Frans Maes 53.1N 6.5E -
Re: Dial design
Hi Richard, It seems you have reinvented Piet Hein's helical dial. See the home page of Egeskov Castle, http://www.egeskov.dk/english/sightseeing/index.htm and click nr. 25 on the map or in the list below it. John Moir showed already that the dial does not function well outside the equinoxes in BSS Bulletin 95.1. I give an explanation of this ill-behavior in my website: www.fransmaes.nl/sundials, choose Index and goto Kvaerndrup. Regards, Frans Maes 53.1N 6.5E - Original Message - From: Richard Hollands [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: 30 November, 2003 6:34 PM Subject: RE: Dial design I've just realized, thinking about it again, that the simplest realization of a 'helical' dial is a single sheet of metal given a half-twist of 180 degrees. So long as the edges are straight and the twist is distributed uniformly then the desired line o'light effect will be achieved. [Richard Hollands] Reflection on your question suggests that you're right and that the helical dial will only be accurate at the equinoxes. This is the fallacy of treating mathematical abstractions as equivalent to real-world objects. -
Re: Sun Dagger of Chaco Canyon
Art, I like your tenacity! What else would a Discussion List be for? Much too often a discussion wanes before the issue has really been resolved or at least clarified; in a party, a café as well as on this list... Keep asking questions! Frans Maes 53.1N 6.5E - Original Message - From: [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: 28 November, 2003 12:19 PM Subject: Re: Two links to Sun Dagger of Chaco Canyon Re: Stab Dial P.S. I'm sorry if my insistence, or the mode of my insistence, on a detailed explanation ruffled any feathers. -
Re: Foster-Lambert dial
Mac, Congratulations on this stylish double-styled gem! John, Your bet is easily lost, see http://members.aon.at/sundials/bild30_e.htm. I am welcoming your case of whisky at 53.1N 6.5E. Regards, Frans - Original Message - From: John Carmichael [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Saturday, November 15, 2003 6:19 PM Subject: Re: Foster-Lambert dial Wow, that's neat Mac. I never thought anybody would actually get around to building one. I bet it's the first Foster-Lambert dial ever constructed since It's got a face only a true dialist could love (or understand)! It's nice to see how you always seem to tackle those odd theoretical dial types we often see in the Compendium and make them into actual working dials. I still have on my workbench the little interactive string shadow plane dial that you gave us all at the conference in Hartford. John John L. Carmichael Jr. 925 E. Foothills Dr. Tucson Arizona, USA Tel: 520-696-1709 Email: [EMAIL PROTECTED] Sundial Sculptures Website: http://www.sundialsculptures.com Stained Glass Sundials Website: http://advanceassociates.com/Sundials/Stained_Glass - Original Message - From: Mac Oglesby [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Saturday, November 15, 2003 9:33 AM Subject: Foster-Lambert dial 15 Nov 2003 Hello friends... After six months of months of research, design, and construction (yes, I work slowly g), my Foster-Lambert sundial saw the Sun for the first time on 9 Nov 2003. The central white disk holding the hour points measures 24 inches in diameter. I've posted a montage of four small pictures at http://www.sover.net/~oglesby/Foster-Lambert/ I you click on the filename F-L photos 9Nov03.jpg (not on the icon), it should open for you. Please let me know (off list) if you have difficulty viewing the file. I'm planning to submit an article about this dial to The Compendium, giving details of the design and construction, along with a better photo. Best wishes, Mac Oglesby - - -
Canonical hours
Hi all, Two years ago there was a discussion on this list about various types of hours, from which I cite the following fragments, about canonical (ecclesiastical) hours. Fer de Vries described the canonical hour as: Draw half a circle on a south facing vertical plane and devide the circle in 12 ( or 8 or 6 ) [equal] parts and then you have a dial with the canonical hours. A rod perpendicular to the wall is used to produce the shadow line to read the dial. Mario Arnaldi added: I would like to improve the definition of the canonical hour. Fer described quickly the shape of an usual so called mass-dial, but not all the mass-dial are always showing canonical hours, I mean canonical hours are only seven moments of the ancient lenght of the day (from sunrise to sunset), they were prime, terce, sext, nones, vespers and compline. Only these moments are canonical hours, but we use to consider them grouped by three hours a time. Because this kind of sundial were used by the Church we use to call them canonical sundials Hence, in a canonical sundial with 12 divisions, some but not all hours are canonical hours. My question then is: is there a general name for the hours shown on a canonical dial? Regards, Frans Maes 53.1N, 6.5E -
Re: New Sundial books?
- Original Message - From: Claude Hartman [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Wednesday, October 15, 2003 8:41 PM Subject: Re: New Sundial books? Is there a collection of those CLOCKS magazine articles? Hi Claude and all, The Sundials on the Internet site http://www.sundials.co.uk/home3.htm has a number of articles by Ta'Bois: - Adjusting for Longitude - The Analemma - Calculating hour lines - Disc dials - Equinoctial dials - Gnomon or style - Greenwich meridian - Hours and hours - Latitude sundials - Meantime dials - Minor adjustments - The Noon Mark - Pillar dials - Ring dials - Significant dials - Sun time clock time Regards, Frans Maes 53.1N, 6.5E -
Re: New Sundial books?
Hi Claude, Why choosing technology of the previous century? Why not moving one more step ahead and taking the spreadsheet approach? The ease of making the necessary serial calculations in one move, and graphing them right away, are quite an advancement as compared to the pocket calculator. And it might be the start for a really NEW sundial book... Regards, Frans W. Maes 53.1N, 6.5E - Original Message - From: Claude Hartman [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Monday, October 13, 2003 6:56 PM Subject: New Sundial books? Hi dialists! Does anyone know of a book written for beginning dialists that uses hand calculators? The most widely available books here in the U.S. seems to be those of Waugh and of the Mayalls. To use a calculator with Waugh requires translating all the logarithm formulas. Mayall puts all the formulas in the back of the book. Both books make such an extensive use of plotting diagrams that the calculation seems a secondary method. The excellent book by Rene Rohr also makes use of mathematical calculation as a secondary technique. I am looking for recommendations for the beginner for my Back to Basics column in the NASS Compendium. Claude Hartman -
Mars sundials
Hi all, Astrobiology Magazine has an interview with Bill Nye 'the Sundial Guy', on the sundials that are on their way to Mars right now: http://www.astrobio.net/news/article625.html Regards, Frans -
Re: vertical pole
Hi Vince, How about a 'spider sundial' ? See an example at Karl Schwarzinger's website: http://members.aon.at/sundials/bild44_e.htm Regards, Frans Maes - Original Message - From: vince and darcy winskunas [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Monday, September 01, 2003 3:10 PM Subject: vertical pole Dear list members, I have a vertical pole in an open area of my back yard. Is it possible to layout a sundial with its shadow? Is there a program to do this or would it have to be done by marking points over a years time? Also what would the lines look like--the classic analemma or something else? Thanks for the help, Vince -
Re: vertical wall dial latitudes?
Dear Bill, Have a look at their website: www.dasypodius.com and read who Dasypodius was ;-) Regards, Frans Maes 53.1N, 6.5E www.fransmaes.nl/sundials/ - Original Message - From: William S. Maddux [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Thursday, July 17, 2003 5:47 PM Subject: Re: vertical wall dial latitudes? Alain MORY Greetings Alain (and other Dasypodians ?). As a biologist and a dialist, I am intrigued by the choice of Dasypodius as name of your association. I take the Greek root dasy as meaning thick or hairy, and pod, as foot. The Dasypodidae are known to me as members of the (mostly tropical) American Armadillo Family. I can only imagine that there is some, possibly self-deprecating, or humorous, Gallic (or perhaps Alsatian?) wordplay involved. I would be most grateful if you would take a moment to satisfy an old man's curiosity as to the origins of your group's appellation. [Please forgive my deplorable lack of the capacity to have composed this note in French.] Sciagraphically, William Maddux [EMAIL PROTECTED] On Wed, 16 Jul 2003 23:03:13 CEST [EMAIL PROTECTED] writes: Hi John, hi all, latitude restrictions on vertical wall dials 1 A 1B : OK, according to me, but in the 6h-18h gap 2 : I don't think so, these sundials should receive the sun's light between spring and autumn 3 : idem, but between autumn and spring. 4 : What do you exactly mean ? 5 : I think that a vertical dial at the poles will work like an horizontal at the aequator, isn't it ? Thank you for this little sunny brainstorming ! Now I will consult my sundial softwares, to be sure of what I'm meaning... Sunny days and clear skies to all ! Alain MORY www.dasypodius.com - -
Re: New Website
Hi John all, I think your site looks very nice now - and functional! Do any of you have any format preference (GIF or JPEG) for websites? Should we change the graphics to JPEGs? Also, do you think the popups are user- friendly? My rule-of-thumb is: - use JPG for photos, i.e. all pictures with gradual changes in hue and brightness, - use GIF for schematic drawings, i.e. consisting of areas of constant hue/brightness. The reason is that this gives the smallest files. When in doubt, you can easily test for yourself: save a picture in both formats and pick the smallest result. Regards, Frans -
Analemmatic sundial in Rasht (Iran)
Hi Peter all, Following your posting last November, I have contacted Mohammad Bagheri. With his information and pictures, and the stimulating help of Reinhold Kriegler from Bremen, I have added a page about this new dial to my site. Actually two pages, as the pictures on the construction and inauguration are on a second page, linked from the first one. You may have a look at www.fransmaes.nl/sundials/, and take the Index to Rasht, or go to the Analemmatic page and scroll all the way down for the Rasht thumbnail. I wish to express my admiration for the group of people who, despite severe political uncertainties including war and threat of war in neighboring countries, have the courage and sense of responsibility to put so much effort into the study and dissemination of these universal cultural treasures of mankind. Best regards, Frans Maes 53.1N, 6.5E - Original Message - From: peter ransom [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Sunday, November 03, 2002 10:56 AM Subject: A new sundial group Mohammad Bagheri, one of my contacts in the history and pedagogy of mathematics sent me the following details about a new sundial group in Iran. I also have a picture of the analemmatic dial. If you want me to send a jpeg of it, please contact me off-list. Best wishes to all Peter Ransom -
Re: Analemmatic sundial in Torre�n, Mexico
Hi all, Martha had difficulties getting this reply throught to the list and asked me to relay the following: - - - - - - - - - - - - - - - - - - - - - - - - - - - Dave, Many thanks for your nice comments. My friend José C. Montes and I, we both follow the great topics you deal on the list, and we have learn a lot from you! At first... sorry for my English The terminator line was a great idea from José, and we decided to enlarge the Mexican Republic to the whole globe an put a small point to indicate Torreón (the place where we live) and locate the terminator line just there. The globes are 6 plane (not convex) circular stones made in green dark granite worked with sandblast. The night half is represented with neat granite and the sunlight rough with sandblast. At first we thought about convex globes, but it was highly expensive on granite. As the analemmatic ellipse is very pronounced here in Torreón (lat 25° 32'N), there is no enough place to insert the globes on the correspondent hour site, but we placed the Solstices globes in a imaginary second ellipse bigger than the hour ellipse. It means, the shadow at sunrise or sunset in the Solstices will be cast on the respective globe. (Also each globe has carved the sunset and sunrise hour). Frans Maes has been following all the sundial construction and he kindly solved our doubts and contributed with a web page for this sundial!! Thanks again Frans.. Martha A. Villegas 25° 32' N 103° 27' W Torreón, Coah. México - Original Message - From: Dave Bell [EMAIL PROTECTED] To: Sundial List sundial@rrz.uni-koeln.de Sent: Monday, February 10, 2003 5:31 PM Subject: Re: Analemmatic sundial in Torreón, Mexico On Mon, 10 Feb 2003, Frans W. Maes wrote: An enthousiastic group, headed by Martha Villegas, has established a beautiful analemmatic sundial in Torreón, Mexico, probably the first one in the country. Read all about it at: http://www.biol.rug.nl/maes/torreon/welcome-e.htm Wow! A beautiful dial, indeed, and a very nice set of pages describing it. A special addition here are the terminator maps, depicting the twilight line across the Mexican Republic at local sunrise and sunset on three dates. The maps are quite interesting in themselves. Obviously, there was a talented tile artist involved in the project! Are the maps shaded, to illustrate the terminator (and contrast in the time digits), or are they convex surfaces that actually *display* the terminator? I'm thinking here of the globe-in-miniature (Terella?) dials... Regards, Frans Maes 53.1N, 6.5E Dave 37.28N 121.97W - -
Re: Analemmatic sundial in Torre�n, Mexico
Hi all, Martha had difficulties getting this reply throught to the list and asked me to relay the following: - - - - - - - - - - - - - - - - - - - - - - - - - - - Thank you John, I am glad you have seen the analemmatic web. Since I began in gnomonics, I thought the better sundial for a place where many people do not pay attention to a sundial, it would be an analemmatic, because it is specially attractive because the human participation required to its functioning. Some time ago it was a discussion on this list about analemmatic sundial next to the tropic as a problem because the shadow length, and I was a little worried about. I wrote Frans Maes and he helped us to determine the better major axis of the dial for this latitude and people height average. We did a small model and we saw the problem is only in certain dates and certain hours and even this, we decided to build it, considering the sundial will work O.K. almost all the year. I went to the sundial the Jun 22 at noon and... guess what... yes, I practically did not have a shadow (an interesting event too), but being at 41° C, I was lonely on the park!! I noticed that the date divisions are at ten day intervals so that the correction numbers don't look crowded. If one week divisions were used, the dateline might get pretty busy. Looks great the way it is. This has resulted very practical because it is easy to get an average between two values, but in retrospective it would be also necessary to include the date where the correction numbers are, because even if we mention this on the instruction panel, people who try to understand the sundial by themselves, they have problems to identify which date is. I do not know about any analemmatic on the tropics, at least, not in American Continent. Greetings to all, Martha Torreón, Coah., México 25°32' N 103° 27' W - Original Message - From: John Carmichael [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Cc: [EMAIL PROTECTED] Sent: Tuesday, February 11, 2003 3:44 AM Subject: Re: Analemmatic sundial in Torreón, Mexico Hi Frans and Martha: That's a fine sundial and a great webpage. I also like the terminator maps, but I particularly like the time correction feature on the date line. This built-in table of correction values solves in a simple neat way the problem of showing the Daylight Savings Time correction (or legal time in Mexico) as well as the correction for The Equation of Time, without the use of a confusing analemma on the date line. I noticed that the date divisions are at ten day intervals so that the correction numbers don't look crowded. If one week divisions were used, the dateline might get pretty busy. Looks great the way it is. I also noticed that this dial is located very close to the Tropic of Cancer, making the dateline almost reach the time line. So this dial is about as close to the Equator as you can make an analemmatic and still have it work ok. There are also problems with analemmatic gnomons being too short in the tropics (Does anybody even know of any analemmatics located in the tropics? I doubt there are any.) John p.s. Is it correct to say that an analemmatic face collapses into a polar dial at the equator? John L. Carmichael Jr. Sundial Sculptures 925 E. Foothills Dr. Tucson Arizona 85718 USA Tel: 520-696-1709 Email: [EMAIL PROTECTED] Website: http://www.sundialsculptures.com - Original Message - From: Frans W. Maes [EMAIL PROTECTED] To: Sundial List sundial@rrz.uni-koeln.de Cc: Villegas, Martha [EMAIL PROTECTED] Sent: Monday, February 10, 2003 7:12 AM Subject: Analemmatic sundial in Torreón, Mexico Hi all, An enthousiastic group, headed by Martha Villegas, has established a beautiful analemmatic sundial in Torreón, Mexico, probably the first one in the country. Read all about it at: http://www.biol.rug.nl/maes/torreon/welcome-e.htm A special addition here are the terminator maps, depicting the twilight line across the Mexican Republic at local sunrise and sunset on three dates. Regards, Frans Maes 53.1N, 6.5E - - -
Re: Analemmatic sundial in Torre�n, Mexico
Hi John and all, Thanks for your appreciation! I noticed that the date divisions are at ten day intervals so that the correction numbers don't look crowded. If one week divisions were used, the dateline might get pretty busy. For the same reason some 10-day markers are omitted towards the end points of the date scale. (Does anybody even know of any analemmatics located in the tropics? I doubt there are any.) I don't know of any either; the Torreón dial is by far the closest to the equator in my website collection. But I would love to hear. p.s. Is it correct to say that an analemmatic face collapses into a polar dial at the equator? I don't think so. The ellipse would be squeezed into a straight E-W line of finite length, with the 6 am pm hour points at the tips, whereas in the polar dial the 6 am pm hour lines would, as usual, be infinitely far out. More generally speaking: the analemmatic dial would still be an azimut dial, whereas the polar dial would become an altitude dial here. Regards, Frans 53.1N, 6.5E -
Analemmatic sundial in Torre�n, Mexico
Hi all, An enthousiastic group, headed by Martha Villegas, has established a beautiful analemmatic sundial in Torreón, Mexico, probably the first one in the country. Read all about it at: http://www.biol.rug.nl/maes/torreon/welcome-e.htm A special addition here are the terminator maps, depicting the twilight line across the Mexican Republic at local sunrise and sunset on three dates. Regards, Frans Maes 53.1N, 6.5E -
Re: Sundial web pages and controlled vocabulary
Hi Richard, I don't understand your point. According to the W3C specification, the META element should be in the HEAD section of an HTML document. See: http://www.w3.org/TR/REC-html40/struct/global.html#h-7.1 In section 7.4.4. it says: A common use for META is to specify keywords that a search engine may use to improve the quality of search results. Regards, Frans 53.1N, 6.5E - Original Message - From: Richard Mallett [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, January 14, 2003 11:00 PM Subject: Re: Sundial web pages and controlled vocabulary Make sure that those keywords are near the beginning of the text on the web page itself, not just in META tags in the HTML, as the latter are considered 'bad form' by the search engines. Richard. -
Re: 3-D gnomon for Polar Dial
Hi Mac and all, I am afraid I don't quite understand the question. John would not like analemma shaped hour lines, you wrote. How might figure-8 shaped hour lines be used here?? One can simply incorporate the EoT into the hour lines of a common polar dial as a function of date, running from January to December. No figures-8, just somewhat wavy lines. And a date scale, of course. If one would manage to make a wavy gnomon, one gets a wavy shadow falling on straight hour lines. Not much of a difference, I would say. And one would also need a date scale to read the time. So what is the question actually? Regards, Frans 53.1N. 6.5E - Original Message - From: Mac Oglesby [EMAIL PROTECTED] To: Sundial Mail List sundial@rrz.uni-koeln.de Cc: John Close [EMAIL PROTECTED] Sent: Monday, December 09, 2002 3:21 PM Subject: 3-D gnomon for Polar Dial Hello All, John Close has posted this message on the NASS Message Board: Does anyone have any ideas for a Polar Dial which allows for an Equation of Time adjustment. I would not like analemma shaped hour lines as I think this would detract from the simplicity and minimalistic quality of a Polar Dial. I am told an analemma shaped gnomon for a polar dial would be hideously complicated and probably not work . Any ideas anyone? John Close John has discussed this problem with several members of this list, including me, Bill Gottesman, John Davis, and Pete Swanstrom. Some of us think that a 3-D gnomon could be designed for use with straight hour lines to correct for EoT, and some are skeptical. Please share your comments and suggestions. Best wishes, Mac Oglesby P.S. Since I do not know if John Close is a member of this List, please cc to him. - -
Re: Digital sundial
Hi Bill all, I agree absolutely with you that the digital dial is an essential addition to the art and science of dialing. Also fiber optics or other means of transforming the usual shadow edge on the dial face into whatever display form, add essentially to this. In my view, however, the most promising development has not yet been mentioned, neither in the BBS article nor on this list: the shadow plane or hour plane sundial. Strictly speaking, it is not a novel invention of the 20th century. The French mathematician Alexandre Pingré designed one in 1764 for the column of De Médicis at the Bourse du Commerce in Paris. (See the article by Denis Savoie in the NASS Compendium vol. 6(1), 1999). However, this principle was forgotten, to be rediscoverd only in the 20th century by Adolf Peitz in 1979 (see fig. 280 in Sonnenuhren, vol. 3 by Schumacher Peitz, 1981). From there, it was picked up by Marinus Hagen (see Bulletin of the Dutch Sundial Society 1985 nr. 2). Wider dissemination was given, among others, by the articles of Maddux, Oglesby De Vries (see http://home.iae.nl/users/ferdv/shadow.htm). The idea of liberating the individual hourly shadow planes from their common pole-style and rearranging them in whatever way will certainly lead to a wealth of new, intriguing and pleasing designs, once its full potential is being realized by dial designers and artists. Two other 20th century developments that contributed clearly to the AS of dialing are noteworthy, I think: 1. The upsurge of interest in sundials. After dials 'went to sleep' in the first half of the century, interest started to grow thereafter, as reflected by the founding of Sundial Societies in Germany (1971), France (1972), The Netherlands (1978), Great Britain (1989) and many others. 2. The shift from graphical methods of dial design and lay-out to arithmetical methods, like log and trig tables (by Waugh, 1973, for instance), slide rules, pocket calculators up to spreadsheet programs. Regards, Frans W. Maes 53.1 N, 6.5 E - Original Message - From: [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Sunday, October 20, 2002 2:48 AM Subject: Re: Digital sundial In a message dated 10/19/2002 4:05:59 PM Eastern Daylight Time, [EMAIL PROTECTED] writes: She dosn't however consider that the digital sundial should be recorded as an entirely new design. It is a read-out of the conventional vertical sundial and just a convenient addition to help in the ease and accuracy of reading a dial face of an ordinary sundial, she sais Please note that she does not say this in her article. She does not mention digital dials at all, so perhaps this is from a private communication between Mr. Leenders and Ms Stanier. But I do agree that a digital dial deserves recognotion as a new form of dial. First of all, it is not a vertical dial--The only places on earth that this design functions in a vertical position is at either pole. Secondly, it is radically different from any prior sundial design. I heard Robert Kellog speak about this design at the NASS convention in 2001, and it is clear that this design is the product of highly original thinking, applied with great care and effort to modern day materials, and bears little mathematical and no mechanical relationship to traditional dials. The only thing that a digital dial has in common with a hoizontal or vertical dial is that they all measure right ascention--Hardly a disqualifying factor for a distinct type of dial. Bill Gottesman - -
