Re: strange longitude
But would anyone claim to measure declination to seconds of arc? Still seems a puzzle to me! Regards, John - Original Message - From: Frank King [EMAIL PROTECTED] To: fer de vries [EMAIL PROTECTED] Cc: sundial [EMAIL PROTECTED] Sent: Saturday, April 21, 2007 10:28 PM Subject: Re: strange longitude I looked with Google ... and I got a picture of the dial... It is an east declining sundial for local suntime and I think the value is the declination of the dial. That thought occurred to me too. In which case PL might be a slightly unusual use of the navigator's term Position Line? Strictly, a Position Line is the local arc of the circle centred on the sub-solar point that passes through the position you happen to be at. The plane of the dial stands on this arc when the outward normal to the plane is in the same direction as the sun. That is a good moment for measuring the declination of the dial which gives it some relevance. Maybe this is stretching the idea of a Position Line too far!! Frank King Cambridge U.K. --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
strange longitude
I have tried to look for the photos of the sundial of the Old Grammar School in Hawkshead that are in internet and I have found: 1 - http://www.visitcumbria.com/amb/hawkgrsc.htm ( la fotografia inviata da Fer de Vries) 2 - in http://www.sundialsoc.org.uk/Dotm/jul2001.htm 3 - http://www.flickr.com/photos/[EMAIL PROTECTED]/274942758/ From these images it is possible to see that the staff that sustains the stylus (supported to the wall),that coincides with the substylar line, passes across the 9h 50m hour line At the Hawkshead Latitude to have this substylar line it is necessary that the declination is around -27° and not -35°43.' If the declination of the dial were - 35° 43' the substylar hour would be 9h 14 m. Perhaps only a precise measure can solve the enigma :-) Looking at the photos we can also see that, very unusual thing, the plane of the dial is not parallel to the wall of the school, but more declining (Eastward ; at least about ten degrees) A last note. The photo n. 2 (sundial org) is accompanied by 4 verses of the poet T. Geoffrey W. Henslow : but these verses are not the same that, in the Henslow' book Ye Sundial Booke , accompany the image of the sundial of Hawkshead , that are How are you, mortal, did you say? Why, just the same as yesterday? But, questioner, let me ask you, How is the day ? and how are you ? Pag. 80 - and. 1914 - Best Gianni Ferrari --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: strange longitude
But would anyone claim to measure declination to seconds of arc? Hmmm. That's one reason why I hesitated to make the suggestion but there are three tiny points to note: 1. The meridian line in the Basilica di S. Maria degli Angeli in Rome was laid down in 1702 and that IS true north-south to within a few seconds of arc so it could be done in 1845. 2. In 1845 measuring longitude to seconds of arc probably wouldn't have been significantly easier than measuring declination to seconds of arc. 3. The quoted angle is 35 deg. 43 min. 40 sec. That could be interpreted as measuring to the nearest third of an arc-minute which doesn't sound quite so challenging. The use of Position Lines in navigation is attributed to Thomas Sumner in 1837. There must be readers of this list who know how things developed from then. It is conceivable that by 1845 the idea was well known to navigators and others. Writing PL on your sundial might be a way of showing that you were using modern ideas! OK. I'm clutching at straws! Incidentally, this quoted figure for longitude is within a few arc-minutes of being the co-latitude. Weird! Frank King Cambridge, U.K. --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Porcelain Sundials
Dear John, Thank you for your message. I was delighted to have the opportunity to meet you face to face at the BSS conference and to hear about the techniques you use... especially our discussions about the possibility of using durable fired porcelain instead of paint I shall certainly investigate this technology though my current client is keen to stick to paint! I have something else in mind for a year or two hence and may look very carefully at this technique then. I noted a number of intriguing linguistic differences in our discussions... I think we use the term `enamel' for `fired porcelain' which means something slightly different here. I also noted that when I talked about `fixing a dial' this was not a usage that you recognised!! Your CD, by the way, is full of absolutely splendid delights. Best wishes Frank --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: strange longitude
Dear Gianni, You are truly wonderful! You have, come sempre, solved the problem! We have all these people on the English list wondering about PL and we have to wait for you to interpret our English! I didn't think of the Geocentric Latitude and I certainly didn't think of the Reduced Polar Latitude but your calculations point to that conclusion. Your figure of f = 1/298.257 is used by Meeus but would not have been known in 1845. I agree that 1/280 is the value most likely used. You win the prize for solving this puzzle! Very best wishes Frank --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Porcelain Sundials
Dear Frank (cc Sundial List): I just wanted to tell you how much I enjoyed seeing you and getting a chance to talk with you at the conference, especially our discussions about the possibility of using durable fired porcelain instead of paint for the replacement of old deteriorated painted sundials. As you noticed, I am a big fan and advocate of using baked porcelain on metal or ceramics as the best media for making durable sundials in full color. Porcelain is the most durable of all media for making a sundial in full color. I really want to see more porcelain sundials being made in the future. I have had five of them made: four black and white ones on my sundial cupola (http://www.advanceassociates.com/Sundials/Stained_Glass/sundials_files/Stai ned_Glass_Sundial_316.jpg ), and one colored one for an attached vertical wall dial (The Wall Sconce Dial- cover of the last Compendium. http://www.advanceassociates.com/Sundials/Stained_Glass/sundials_files/Stain ed_Glass_Sundial_317.jpg ). We need to spread the word to dial designers and makers about the advantages of porcelain. I am sure that there are companies in the UK who make porcelain signage and wall art. In fact, while touring Suffolk after the conference, I came across these two companies. I have not talked with them, but I'm sure that they could make custom porcelain sundial faces from a pattern provided by a dialist : 1. Norton Castings of Norfolk Telephone: +44 (0)1953 860 998 http://www.nortoncastings.co.uk/ This company mostly makes fancy hand painted porcelain address plaques to attach to your home or business. They fire porcelain designs on to aluminum plates. They can be in full color and they will do custom designs and different shapes. These are high quality. 2. The Personalized Plaque Company Tel: 01692 58528 www.broadlandceramics.com http://www.broadlandceramics.com/ This company also makes fancy porcelain address plaques to attach to your home or business.But these are porcelain that is fired on to ceramic plates instead of metal plates. They are also in full color and can be custom designs and different shapes. Also- high quality product. In the United States, I have found three excellent companies. I'm sure they ship anywhere: 3. KVO Industries Tel: 707-573-6868 (talk to Steve) www.kvoindustries.com http://www.signsearch.com/cgi-bin/redir.pl?url=http://www.kvoindustries.com title=dtl_42868 This is the company who made my porcelain sundial faces for me. They use advanced photographic techniques to transfer designs to steel sheets. So they are not hand painted. Their quality and customer service is excellent. They can do full color and different shapes. I highly recommend this company 4. Winsor Fireform www.winsorfireform.com http://www.winsorfireform.com/ Also, a very good company. Also uses advanced techniques. If you go to www.ceramics.org http://www.ceramics.org/ you will find more companies. Hope this helps and that you try out porcelain for one of your dials in the future. --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Porcelain Sundials
Hi John and sundiallists everywhere,
You might be interested to know that Harriet James and I are currently making
a vitreous enamel on steel dial to replace an art-deco painted steel dial on a
private house. The original iron scrollwork gnomon will be reused. The firm
doing the enamelling are called Vitramet - they also did the set of four large
vertical towers dials I designed for Houghton Hall in Norfolk.
During the BSS Cambridge Conference we all admired the set of 6 dials on the
Gate of Honour at Gonville Caiuis College. These were enamelled in the
1960s, I think, by a firm in Birmingham who seem to have disappeared now.
Regards,
John Davis
John Carmichael [EMAIL PROTECTED] wrote:
st1\:*{behavior:url(#default#ieooui) }Dear Frank (cc
Sundial List):
I just wanted to tell you how much I enjoyed seeing you and getting a chance
to talk with you at the conference, especially our discussions about the
possibility of using durable fired porcelain instead of paint for the
replacement of old deteriorated painted sundials.
---
https://lists.uni-koeln.de/mailman/listinfo/sundial
RE: Porcelain Sundials
Hi Frank: I think the terms: fired porcelain, baked porcelain, or porcelain enamel mean the same thing. I have heard the term baked or fired enamel used in reference to porcelain. But you are right, baked enamel usually refers to oil based paints or powder coats that are baked on at low temperatures (like the paint on your car. John -Original Message- From: Frank King [mailto:[EMAIL PROTECTED] Sent: Sunday, April 22, 2007 8:57 AM To: John Carmichael Cc: 'Frank King'; 'Sundial List'; [EMAIL PROTECTED] Subject: Re: Porcelain Sundials Dear John, Thank you for your message. I was delighted to have the opportunity to meet you face to face at the BSS conference and to hear about the techniques you use... especially our discussions about the possibility of using durable fired porcelain instead of paint I shall certainly investigate this technology though my current client is keen to stick to paint! I have something else in mind for a year or two hence and may look very carefully at this technique then. I noted a number of intriguing linguistic differences in our discussions... I think we use the term `enamel' for `fired porcelain' which means something slightly different here. I also noted that when I talked about `fixing a dial' this was not a usage that you recognized!! Your CD, by the way, is full of absolutely splendid delights. Best wishes Frank --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Porcelain Sundials
Dear John, Does anybody know if the four round blue dials on the tower at Westminster Abbey in London are made of porcelain (vitreous enamel)? They are on the Tower of the Church of S. Margaret's Westminster (quite different from Westminster Abbey) and are by Christopher Daniel. You can see a little about these dials in: http://www.sundials.co.uk/~thames.htm but it doesn't say what they are made of. I am fairly sure they ARE enamel! Best wishes Frank --- https://lists.uni-koeln.de/mailman/listinfo/sundial
