Re: Are there any commercially-available 'Teaching Sundials', for schools ?
Hello Martina, Setting aside the matter of Educational Authorities who cannot think (!), I also agree that you might like to give this another go in order to allow the Authority to think again. There is another type of dial you might try on them – one that can also be painted on the ground and where the person standing on it casts the shadow in a similar way to an analemmatic dial. This is the human nodus horizontal dial where the dial is a conventional (though large) horizontal dial and the person stands on the noon line at a point on a scale of heights such that the top of their head is at the same height as a real gnomon would be. These are strangely rare (at least in the UK) with only a few known. John Moir’s one at Poplar in London is a recent example and it’s hard to see how any thinking person could object to something like this for children. Not only that but its operation is much easier to explain and to compare with conventional horizontal dials and also of course, given the solar time it can be used to determine the child’s height – something which they find fun. If you are interested there is an image of John’s really excellent dial in Aberfeldy Millennium Green, Poplar, London E14 at this URL: http://www.ppowers.com/poplar.htm Patrick -Original Message- From: Martina Addiscott To: sundial Sent: Fri, Apr 22, 2011 8:33 am Subject: Are there any commercially-available 'Teaching Sundials', for schools ? 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 --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Where are the women?
Well, just doing a simple count of those who title themselves Mrs, Miss and Ms (That is to say ignoring those ladies who title themselves Dr and Prof, Rev and any non-Engish titles etc) in the BSS Members list of a few months ago we have 46. That’s about 10% of the membership. Patrick --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: A blunder on the astronomical clock in Prague
Surely there must be someone from Prague on this excellent sundial mail list who might be able to make representations to those responsible for the clock? It would be nice to see it working as it should do... Failing that can someone tell us to whom we should all write? Patrick -Original Message- From: Willy Leenders To: Sundial sundiallist Sent: Sat, Feb 26, 2011 3:42 pm Subject: A blunder on the astronomical clock in Prague There is an interesting difference in the construction of a sundial and an astronomical clock. On a sundial, you can change the solar time indication to a time zone indication. This is not my preference. But you can do it. If the sundial also has lines for unequal hours or Italian or Babylonian hour lines, they should not be changed. That is different on an astronomical clock. This produced an annoying blunder on the famous astronomical clock in Prague. To please the tourists who assemble there, the clock indicates now Central European Time rather than solar time as it once was, The indication of unequal hours and Bohemian (Italian) hours now gains about a quarter in February and loses a quarter in the period of end October and begin November. On this once so accurately crafted clock ! The tourists don't worry about it. Most of them are only interested in the puppet show of the apostles in the hourly opened shutters. See more on the Prague clock on my website at http://www.wijzerweb.be/prague.html Willy Leenders Hasselt in Flanders (Belgium) Visit my website about the sundials in the province of Limburg (Flanders) with a section 'worth knowing about sundials' (mostly in Dutch): http://www.wijzerweb.be --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: part 2 of longitude correction
Hi John, I agree that in your circumstances it's eminently sensible to include the longitude correction and then have only what is a universal correction to make - that for EoT. That has to be more understandable and of course any dial designed that way is then always within (about) a quarter of an hour of being correct with respect to clock time. However where (as in the UK) the longitude correction is small the 'more understandable' solution is probably to combine the longitude correction into the overall correction graph. It is after all still (more or less) within a quarter hour of local clock time. Mind you China has to be a special case!! Regards Patrick -Original Message- From: John Carmichael To: sundial Sent: Sun, Feb 13, 2011 12:29 pm Subject: RE: part 2 of longitude correction My friend, Jim Tallman and Ihave had many discussions about longitude corrected dials. I know thatmany of the Western European dialists don’t like longitude correcteddials- especially the British dialists. I can see why they feel thisway. Their three biggest arguments against longitude corrected dials arethese: 1) They aren’t traditional, 2) They aren’t symmetrical, 3) They are so close to their Prime Meridian that the longitude correction is quitesmall and almost insignificant. But there are equally goodarguments for longitude corrected dials! In The United States, and manyother places, the sundial may be located far away from the Prime Meridian atthe edge of a Time Zone. In a perfect World, a Time Zone would only span 15degrees. But most of our Time Zones have wiggly irregular boundries thatsometimes span distances far greater than 15 degrees. Russia is anextreme example of this! There are parts of Russia that are missing entirezones! Then there’s China. The entire country only has oneTime Zone! See: http://www.travel.com.hk/region/timezone.htm For places like these, a well-builttraditional Solar Time sundial will give a time reading that can be more thanan hour off of Watch Time (Standard Mean Time). A casual non-dialistwould say that these sundials don’t work, especially if there is noEquation of Time graph available with built-in longitude correction! Correctinga dial for longitude solves this problem. For this reason, I thinklongitude corrected dials are more user-friendly. This is why Jim and I routinelymake our dials with longitude correction. That’s my two centsworth. John Carmichael From: Jack Aubert[mailto:jaub...@cpcug.org] Sent: Sunday, February 13, 2011 9:14 AM To: 'John Carmichael'; 'Donald Christensen'; sundial@uni-koeln.de Subject: RE: part 2 of longitude correction This has all been very instructive. I am not a completebeginner, but have to confess that I was under the impression that rotating thedial plate with respect to the fixed gnomon was sufficient. Somebody oncetold me I could do this and I never really thought about it. If youactually think about the longitude correction, it does become obvious that justrotating the dial plate is not going to be right. For any dials I have made, I either used one of the programslike Shadows Pro or Orologi Solari to include a longitude correction, ormore frequently, now, I use a delta cad macro and keep uncorrected solar time. I agree with Willy Leenders that sundials should tell solar time. I have a watch that can tell me mean time, but it has ceded to mycelphone which is even better. Thanks for the question and thanks for the good answers. Ikeep learning things here, many of which I should already know but somehowmissed. Jack From: sundial-boun...@uni-koeln.de[mailto:sundial-boun...@uni-koeln.de] On Behalf Of John Carmichael Sent: Wednesday, February 09, 2011 6:46 PM To: 'Donald Christensen'; sundial@uni-koeln.de Subject: RE: part 2 of longitude correction (I hit the wrong button in my last email and it went out withoutmy letter- sorry!) Hi Donald: I understand your question, because I had this same questionyears ago when I was a beginner. The answer is no. To re-phrase your question sothat everybody understands it, you are asking this- When drawing a sundialface, should you simply rotate the normal solar time hour lines about theircenter of origin by 3 degrees to obtain a longitude corrected face? No, you can not dothis. Each hour line has to be calculated and drawn individually. This is a common error some beginning dialists make when designing longitudecorrected dials. I almost made this mistake too once! To help you out (since apicture is worth a thousand words) I drew your sundial in five minutes usingShadows Pro and sent it you off list the drawing. I just didn’twant you to make a common mistake. But verify it for yourself anddon’t take my word for it. That’s how you learn! Keep asking good questions! Thanks John From: sundial-boun...@uni-koeln.de[mailto:sundial-boun...@uni-koeln.de] On
Google's Art Project and dialling
After only recently learning of the Google Art Project, I looked at Holbein's Ambassadors today and like many others I was amazed at the resolution. This huge painting, it's not far off 7ft square, is here in London at the National Gallery and it is now available to view under Google's Art Project at: http://www.googleartproject.com/museums/nationalgallery/the-ambassadors Painted in 1533 it has the most interesting collection of contemporary dialling equipment all of which are painted in immense detail. There are two globes (one terrestrial and one celestial), a quadrant, a torquetum, a polyhedral dial and a shepherd's dial and some others I don't know, all of which are set in such a way as to tell some 'story' to the understanding viewer. Until now it has been almost impossible for a sundial-interested visitor to the gallery to attempt to understand much of the detail - there just isn't time - but now with this view you can. You can even see for yourself the four place names marked on the terrestrial globe (one of which helped to identify one of the depicted persons as Jean de Dinteville, the Seigneur of Polisy) and you can even read the music and words in the open book and guess at the date and time shown on the shepherd's dial.. It doesn't (I think) help with viewing the anamorphic skull as a skull - or at least you still have to turn your monitor round to do so! - and I STILL don't understand the object behind the shepherd's dial... Anybody know what that might be? Patrick --- https://lists.uni-koeln.de/mailman/listinfo/sundial
British Sundial Society Annual Conference 2011 – Wybo ston Lakes, 29th April – 1st May 2011
Hello British Sundial Society Annual Conference 2011 – Wyboston Lakes, 29th April – 1st May 2011 Now that the New Year has arrived it seems appropriate to mention the forthcoming 2011 British Sundial Conference which will be held at the end of April. This year we shall be meeting on the border of Cambridgeshire and Bedfordshire in Wyboston Lakes which is near the quaint market town of St Neots. We shall be staying at the very well appointed Robinson Executive Centre there. The centre is very easy to get to by road, train or air and because this is a conference venue, all activities are being held in the same building. The Conference will consist of oral presentations about sundials and related issues, a display by attending delegates of interesting dial related items that they have brought to the meeting and a Saturday afternoon coach tour of some interesting dials in the area. Good food, a bar and good company are assured! The 2011 Andrew Somerville Lecture: "Ne quid pereat: researching and collecting sundials in the age of precision timekeeping" will be delivered by Dr Rebekah Higgitt, Curator for the History of Science and Technology at the National Maritime Museum, London. We already have offers for a full programme of lectures. Why not join us for an interesting and enjoyable weekend? You do not have to be a Member of the Society to attend. Further information about all the arrangements for this meeting, some pictures of the venue and a downloadable booking form can all be found at our special Wyboston Lakes Conference page. There is a link to it from the home page of the society's web site (http://sundialsoc.org.uk) or it may be accessed directly at any time by using the short-form direct link: http://bit.ly/wyboston I do hope we may be able to welcome members of this sundial mail list to the meeting. If you should have any queries do please get in touch with me off list at conferen...@sundialsoc.org.uk Regards Patrick Powers BSS 2011 Conference Organiser --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: stop the earth
Hi, Others have explained the problems regarding seeing/identifying/using geostationary satellites to determine longitude but if you are prepared to consider alternatives, there is one that simply uses radio and a clock. Construct a device to work out local noon, like a north–south line. Time the difference between local noon, measured from the sun, and the 12 o’clock noon-GMT 'pips' broadcast on the radio from the BBC World Service. This has been a project within the UK's Open University Rough Science programme for some time, see http://www.open2.net/sciencetechnologynature/maths/measuring_latitude_and_longitude.html The question is has anyone tried it? The above site suggests that even using a pendulum to measure the time difference it can be accurate to one degree. Regards Patrick -Original Message- From: Brent To: Sundial List Sent: Thu, Dec 9, 2010 3:17 pm Subject: stop the earth I have been wondering why I can determine my latitude using simple tools but not my longitude? The earth is a sphere, I would think if you can determine one you can determine both. The problem with calculating longitude seems to be the earth is rotating on its' axis. If the earth stopped spinning, the sun would not rise and set but stay put, and then I could determine the angle of the sun from my horizon and thus determine my longitude. Well that's not going to happen anytime soon. But if I could see a geostationary satellite I could essentially do the same thing don't you think? I have seen orbiting satellites at dusk many times but does anyone know if you can see geostationary satellites with the naked eye? thanks; --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Declination and Inclination
Well, it's "Dec then Inc" for me - though I only have limited experience with inclined dial design. Hmmm, I hadn't ever really rationalised it as you have. An excellent topic. Thanks Frank -Original Message- From: Frank King To: sundial Sent: Tue, Aug 31, 2010 3:37 am Subject: Declination and Inclination Dear All, An intriguing question has been raised on the Italian Sundial list by Fabio Savian. Slightly re-expressed he is asking... When specifying the orientation of a plane dial, is your order: A) Declination then Inclination B) Inclination then Declination ? This is important because rotations are not commutative: R1.R2 does not equal R2.R1. My own answer is firmly (A) and (slightly simplified and avoiding using either word) I think as follows: 1. Start with a vertical plane facing due north (sic). 2. Rotate about a vertical axis until it has the correct azimuth. 3. Rotate about a horizontal axis until the tilt is right. I use this order because both rotations are about axes IN THE PLANE being used. This keeps rotation matrices simple and so on. An alternative is: 1. Start with a vertical plane facing due north. 2. Rotate about a horizontal axis until the tilt is right. 3. Rotate about a vertical axis until the azimuth is right. This is fine but the second rotation is not about an axis in the plane being used. Here I quote a delightful observation by John Davis in the BSS Glossary referring to a definition of inclination: Beware: this convention is not followed by all authors. He could be referring to a host of other definitions :-) OK. Which way do you all do things: Dec then Inc or Inc then Dec ? There is no right answer but it would be interesting to hear who does what! Frank King Cambridge, U.K. --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Sundials and Google Maps
Hi Brad, I would be very interested to have a copy please. The incorporation of maps into dials is something that has interested me ever since I saw Harvard curator William Andrewes's map dial at Burghley House near Stamford in Britain. He called his a Longitude Dial. It's based on an idea proposed in 1607 by Franz Ritter of Nuremburg who devised a world map projected from Nuremburg, with its lines of longitude arrayed to serve also as hour lines. I think Andrewes makes these to special order so there very few of this sort of dial around! There's more about his dial at http://www.longitudedial.com/index.html. Your dial sounds equally, if not more intriguing. Patrick -Original Message- From: Brad Lufkin To: Sundial Mailing List Sent: Tue, Aug 10, 2010 12:22 am Subject: Sundials and Google Maps I've incorporated Google Maps into an Oughtred dial. As you know, the Oughtred dial can be drawn on any azimuthal map projection (Oughtred himself chose the Stereographic). Since the dial is drawn on a map, it's possible to drawn Earth features such as countries as part of the dial. What I've done (and I'm pretty sure this is new) is incorporate the ability to download and use Google Maps in the dial. The technique works with geographic dials as well. I tried to send an example to the SML but the image is 90KB+ so will not pass the size filter. I'd be happy to send the diagram to whomever is interested. Brad --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: sundial atlas
Thanks Roger for that very clear summary of the problem of dial theft that we see so often in the UK. There are plenty of dials in the public domain in the UK and elsewhere that are not vulnerable and it is to Fabio's credit that these can now be identified to a wider audience via the Sundial Atlas. Indeed the Sundial Atlas could be a very valuable tool in understanding some of the enigmas of dialling like the use and prevalence of mass dials in Europe. However the position with some dials is quite different and theft, even from Heritage sites where security is strong, is a serious problem. The BSS's Registrar John Foad maintains a list of dials that are known or strongly believed to have been, stolen. It currently extends to no fewer than 15 pages. The BSS Register of dials includes both mention and details of many of these valuable and vulnerable dials only because dial owners have been assured that the Society will not publish the existence of their dial to any other than to its membership and to the Heritage Organisations. In this way the full corpus of knowledge of UK and Irish dialling is maintained and even extended. If rare and valuable dials, particularly those in private or church ownership, are to be publicised on the internet then their owners will not be able to insure them and as a result owners will increasingly prevent anyone, even genuine researchers, from viewing their dials. Not only that but where a theft can be linked back to inclusion in an Internet Atlas a case will arise in law for compensation. This is a huge problem in the UK and I hope that Fabio will include some much needed advice on the pages of the Sundial Atlas site to those who may be thinking of recording any dial that is vulnerable to theft or vandalism. Additionally I would hope that the entries in the Sundial Atlas can be monitored regularly to remove or modify entries that fall clearly into that category. Otherwise the Sundial Atlas faces being seen as a thieves' catalogue and none of us would want that. Regards Patrick Powers -Original Message- From: Roger Bailey To: Fabio ; sundial Sent: Mon, Aug 9, 2010 12:58 am Subject: Re: Re sundial atlas There are significant cultural difference in these notes on the sundial atlas. In Italy, feral cats eat pasta, but not the cats in the UK. The cultures are different in many ways. In Italy and most of continental Europe, the dominant sundial type is the vertical declining dial on a building. In the UK the brass/bronze sundial in a garden or churchyard dominates. Many historic sundials have been stolen in the UK to sell to collectors in America or scrap dealers for their copper content. Few dials on the continent are at risk in the same way. We need to recognize the specific risks giving the precise location of any valuable sundial. I have enjoyed viewing an old bronze horizontal sundial in a churchyard in the English Lakes district dedicated to Wordsworth. I hope it is still there as it is at risk. I have also enjoyed viewing the equatorial ring and astronomical quadrant on Santa Marie Novella in Florence, placed by Egnatio Danti in 1574, to determine the exact value of the obliquity. Both are important in many ways but the English dial is more at risk. Neither are yet in the sundial atlas. I agree with the concerns expressed by John. When marking a dial on the sundial atlas or elsewhere, consider first is the dial worth noting and second, what are the risks of showing its precise location. Regards, Roger Bailey >From North America where we have very few heritage sundials at risk . -- From: "Fabio" Sent: Saturday, August 07, 2010 3:54 PM To: Subject: Re sundial atlas > Dear John > > It looks like a call not to use Sundial Atlas rather than to appreciate > its popular development useful to everyone. > I would remind that: > > - in SA you can indicate a sundial on the map in the square of the nearest > city, and not exactly where it is, indicating the rightness of the > position as 50m, 500m, 5km (about 3 miles) or more then 5km, and without > revealing the exact location, but still allowing to obtain info on the > sundial. > > - the publication of the photo of a sundial is the best burglar alarm, > since it is assumed that a sundial can work only when exposed to the Sun, > where everyone could recognize it if its picture is known. > I would not recognize a stolen sundial even I saw it because I don't know > the photos of the stolen sundials. > (on SA a sundial may be classified as 'stolen') > > - it is not possible to know who will read the catalogs with censuses of > the sundials which are periodically published, therefore is not internet > to be dangerous. You should also advise not to publish catalogs or books > on sundials. > > - on the web there are now thousands of photo of sundials posted on social > networks by photographers or simply cu
Re: Do the Police really object, to interactive 'Human Sundial' features?
Dear Linda,
The UK police have no jurisdiction over such problems. It is your client who
needs assurance. I have designed several public dials - including analemmatic
dials of the same principle as those supplied by Sunclocks - without any
problem. To suggest that there is really a serious danger from such things is
(in my mind) ludicrous. Britain has recently endured over ten years of a
government that sadly seems to have promoted the idea that if anyone has a
problem then it must always be someone else's fault, that the more obsessive
aspects of Health and Safety protection practice must be followed and above all
has promoted the lunacies of political correctness - much of which is actually
neither political nor correct. Thankfully, and of course aided by a financial
cut back in all sectors, these issues are getting addressed as we speak.
Having said this there are some sensible aspects to be mentioned. Unless you
have professional indemnity insurance of your own I think you should ensure
that you notify your client that you are not insured against your own
professional mistakes but will quote for making a model beforehand that may be
tested and the final design, based on that model, accepted before proceeding to
commit to the final construction. For analemmatic dials you simply need to
adhere to the principles of paving flatness that Councils themselves adhere to.
What other uses the locals put the dials to is nothing to do with you. A large
horizontal dial that I designed for a small town centre in Northumberland was
of 12m diameter with a long tubular gnomon. At about 5am on the morning after
the official opening a lager lout was spotted at the top of the gnomon by the
local police. Undoubtedly this sort of thing happens and you should ensure
that the strength of the components of any such dial can handle this type of
misuse. But the Client's (here the Council's) Public Liability Insurance will
cover any resulting mishap.
Regards
Patrick
-Original Message-
From: Linda Reid
To: sundial
Sent: Mon, Jul 12, 2010 3:38 pm
Subject: Do the Police really object, to interactive 'Human Sundial' features?
Dear Members of this 'Mailing List',
I am a mosaic artist, based in the United Kingdom - and am currently
working with a local Community Arts organisation on a project, plus
one part of which is to be a proposed "Sunclock" ('Human' Sundial).
We were intending to obtain a customized set of layout plans, from
"Modern Sunclocks" (in Scotland) - but it seems that they require a
'disclaimer' letter from us, acknowledging that we fully understand
all the implications of creating this feature in a public location.
They directed us to a page on their website, which details what can
happen - that specific page is: www.sunclocks.com/pics/fs-015.htm
Those 'negative' aspects are outlined at the top of that page, and
they also said that Planning Permission might not be approved - due
to objections raised by local residents, plus 'Police' authorities.
I then had a brief discussion with a local Police Community Liaison
Officer, who said that he fully appreciates why "Modern Sunclocks"
were just being honest with us - plus that some interactive public
features would be likely to attract 'undesirable' people, who "take
it over" as theirs (so discouraging people who we want to use it).
Is this really true, that what we think should be a very colourful,
functional and interactive 'Human' Sundial - will eventually become
a feature which actually the local population do NOT want to have?
"Modern Sunclocks" were very helpful - and said that they could sell
three times as many sets of plans, if only they did not have to warn
customers about the 'implications' (based on many years experience).
Do the members of this 'List' have any comments (good or bad), about
installing such interactive sundials - since we do not want to go to
the time and expense of creating this, if local people do not really
want it. Most people said they would be happy, (although we did not
mention any of those negative factors, when conducting short "market
research" - because we were totally unaware of them, at that time).
I shall very much look forward to receiving feedback, on the above.
Sincerely,
Linda Reid.
--
---
https://lists.uni-koeln.de/mailman/listinfo/sundial
---
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Re: DST Misconceptions
LOL. I do like that Frank. I always thought that the advantages of DST increased a tad as one went North. Indeed I understand from friends there that in Scotland the advantages are such that even the farmers manage to forget the fact that their animals have a short problem when DST came in and out. The advantages for other aspects of DST life begin to be realised there. Not least the way in which children can go to and return from school in more daylight than before. This has (of course) led to the suggestion that the Scots should have their own time. But there are some advantages of DST for those of us in the higher latitudes. The other thing that hasn't yet been touched upon in this mail list exchange is the idea of DST being adopted permanently instead of the 'normal' time. This strange idea is often suggested by those living in Kent and was even tried in Britain some time ago yet later abandoned for good reason. The idea has also recently been tried in Portugal; once again with a massive vote against after a period of trial. Yet the insanity persists. Has this odd suggestion been tried outside Western Europe I wonder? Regards Patrick -Original Message- From: Frank King To: kool...@dickkoolish.com Cc: sundial@uni-koeln.de Sent: Mon, Mar 15, 2010 2:59 pm Subject: Re: DST Misconceptions Dear Dick, > In Boston, the summer solstice sunrise > is at 5:08 AM. That's two hours before > I'm even thinking about getting up. :-) OK. Suppose I broke into your apartment while you were asleep and advanced all your clocks so they said 7:08AM. Would you think about getting up then? That's pretty much what Governments do except that they don't have to break into your house. They make a law so that you change your own clocks :-) Suppose they introduced another law that said... During the summer months you should cut the first foot off all tape measures so they start at 1 instead of 0. We would all be a foot taller during the summer. Everyone would be happy. I think I shall set up a political party to introduce this legislation! Why stop there? During the summer we could add 10 volts to the readings of all voltmeters and 10mph to all speedometers. We could finally pass the Indiana bill that attempted to set the value of pi to 3.2, but only during the summer of course. Oh, how about adding $1bn to all bank accounts too? Hey, wait a minute. Didn't they already try that one? Enjoy your extra daylight! Frank King Cambridge, U.K. --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Cyrus the Great and sundials
Hi David, You do provoke the most amazing interest! What sort of clients do you have for your dials? Well, Cyrus the Great (allegedly 576 BC – December 530 BC) might have known (or known of!) Anaximander (610 BC–c. 546 BC) who (I think!) was the one who introduced the sundial to Greece, it having been previously used in Mesopotamia, Egypt and China. Reading fluently from Wikipedia (!) I see that : The Suda relates that Anaximander explained some basic notions of geometry. It also mentions his interest in the measurement of time and associates him with the introduction in Greece of the gnomon. In Lacedaemon, Anaximanda participated in the construction, or at least in the adjustment, of sundials to indicate solstices and equinoxes.[40] Indeed, a gnomon required adjustments from a place to another because of the difference in latitude. In his time, the gnomon was simply a vertical pillar or rod mounted on a horizontal plane. The position of its shadow on the plane indicated the time of day. As it moves through its apparent course, the sun draws a curve with the tip of the projected shadow, which is shortest at noon, when pointing due south. The variation in the tip’s position at noon indicates the solar time and the seasons; the shadow is longest on the winter solstice and shortest on the summer solstice. However, the invention of the gnomon itself cannot be attributed to Anaximander because its use, as well as the division of days into twelve parts, came from the Babylonians. It is they, according to Herodotus' Histories (II, 109), who gave the Greeks the art of time measurement. It is likely that he was not the first to determine the solstices, because no calculation is necessary. On the other hand, equinoxes do not correspond to the middle point between the positions during solstices, as the Babylonians thought. As the Suda seems to suggest, it is very likely that with his knowledge of geometry, he became the first Greek to accurately determine the equinoxes. Does that give you any hopes? Long shots just don't come into this!! Regards Patrick (PS This just has to be another excellent topic for the bar at Exeter!) -Original Message- From: David M Brown To: sundial Sent: Wed, Mar 10, 2010 1:52 pm Subject: Cyrus the Great and sundials Here's a challenge for all you gnomonical cogniscenti Is there any way in which Cyrus the Great (yes, I had to look him up, too) can be linked to sundials. I suspect not, but maybe one or two of you know better. I kid you not - this is a genuine query that has been put to me. I don't have the answer. Do any of you? David Brown Somerton, Somerset, UK --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Would this dial work?
For those having difficulty accessing the URL a better one for this would be: http://www.freepatentsonline.com/2637108.pdf Regards Patrick -Original Message- From: Peter Mayer To: 'sundial list' Sent: Tue, Mar 2, 2010 2:05 pm Subject: Would this dial work? Hi,A while ago I came across US Patent 2637108 for a sundial watch byViesturs(http://www.freepatentsonline.com/2637108). The patent charminglysuggests that it may be used 'for play and sport, where a good mechanical watchis endangered by pressure, sand and water, and therefore not always adapted tobe carried around. As play and sport are mostly exercised during sunny weather,a portable sundial can well replace a mechanical watch on these occasions".As may be seen from the copy of the illustration which I've attached, itappears to be an equal-angle dial. It has a compass (label b)to allow N-Salignment of the dial. The shadow is cast by two vertical threads (label f). After some pondering, I have concluded that the sundial may be a form ofmagnetic azimuth dial, but this could well be wrong.My question is: would this dial work?best wishes,Peter --Peter MayerPolitics DepartmentThe University of Adelaide, AUSTRALIA 5005Ph: +61 8 8303 5606Fax : +61 8 8303 3443e-mail: peter.ma...@adelaide.edu.aucricos Provider Number 00123M---This email message is intended only for the addressee(s)and contains information that may be confidential and/orcopyright. If you are not the intended recipient pleasenotify the sender by reply email and immediately deletethis email. Use, disclosure or reproduction of this emailby anyone other than the intended recipient(s) is strictlyprohibited. No representation is made that this email orany attachments are free of viruses. Virus scanning isrecommended and is the responsibility of the recipient. ---https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Globe Theatre Sundial?
Yes they are at the Globe Theatre. The dials are actually mounted on a building at the edge of the New Globe Theatre Courtyard. You will recall that there was great difficulty in finding the space to locate the Globe replica and it is therefore quite close to other buildings. The dials are nearly Direct ones and are visible from New Globe Walk. Both dials radiate from a central circular grey disc (650mm diam) edged in gold. The south dial declines west. the west dial declines north. They were designed by Johanna Migdal and made by Brookbrae Ltd. Installed I think in 1998. Hope this helps. Patrick -Original Message- From: John Carmichael To: sund...@rrz.uni-koeln.de Sent: Fri, Jan 29, 2010 12:43 pm Subject: Globe Theatre Sundial? Hello British Dialists in particular: I came across these two photos of a double sundial attachedto a tower. The photographer claims that it is located at the GlobeTheatre in London. But this tower certainly doesn’t look like the GlobeTheatre! Do any of you recognize these photos an know where thesedials are located? And do you know anything about them? Thanks so much, John http://www.flickr.com/photos/41099...@n00/3624421695/ http://www.flickr.com/photos/41099...@n00/3625238356/in/set-72157619640732933/ ---https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
BSS Conference, Exeter,UK, 9-11 April 2010
This is a reminder to all who might wish to attend the British Sundial Society's 2010 Annual Conference. This year's conference will be our twenty-first and it is being held in the beautiful County of Devon at the University of Exeter in the West Country of the UK. It will run from the 9th to the 11th April but accommodation may also be booked for nights before or after these dates if required. The University have asked BSS to confirm total numbers by the 1st February 2010 so as to ensure availability. All bookings should therefore be made and paid for by then. Booking forms can be printed off by using a link under 'Conferences' on the Society's web site: http://www.sundialsoc.org.uk Cheques are preferred from UK attendees but overseas delegates may pay by credit card. It may still be possible to accept bookings after the above date but confirmation will have to be delayed whilst the University is contacted and will of course be subject to availability. Anyone interested to know more about the Conference, the lectures, to see the sort of accommodation at Exeter and to find out how to get there etc, can find further details on our special information page. There is a link to it from the BSS web site or it may also be accessed by going directly to: http://www.ppowers.com/exeter.htm If you should have any queries not answered by the above information page please send them to me off list either to conferen...@sundialsoc.org.uk or to patrick_pow...@dunelm.org.uk Either will reach me. Thank you - We all look forward to meeting up with you in Exeter. Regards Patrick Powers BSS Conference Organiser --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: antikythera mechanism
Frank: An amazing device indeed. Sadly I couldn't get to the one day Cambridge Symposium on it last winter but I much enjoyed viewing the video clip on the Nature web site: http://www.nature.com/nature/videoarchive/antikythera/ I was left musing just how arrogant we are today to assume that the ancients couldn't 'do' some things. What's the betting now that Stonehenge was not just a religious site but might indeed have been as Fred Hoyle believed? Patrick -Original Message- From: Frank Evans To: Sundial Sent: Fri, Dec 18, 2009 8:19 pm Subject: antikythera mechanism Greetings, fellow dialists,I first read about the Antikythera Mechanism in Time in Antiquity, a book by Robert Hannah which was reviewed in the Bulletin of the British Sundial Society Vol. 21, 2009. I now repeat Frank King's earlier signal that a very good and up-to-date account of this instrument appears in Scientific American for December. Frank got hold of a copy of this issue long before it appeared on the stands of the newsagent, W. H. Smith in the UK, where it arrived only a few days ago. This amazing instrument, brought up from the sea bed in 1900 has epicyclic gearing, a device 1500 years ahead of its time. There are gear trains for the current date, for the Metonic cycle, for the Saros cycle and for the moon's motion. Want to know the date of the next solar eclipse? Just turn the crank.Frank 55N 1W---https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
BSS website restored
Following earlier messages on this list that mentioned a strange problem with our web site, I am delighted to be able to announce that the BSS website at http://www.sundialsoc.org.uk/ is now restored. Thank you all for your patience. Regards Patrick --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Troublesome things these sundials!
Peter Tandy probably echoes the astonishment of all of us that any sane person would suggest shooting at a sundial but there is at least one other example that I know of. The otherwise excellent dial at Minster Abbey (on the Isle Sheppey in Kent, UK) is one. The poor image attached might just be small enough to get transmitted but it certainly shows the extensive damage. It must somehow be appealing in some way. I can only think that it must be the sound of the hit that attracts these yobs. Hmmm, maybe it is the fact that the said physiotherapist has himself engaged in this practice that makes him suggest it to others Patrick >Why would a (presumably sane) physiotherapist suggest firing at a sundial? Was >it a test to see if the 'gunman' could even find one! (How many are there in >the Sunderland area?). Surely there are easier targets to find than that? Do >we know if he succeeded and what damage was done?< Don't let your email address define you - Define yourself at http://www.tunome.com today! <>--- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: 2010 Convention
Hi John, I am not sure which of the many conventions there are around the world that you might want to come to but the British Sundial Society's next Annual Conference is to be held in Exeter University in the County of Devon, UK on April 9-11, 2010. More information can be found on our web site at: http://www.sundialsoc.org.uk. Click on the Conferences menu and the further links in there for details, a link to a special web page about the conference details and to print a booking form. I do hope you will be able to visit us. If you (or anyone else on this list) would like to present a paper or simply just attend the conference please do visit our web site as above for details. Just to whet your appetite, our 2010 plenary lecture (The Andrew Somerville Memorial Lecture) will be given by Dr DJ Bryden formerly curator of the Whipple Museum (University of Cambridge) and Keeper of Science and Technology at the National Museums of Scotland. He will speak on: "A Gallimaufry of Dial Makers and Designers". Regards Patrick -Original Message- From: John Mulholland To: sundial@uni-koeln.de Sent: Sun, Nov 15, 2009 10:10 pm Subject: 2010 Convention Shadow watchers, I have been tracking all of you with much joy, anticipation and education. I have made a few posts but I must kneel before such greatness. What is so truly admirable about this site is the humbleness with which information is shared. I cannot wait to meet you in person. Has the convention date and location for 2010 been established? John Mulholland NEK Vermont --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Origin of the Analemma figure?
The BSS Glossary (courtesy of John Davis) says: The word analemma has had several other meanings in the history of astronomy and dialling. In the first century BC, the Roman engineer Vitruvius used the word to refer to a graphical construction, equivalent to today's orthographic projection. In the second century AD Ptolemy used analemma to mean an instrument acting as a nomograph for defining the angles of a dial. The use of a modern analemma on a dial dates to around 1640, and the first treatment in English was by Samuel Foster in 1654. Does this help? Patrick -Original Message- From: Jack Aubert To: sundial@uni-koeln.de Sent: Sat, Nov 14, 2009 11:18 pm Subject: Origin of the Analemma figure? I recently revised my notes for a sundial talk I was giving which included a section on the EOT, and its connection with the traditional figure 8 analemma. I wanted to explain its origin, or at least be able to answer the question if asked, but have not been able to find any believable references on how it emerged. I assume that the source of the figure is simply a “connect the dots” picture of what the sun, or a gnomon pointer will trace it out over the course of the year projected onto a surface. But I do not see how the dots can be generated without using an external non-solar source of time. The Wikipedia article on the EOT has a confusing statement to the effect that Ptolomey was aware of the variation in the sun’s movement and even devoted a chapter to the subject, but then says that he did not correctly account for the two sources of variation. Is there any evidence that the Greeks or Romans ware aware of, and used, the analemma representation, perhaps generated by reference to a clepsydra, or did it first appear when mechanical clocks became prevalent? Jack --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Another Human Gnomon ... Vertical in Bruz (France)
Excellent. I have never seen a vertical version before. Thanks for that Patrick -Original Message- From: robic.joel To: sundial Sent: Mon, Nov 2, 2009 10:26 am Subject: Another Human Gnomon ... Vertical in Bruz (France) Hi John, Patrick, Willy, Fer and all, Here is the new one I began last winter: http://www.cadrans-solaires.fr/style-humain-bruz.html the vertical morning part is finished now, I will complete later by the horizontal afternoon part Best wishes Joël http://www.cadrans-solaires.fr/ --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Location aerial photography online
Hi Jim, There is also http://www.multimap.com/ It is a mapping site which also has aerial views. I am unclear as to whether the views are more up to date than Google Earth's but it might be worth a try... Regards Patrick -Original Message- From: J. Tallman To: Sundial Mailing List Sent: Fri, Oct 30, 2009 1:40 pm Subject: Location aerial photography online Hello All, Every once in a while it is good to ask a question on this list about things that can change/improve over time with the progress of technology online... Whenever I get a new sundial order I usually go online to one of the mapping services to check declination and site orientation. Normally, I go to Google Earth first and usually find what I need there. However, their imagery seems old sometimes, like it has not been updated very often (if at all) If I can't get a good result because the location is a new home in a new development, I go to bing.com and check it on their maps/aerials. They seem to have more recent aerial imagery much of the time. Sometimes it still is not good enough. Does anyone on the list have any other favorite mapping resources that I have not mentioned? There may be new ones out there that I don't know about! Best, Jim Tallman www.spectrasundial.com www.artisanindustrials.com jtall...@artisanindustrials.com --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Another Human Gnomon Horizontal?
Hi John, I have been trying to find out the real details of this dial (installed 2006) but not with much success. It is at: 37 48 08.78S, 144 57 57.19E and the square is referred to as Carlton's "Piazza Italia" since it seems two Australians went to Italy to study the art of working in this sort of stone and came back and built the square. Sadly Google Earth does not help much though it shows the layout OK. There are web sites where the dial is mentioned as properly designed - viz: “The design of the solar clock is the work of Andrea Tomaselli’s Italian Porphyry group and continues their fascination with time pieces and public space. In order to make the 45 m2 solar clock (or sundial) keep the correct time, the stonemasonry had to be exact and so GPS equipment was used to ensure the stone laying was totally precise. All this added an extra layer of complexity and challenge to the job. See http://www.infolink.com.au/n/Melbourne-s-newest-piazza-wins-an-MBA-award-n763733 Afterwards the designers gave a master class in the use of porphyry - you might have been interested in that, see http://mams.rmit.edu.au/3xdi011sak221.pdf and I see that the same group, as part of a cultural exchange undertook to draw a new mural and sundial in Trento Italy. http://www.artshub.com.au/au/news-article/views/visual-arts/a-new-mural-in-the-painted-city-of-trento-italy-68366 Sadly though all these articles concentrate on the artistic aspect and not the gnomonic one. Maybe we need to make direct contact with the designers? Regards Patrick -Original Message- From: John Carmichael To: sund...@rrz.uni-koeln.de Sent: Fri, Oct 23, 2009 7:45 pm Subject: Another Human Gnomon Horizontal? I found this photo of a beautiful large spiral-shaped sundial that looks like it might be another rare human gnomon horizontal dial. It’s located at Argyle Square in the Melbourne suburb of Carlton, Victoria, Australia. See the rectangle with little boxes in it on the meridian line? I think these little boxes are human height markers. To use the sundial, one stands on the box that corresponds to his height. But it is difficult to see what the text is inside these little boxes because the photo is not very large. http://www.flickr.com/photos/adonline/2895001478 --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Dials and clocks
Hi Brian There is a picture of the dial and a few details at http://www.ppowers.com/tompion.htm Regards Patrick -Original Message- From: Brian Albinson To: 'Sundial List' Sent: Mon, Oct 19, 2009 3:39 pm Subject: Dials and clocks Gnomonists From last Saturday's Canadian Globe and Mail: "In the Pump Room in Bath, England, there is a pendulum clock that was donated in 1707 by Thomas Tompion, a famous clockmaker. On the windowsill close by is the sundial that was supplied with the clock" Does anyone have photos of the clock and dial? Brian Albinson --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Do sundials (in public places), attract 'undesirable' people ?
Hi Keith, They do not attract any more undesirables than any other public feature. The warning is simply one to ensure that if any such does occur you cannot say you were not warned! It is true that any new feature attracts attention and interest and possibly may even be regarded by some as a challenge. There is a large conventional horizontal dial in Northumberland and the day after the formal public opening by the local MP, the police found a lad sitting atop the gnomon with a can of lager in his hand at 5am! No damage was done and the dial is still there (I think) and not damaged... I wouldn't expect that an analemmatic dial such as you intend to build should attract any more undesirables than any other part of the Diamond does already. Patrick -Original Message- From: Keith Christian To: sundial@uni-koeln.de Sent: Sun, Oct 18, 2009 11:57 am Subject: Do sundials (in public places), attract 'undesirable' people ? Our "Friends of Port Sunlight" group have proposed installing a 'Human Sundial' into a local area, as an attractive interactive feature - and we had obtained the layout plans, from "Modern Sunclocks" in Scotland. For any UK members of this group, you may know that Port Sunlight (in 'the Wirral' part of Cheshire) is a highly prestigious area, and which is also protected by all kinds of 'heritage' regulations. Our chosen location is known as "The Diamond", plus we intend to use local stone. During one of our recent meetings, it was pointed out that the "Modern Sunclocks" website says that installing this feature into a public area may attract 'undesirable' people (drug addicts, prostitutes, etc) - who would tend to use this Human Sundial as their regular 'meeting-place'. This is detailed at the top of page: www.sunclocks.com/pics/fs-015.htm There is also a link to further 'risks and dangers', of installing one. Although we would really love to have a "Sunclock", if this is going to become a meeting place for drug-dealers and alcoholics - then it would certainly not be in keeping with the 'prestigious' nature of this site. My reason for sending this message to the "Sundial Mailing List", is to ask if anyone has experience of sundials (in public places) becoming an attraction to 'undesirable' people - such as those I mentioned, above. Basically, we need to decide whether we should proceed with installing this "Sunclock" in that location - as we do not want to have a feature which might considerably 'lower the tone', of our Port Sunlight area ! Looking forward to any comments and/or advice, concerning this matter. Keith Christian. -- --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: sunset/sunrise times
Fascinating. According to this web site (for schools!) you can do it and allegedly get within 10% too, by simply doing the two measurements first when lying down and secondly when standing up! Better on the heart I suspect! http://www.darylscience.com/downloads/DblSunset.pdf Patrick -Original Message- From: Woody Sullivan To: sund...@rrz.uni-koeln.de Sent: Sun, Oct 18, 2009 11:45 am Subject: RE: sunset/sunrise times Tom & Thibaud et al.: An interesting consequence of the time of sunrise/set varying with height of the eye is that in principle one could do the following: Observe sunset over the ocean from a beach; quickly climb stairs of a tower or run up a cliff or sand dune (for Holland!), and then see a second sunset! I've always wanted to do this, but never have been able to plan it, etc. The air would also need to be stable. From Tom's formula, translated into time where we take the sun to be moving at ~45 deg to the horizon (of course this varies with latitude), a change from 0 to 3 meter gives one a sunset 21 sec later, and 0 to 10 m, a 38 sec delay (just possible running up stairs!). Note that one in principle can determine the radius of the Earth by making measurements of the time delay and one's change in height! Has anyone ever done this, or heard of someone doing it? Cheers, Woody = At 9:48 AM -0700 9/23/09, Tom Kreyche wrote: Content-Type: multipart/alternative; boundary="=_NextPart_000_0083_01CA3C32.F9B99180" Content-Language: en-us The Explanatory Supplement to the Astronomical Almanac has several separate and extensive discussions on this topic, in particular section 9.33 in the 1992 edition, page 487. A small portion of the section is: "At sunrise and sunset the apparent altitude of the upper limb on the horizon is zero and hence the adopted true altitude in degrees is h = -50/60 - .0353 * square root of H where H is the height, in meters, of the observer above the horizon." Atmospheric refraction has so many uncertainties that making such a small adjustment is meaningless for practical purposes but it's an interesting mathematical exercise. From: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] On Behalf Of Th. Taudin Chabot Sent: Wednesday, September 23, 2009 2:41 AM To: sund...@rrz.uni-koeln.de Subject: sunset/sunrise times All programs that calculate the sunrise/sunset times use an eye height of 0m. Many take the refraction in their calculations. But what is the effect of a normal eye height of 1.5 m when the observer is standing at sealevel like the beach. And when the eye height is even considerabel higher because the observationpoint is something like 300m above sealevel. Thibaud Th. Taudin Chabot, . tcha...@dds.nl --- https://lists.uni-koeln.de/mailman/listinfo/sundial -- ** Prof. Woodruff T. Sullivan, III Center for Astrobiology & Early Evolution Dept. of Astronomy Box 351580 Univ. of Washington tel. 206-543-7773 Seattle, WA 98195 USA fax 206-685-0403 --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: no analemma
Not really an answer to your question but if you accept the current half-year instead of the current month, Chris Daniel's Dolphin Dial at Greenwich (SRN 2157 - The Queen's Silver Jubilee dial) has two plates by which each half of the year may be accommodated but it is not adjustable by month.. ?Whether anyone changes the dial plates twice a year now I do not know. ?Sad if not...? Patrick -Original Message- From: Frank Evans To: Sundial Sent: Sun, Oct 4, 2009 8:42 pm Subject: no analemman Greetings fellow dialists, I'm not a great lover of displaying the equation of time on dials, except for maybe the finest. The main disadvantage, it seems to me, apart from the messiness of the addition of the analemma curve or a table of values, is the demand upon the viewer to make some understanding of what might appear rather complicated. Have there, I wonder, been dials made which simply show the required correction for the current month, e.g. "[October] For clock time apply [-14 minutes]"? Variables are in brackets and the correction is for mid-month, near enough for dials which are divided to quarter hours or worse. These are the vast majority. The correction would require monthly attention, of course, but it would be possible to insert two interconnected windows, one for the month and one for the correction, in the dial plate to accomplish this. And of course the month could be set by the observer if desired. Longitude, too, could be included, to satisfy the clever fellows who examine the dial and then knowingly consult their watches. But am I going over already trodden ground? Do such dials already exist? Frank 55N 1W --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Moment dials
I too like the description 'Moment Dial'. These don't just have to be limited to one moment either and as John suggests they don't have to be in stained glass. My favourite is the wonderful liberation monument in Guernsey, Channel Islands (SRN 3230) designed by David Le Conte and Eric Snell. It marks the 50th anniversary of Guernsey's liberation and as the shadow of the obelisk moves throughout every 9th May it marks out the timing of events during 9th May 1945. See more at: http://www.astronomy.org.gg/liberation.htm It was described in BSS Bulletin, 1996,1, p33. Patrick -Original Message- From: John Foad To: sund...@rrz.uni-koeln.de Sent: Sun, Sep 27, 2009 10:00 am Subject:=2 0Re: A stained glas projection dial? I like the name 'Moment dial'. A modern example is the 100 foot 'Peninsula Spire' in front of the Millennium Dome at Greenwich. A stone slab in the surrounding paving records "At 11:06 hrs on the 17th May each year the mast shadow is centered on this stone". Regards, John - Original Message - From: John Carmichael To: 'Th. Taudin Chabot' ; sund...@rrz.uni-koeln.de Sent: Sunday, September 27, 2009 1:57 AM Subject: RE: A stained glas projection dial? I know this isn’t like=2 0your projection dials Thibaud, but one can have a sundial without any hour or date lines at all. I call these “Moment Dials” for lack better name. (Is there an official gnomonic name for these John Davis?). These are perhaps the simplest of all dials. They are simply a nodus whose shadow, or projected beam of light, indicates a specific time on a specific date. I saw a couple of them in old churches in Italy last year where there was a hole in the wall and a beam of light shined on a religious relic inside the church at a certain time on a certain date. In this case of the odd stained glass struct ure in Venice, the entire round roof made of stained glass might cast its image centered on the circular floor at a certain date and time. So maybe it could be a “Moment Dial”. I guess you’re right that it isn’t a true projection dial like the ones you and Fred came up with. Heck- it’s probably just some sculpture that a crazed artist dreamed up! John From: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] On Behalf Of Th. Taudin Chabot Sent: Saturday, September 26, 2009 12:45 PM To: sund...@rrz.uni-k oeln.de Subject: Re: A stained glas projection dial? This is definitly no sundial, not even a projection dial. If it was the (shadow)lines should be curved. However the idea could be used to make a nice projection sundial. Thibaud At 18:54 26-9-2009, John Carmichael wrote: Content-Type: multipart/alternative; boundary="=_NextPart_000_0001_01CA3E8F.55EAD820" Content-Language: en-us Have any of you see this odd structure in the Giardini at the 2007 Venice Biennale? I’m trying to figure out how this might function as a sundial. If it is a sundial, it might be classified as a stained =2 0 glass projection dial. My best guess is that when the colored projected image of the circle is centered on the white circular surface on the ground, that this is some significant time and date. Any ideas? See: http://www.flickr.com/photos/caranti/1405841967/in/pool-1207...@n23 John p.s. Photos of unusual existing and potential gnomons have been pouring into this pool. As of this morning there are 627 entries! http://www.flickr.com/groups/1207...@n23/ John L. Carmichael Sundial Sculptures 925 E. Foothills Dr. Tucson AZ 85718-4716 USA Tel: 520-6961709 Email: jlcarmich...@comcast.net My Websites: (business) Sundial Sculptures: 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) Gnomons, Styles & Nodi: http://www.flickr.com/groups/1207...@n23/ (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 (educational) Sundial Cupolas, Towers & Chimneys: http://StainedGlassSundials.com/CupolaSundial/index.html --- https://lists.uni-koeln.de/mailman/listinfo/sundial Th. Taudin Chabot, . tcha...@dds.nl --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/s
Fwd: Solar Coordinate Calculation (well one of them!)
Hi Jim, I cannot really help you other than to say that the following are the coefficients for a 9th order polynomial which calculates in decimals of a minute the Equation of Time at Noon for each day in 2010 (not a leap year) where x is the serial number of the day ie Jan1 is 1 and Dec 31st is 365.? ?Apart from the end effects of the final two days of the year it produces results within (and often well within) 15 secs of that obtained from Smart's formula (from which it is derived courtesy of Excel's LINEST function). ?The last two days of the year are within 26 secs of the Smart figures. ? Regards Patrick _ x9 ?-5.49274E-19 x8 ?8.53571E-16 x7 ?-5.21923E-13 x6 ?1.55941E-10 x5 ?-2.24411E-08 x4 ?1.17534E-06 x3 ?1.95441E-06 x2 ?0.00441065 x ?-0.490197443 c ?-3.076415827 2009/9/21 James E. Morrison Each year, the Astronomical Almanac publishes polynomials for calculating the mean solar orbital elements (mean longitude, mean anomaly, etc.) as a polynomial with the day-of-year as the index.? The formulas are valid only for a given year. Does anyone know of a place on-line to get the polynomials for 2010? Best regards, Jim James E. Morrison janus.astrol...@verizon.net Astrolabe web site at http://astrolabes.org --- 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: gnomon protection - shadow ridge dials
Hi Chris, ?Yes when I was Registrar, I did tell them as soon as I got the photo from my daughter but never had a reply! ?Sadly so many dials in the Register suffer a similar fate. ?Even a specially commissioned dial (at Milton Keynes) was turned to make the gnomon more pleasing by being in line with buildings rather than N-S. ?The designer protested but was overruled.. ?Quite astonishing... Interesting idea regarding the Italian hours aspect for the Regent's Park 'dial', I hadn't thought of that. Regards Patrick -Original Message- From: Chris Lusby Taylor To: sund...@rrz.uni-koeln.de; patrick_pow...@compuserve.com Sent: Wed, Sep 9, 2009 8:15 pm Subject: Re: gnomon protection - shadow ridge dials Thanks for the photo Patrick. Has anyone told the zoo that the sundial has?been installed back-to-front?The globe should be turned around 180 degrees, and positioned north, not south, of the centre of the base. As it is, it's totally useless. By the way, the base could have been inscribed with radial lines that indicate Italian hours (or time until sunset). An opportunity lost, it seems. ? Chris ? --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: gnomon protection - shadow ridge dials
No-one so far (I think!) has mentioned the lovely 1989 dial at Regent's Park Zoo in London. ?A pictureof it ?taken by my daughter can be seen at http://www.ppowers.com/regentspark.htm Patrick -Original Message- From: Claude Hartman To: David Bell Cc: sundial@uni-koeln.de Sent: Mon, Sep 7, 2009 6:53 pm Subject: Re: gnomon protection - shadow ridge dials See the work of Roger Berry : http://rogerberry.info/Sculpture/SanMateo/san-mateo-shadow-04.html Here he has a field of shafts at the angle of incident sunlight. He has commented "At any moment during the day one pole casts its shadow on itself. At that time the shadows of the other poles point to the base of that pole, creating a swirling dance of shadows from morning to evening." In the realized sculpture, grass surrounding the poles partially obscure the drama. David Bell wrote: > Very nice! I was thinking of it on a flat surface, with the tubes > variously inclined, but this spherical model works great, too. Call it > a Sea Urchin dial, maybe... > > Dave > > Sent from my iPhone > > On Sep 6, 2009, at 11:36 AM, Rodney Heil wrote: > > >> I made a quick POV-ray model of my conception of an "anemone dial" or >> "porcupine dial" and it is posted at >> www.flickr.com/photos/sundialstuff. Thanks to Roger for suggesting >> flickr. >> >> Respectfully, >> >> Rod >> ~35.5 N 117.5 W >> --- >> https://lists.uni-koeln.de/mailman/listinfo/sundial >> >> > --- > 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: Living Plant Sundial. Wow!
It's a nice dial and certainly makes a fine photo but sadly it is wrongly 'delineated! The numerals (in clipped dwarf box) are arranged like a clock and the gnomon is not properly trimmed. One interesting feature though is that the gnomon is of an 'egg in cup' design formed from two varieties of yew grafted onto each other; golden yew on top and dark Irish yew below. We only have a few (?three) topiary dials in the UK are there others in other parts of the world? Patrick -Original Message- From: John Carmichael To: 'Sundial' Sent: Fri, Sep 4, 2009 4:28 pm Subject: Living Plant Sundial. Wow! =0 A Before I made sundials, I was in the plant nursery business for twenty years. So when I saw this photo, I was absolutely stunned! I can’t imagine how difficult this was to make. See this Living Plant Sundial- with a cone gnomon no less! It doesn’t get any better than this! http://www.flickr.com/photos/bradman334/3772144228/in/pool-1207...@n23 John Carmichael p.s. Thank goodness for Flickr! --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re Augusta dial
As well as that link, there's another mention with a second picture at http://pressherald.mainetoday.com/story.php?id=280061&ac=PHnws Circumferentors were out of fashion in Europe by that time I see - so this must be quite rare. ?Even though it's well protected I think it might need better protection than is being suggested. Patrick --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Is this a sundial?
As you say, it does not look like a proper dial at all. ?I suppose there might be a nodus (which we cannot see in the photo) that would enable it to show time on two dates in the year but it doesn't look like it. It looks like yet another non-dial. Sadly there are quite a few around! Patrick -Original Message- From: John Carmichael To: 'Sundial List' Sent: Sat, Jun 27, 2009 7:16 pm Subject: Is this a sundial? ? Is this a sundial?? See: http://www.flickr.com/photos/hiddensarah/487384689/?addedcomment=1#comment72157620640577688 ? If it is, it appears that it only tells the solar azimuth and not the time.? ? ? --- https://lists.uni-koeln.de/mailman/listinfo/sundial Don't let your email address define you - Define yourself at http://www.tunome.com today! --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Translations
No one else (I think!) has so far mentioned this simple tip for when you are using computer translation. ? As we know the more simply you express yourself the better chance there is of a computer translation being understandable and in order to check this it's a good idea after doing a translation to get the same software to translate it back again to your own language. ?If you can understand the double translated version then almost certainly the first translation will be understandable by a native speaker. ? Patrick Don't let your email address define you - Define yourself at http://www.tunome.com today! --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Wall declination using google earth
>Do you have any information about the accuraccy of google earth in order to measure declination?< It can be excellent but as has been mentioned, your display may not be set? correctly to make it easy to achieve good accuracy. ? We had a conversation on this list some?time ago (10 Feb 2008)about the apparent mis-alignment of large horizontal dials when viewed on Google Earth. You can overcome this effect by using the placemark pins to establish the line of interest and then computing the declination from measurements on that line rather than reying on the GE Compass. Regards Patrick Don't let your email address define you - Define yourself at http://www.tunome.com today! --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: A Sundial as a Prize
Message text written by Tony Moss >I usually recommend a white fill for just the same reasons but client preference mostly tends towards black, although not for any diallistic consideration, and the customer is always right!< Another excellent use of white infilling is the use of talcum powder on an old eroded dial in order to be able to see and indeed photograph the engraving. I first heard of this trick some time ago but had never seen it used until John Davis sent me some images of a very worn horizontal dial for the BSS Register. The result of using the talc was amazing. It certainly confirms your view. I now carry some with me in my camera bag - much to the family's amusement! [And thanks to you John for that.] Patrick
Re: HELP on Zodiacs
Message text written by Ron Anthony Subject: HELP on Zodiacs > Help, > > I'm away from my notes, and I need the degree values needed to draw the 6 lines of declination for the entry into each of the Zodiac. > > Anyone have the values handy?< Waugh (p207) gives these (in degrees and decimal mins) as averages based upon Eastern Standard time, viz: Aries 0d 0m Taurus 11d 28.5m Gemini 20d 9.3m Cancer 23d 26.6m Leo 20d 9.3m Virgo 11d 28.5m Libra 0d 0m Scorpio -11d 28.5m Sagittarius -20d 9.3m Capricornus -23d 26.6m Pisces -11d 28.5m They correspond to solar longitudes of 0, 30, 60 90, 120, 150, 180, 210, 240 270, 300 and 330 degrees and vary slightly each year. Hope this is of use. Patrick
beaded analemma date sequence
Message text written by John Carmichael >We noticed that the Shadows sundial generator program has analemmas with the following dates of each month: 1,6,11,16,21,26. Why would this sequence be better than: 1,5,10,15,20,25? Certainly the average sundial user would find it easier to read 1,5,10 etc.< If you did use the sequence 1,5,10,15 etc you would be in good company since the better 18thC English horizontal dials used this date sequence on their Equation of Time scales. Patrick
Re: head nodus
I have been asked where the UK dial designed as a gnomon-less horizontal dial was located. In truth I don't yet know. I only found out in talking recently to a UK BSS member who told me inpassing that he had designed such a dial. I expect to receive a report form for the BSS Register in due course. I hope to be able to pass on more details shortly. Patrick
[britishsundialsociety] Re: head nodus
Message text written by Thibaud Taudin-Chabot >as far as I know you can not use lines on an Analemmatic Sundial.< Yes that's right but I think that John has abandoned his idea of an analemmatic dial in favour of this suggestion of a conventional horizontal dial but one without a gnomon. Instead of a gnomon he would use a human standing at the correct spot for his height. This person's head would therefore form a nodus whose shadow would fall on hourlines drawn from the dial's origin. Not only would it make it easier to use in low latitudes it would also be easier for use by persons of significant variation in height - both problems with true analemmatic dials. I only know of one such dial in the UK but there may be more in the US. Sorry if we have confused you by our mail Patrick
Re: head nodus
Message text written by John Carmichael >Or, instead of using a person, I could place a vandal-resistant vertical post, pilar or obelisk at the dial center which could be used for sunset & sunrise date/time/ direction readings and this would also give the dial a three- dimensional aspect as suggested by Sara Schechner. This would draw attention to the dial. Also, the hour lines would radiate from this point.< You will need to form a balance between having the pole as an attention drawing device and it generating its own possibly confusing shadow. Incidentally, if you had such a pole you could place a nodus on it and that could be used for declination lines >Also, in order to be able to tell time with short shadows around noon in the summer and to accomodate short people, it will be very important to mark the hour lines as close as possible to the gnomon foot (where the people stand). Correct?< Yes it will - but that is good because the presence of hour lines helps you with very short shadows. A true analemmatic dial has no hour lines and it is this that makes it hard to read at all accurately with humans of short stature.. >By the way, what do you think of marking the places the human gnomons should stand using four sets of footprints (4ft. 5ft. 6ft. & 7ft,)? Sort of corney and not very artistic, huh?< No not at all. In fact I would encourage you to do it because in my experience people using human marker dials tend to put their toes up against the line rather than the underside of their heel (which is more likely to be directly under your head!). Footprints would therefore help eliminate that error. Of course you need to place the heel of the drawn footprint in line with where you think their head will be! All the best
RE: analemmatic program & fotos
Message text written by "Henry Hatem" >The "human" dials I have seen at the gnomon point have a "ladder" painted on the ground marked off in height so if you are 5' you stand here and 6' up one "rung" 4' down one "rung"< Excellent suggestion. I think you are referring to an interesting alternative version of the horizontal dial where the human's head effectively forms a nodus along the style of the 'non existant' gnomon. Thus taller people stand nearer the Noon mark and the shorter stand further away - the ladder scale being set so that the different heights of people form the sloping gnomon. Time is read by judgement of where the shadow of one's head falls among the hour lines. This idea may actually make it a little easier to design a workable dial for the lower latitudes. John C might like to consider it instead of a true analemmatic dial John, were you commissioned to design a 'human' dial of any appropriate design or does it have to be an 'analemmatic' one? Patrick
IIII at IV
Message text written by INTERNET:[EMAIL PROTECTED] >A question I am often asked is why do English clocks with Roman numerals have (instead of IV) at the '4' position and most Continental and American clocks appear to have the correct IV?< This is something which has been around for a very long time indeed. The first clocks with dials (c 1400s or possibly earlier) used the '' form of the numeral four and it is possible that this was a common usage at the time. However, It is thought by others that the use of '' more nearly balances the equally heavy 'VIII' on the other side of the dial and that is the most usual explanation. It does imply an emphasis on appearance which might be overstated for the earliest years of clock manufacture though that was certainly not the case in later times. So my guess is that it may have been in quite common usage originally and was carried forward because of the way in which the appearance seemed more balanced. Early clocks using the 'IV' form do exist. In the days when bracket clocks were popular nearly all were made to go for 8 days or more (some continental designs even ran for a couple of weeks). It proved difficult to design a striking mechanism that would stay powered for such a long time and Joseph Knibb (I think) developed what is called 'Roman Striking' which followed the Roman numeral system. It used two bells of different pitch. A time involving a Roman 'I' was struck on one bell and a time involving a 'V' was struck on another bell. Thus hours were struck in a sort of 'ting-tang' way. 'X' was regarded as two 'V's. To make things tie up Knibb used a 'IV' on his chapter ring instead of '' but it was recognised that it looked (and still looks!) unbalanced. Incidentally clocks by Knibb are rare enough but clocks with Roman Striking are very rare indeed. Patrick
Can anyone help?
Can anyone possibly help me regarding a dial manufacturer that signs their dials with a copyright symbol and the word 'Solstice'? The police in the UK have recovered a stolen horizontal dial and have asked me as BSS Registrar if we can identify it and its owner. It is one of a few modern ones characterised by the maker's name simply being recorded by a copyright statement following the stated design latitude; viz Latitude 51d 30m. (c) Solstice We know of a few such dials but all are either still present on their pedestals or are designed for a latitude other than the one for which this recovered one was designed. Because the dials all appear to be designed for a specific latitude it is possible that the maker might have records of their sale. Accordingly I am trying to find the name and address for the maker of these 'Solstice' dials. Can anyone please help identify the source of these dials? Many thanks Patrick
millenium bug
Message text written by Frank Evans >I can reveal that it is the second "n" in "millennium".< Someone told me that in French it is spelt with one 'n' - no doubt someone on this list will tell me if I am wrong - if not then this 'bug' doesn't travel East! I wonder if this varies in other languages too? Patrick
