RE: sundial Digest, Vol 94, Issue 18
Helmut, Valentin has created another variation of the cylindrical sundial. He converted the cylinder to a flat wall with morning hours on one side and afternoon hours on the other side. It looks like a giant capital I with a flat web top and bottom. The hour lines are etched on the vertical member. The top flat web creates a shadow along the full length of the vertical web. The sundial is adjusted to be perpendicular to the sun at the time of reading. You locate the time at the intersection of the shadow on the proper vertical date line. Valentin is such a pleasure to work with. For instance, he added variations of font size to the program so I could laser various sizes of the sundial and maintain aspect ratio. This variation of the vertical cylinder to a flat wall seems perfectly made for a laser application. I love it. Art Krenzel From: sundial-requ...@uni-koeln.de Subject: sundial Digest, Vol 94, Issue 18 To: sundial@uni-koeln.de Date: Sun, 20 Oct 2013 10:19:34 +0200 Send sundial mailing list submissions to sundial@uni-koeln.de To subscribe or unsubscribe via the World Wide Web, visit https://lists.uni-koeln.de/mailman/listinfo/sundial or, via email, send a message with subject or body 'help' to sundial-requ...@uni-koeln.de You can reach the person managing the list at sundial-ow...@uni-koeln.de When replying, please edit your Subject line so it is more specific than Re: Contents of sundial digest... Today's Topics: 1. Re: a unique sundial on a cylindrical column of opal glass (Helmut Sonderegger (Tele2)) -- Message: 1 Date: Sun, 20 Oct 2013 10:19:45 +0200 From: Helmut Sonderegger (Tele2) h.sondereg...@utanet.at To: f.w.m...@rug.nl Cc: sundial@uni-koeln.de Subject: Re: a unique sundial on a cylindrical column of opal glass Message-ID: 52639221.2070...@utanet.at Content-Type: text/plain; charset=iso-8859-1; Format=flowed Dear Frans, here a photo of such a Filterhut dial with vertical slits around the edge. This sundial was found some years ago by Manuel Pizarro Gavilan on a column in the couvent of La Baumette near Angers (France). Time is read where the shadow of such a single stick is shortest i.e. vertically down. On Valentin Hristov's website you find constructions where this edge outside the cylinder is turned inside (with concetric hole in the circle plane on the top of the cylinder): http://www.mysundial.ca/tsp/deltacad_sundial_macros_vh_cylinder2.html. And in these versions finally one can get Willy Lender's beautiful sundial. Best wishes Helmut --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: a unique sundial on a cylindrical column of opal glass
The article Un cadran solaire insolite sur colonne dans l'ancien couvent de la Baumette by Manuel Pizarro Gavilán was published in Le Gnomoniste in Dec 2010 and is available here: http://cadrans-solaires.scg.ulaval.ca/v08-08-04/quidnovi/XVII-4-p12-20.pdf This excellent article was also published in the SAF 'Cadrans Info in October 2010. Dials like these are often called top hat or filter sundials in English and filterhut in Austrian. Regards, Roger Bailey -- From: Helmut Sonderegger (Tele2) h.sondereg...@utanet.at Sent: Sunday, October 20, 2013 1:19 AM To: f.w.m...@rug.nl Cc: sundial@uni-koeln.de Subject: Re: a unique sundial on a cylindrical column of opal glass Dear Frans, here a photo of such a Filterhut dial with vertical slits around the edge. This sundial was found some years ago by Manuel Pizarro Gavilan on a column in the couvent of La Baumette near Angers (France). Time is read where the shadow of such a single stick is shortest i.e. vertically down. On Valentin Hristov's website you find constructions where this edge outside the cylinder is turned inside (with concetric hole in the circle plane on the top of the cylinder): http://www.mysundial.ca/tsp/deltacad_sundial_macros_vh_cylinder2.html. And in these versions finally one can get Willy Lender's beautiful sundial. Best wishes Helmut Am 16.10.2013 21:09, schrieb Frans W. Maes: Dear Helmut all, You are right, Willy Sullivan's sundial is not a shepherd dial. It is very similar to a so-called Filterhut dial; I am sure you know the type. For those who don't: that's understandable, as only a handful of examples exist. Attached is a picture of a specimen at the abbey of St. Martin-de-Boscherville (near Rouen in northern France). The time is read at the highest point of the ring's shadow edge. According to René Rohr, this type was described already by Athanasius Kircher in the 17th century. The accuracy is sometines increased by vertical slits around the edge, which makes it easier to find the sun's azimuth. Rohr continues to tell that the Arab scientist Abul Hassan al Marrakushi described already in 1272 a version in which only a small radial strip of the ring was present. Which exactly matches Sullivan's dial! Best regards, Frans Maes --- https://lists.uni-koeln.de/mailman/listinfo/sundial - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4158 / Virus Database: 3614/6765 - Release Date: 10/19/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4158 / Virus Database: 3614/6765 - Release Date: 10/19/13 --- https://lists.uni-koeln.de/mailman/listinfo/sundial
