Re: analemmatic sundial on a slope
Donald, As already comfirmed by others, your thoughts about the (elliptical) analemmatic sundial will work. If the slope isn't to high a human still may act as the shadowcaster, otherwise a vertical rod is needed. But there is a second solution. Calculate the equivalent horizontal place for the sloped plane. You get a new latitude for that place and an offset in longitude. Calculate the usual horizontal analemmatic sundial for the place with correction for the longitude offset. Just put the dial on your sloped plane with the gnomon perpendicular to the plane. Best wishes, Fer. Fer J. de Vries De Zonnewijzerkring http://www.de-zonnewijzerkring.nl Molens http://www.collsemolen.dse.nl Eindhoven, Netherlands lat. 51:30 N long. 5:30 E - Original Message - From: Donald Christensen To: sundial@uni-koeln.de Sent: Saturday, September 08, 2012 4:12 AM Subject: analemmatic sundial on a slope Will an analemmatic sundial work on a slope? I've designed a sundial on a slope but I'm not sure if it will work. http://content.screencast.com/users/dchristensen777/folders/Default/media/0a769c4b-d61c-4f5d-b187-5b74dbc56e07/1.jpg This is a pic of an equatorial dial. I have projected the lines down to draw an analemmatic sundial for a horizontal surface. The sunlight strikes the blue gnomen on the equatorial dial. Where it hits the gnomen, I project it down (red) to draw the month line. The shadow then strikes the 1pm and I project that down as well. http://content.screencast.com/users/dchristensen777/folders/Default/media/6abf010e-8416-41a3-ba75-f69f63d0109f/2.JPG This is an analemmatic sundial designed on a horizontal surface. I have projected all hour and month points down to where they intersect on the gray slope. http://content.screencast.com/users/dchristensen777/folders/Default/media/5354cc54-f058-4854-bb3a-844a9b8fa89f/3.JPG This is the analemmatic sundial designed for a slope. I'm unsure this will work. I'm confident that I projected the lines correctly. A person that stands on the month line will be standing upright. They won't be perpendicular to the ground. Of course a gnomen that is perpendicular to the slope won't work. However I'm wondering if a vertical gnomen will work Cheers Donald 0423 102 090 This e-mail is privileged and confidential. If you are not the intended recipient please delete the message and notify the sender. Un-authorized use of this email is subject to penalty of law. So there! -- --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: analemmatic sundial on a slope
Hello Donald, At my fist look, your method is correct. Anselmo Perez Serrada made a spreadsheet to calculate inclining and deviating analemmatic sundials. There you could control your results. I do not know his web site but I have this spreadsheet. Maybe somebody of this list knows Serrada's website to download the newest version. On my website there is only software Alemma, which calculates different horizontal and inclining analemmatic sundials but not deviating Regards Helmut Sonderegger www.helson.at Am 08.09.2012 04:12, schrieb Donald Christensen: Will an analemmatic sundial work on a slope? I've designed a sundial on a slope but I'm not sure if it will work. http://content.screencast.com/users/dchristensen777/folders/Default/media/0a769c4b-d61c-4f5d-b187-5b74dbc56e07/1.jpg This is a pic of an equatorial dial. I have projected the lines down to draw an analemmatic sundial for a horizontal surface. The sunlight strikes the blue gnomen on the equatorial dial. Where it hits the gnomen, I project it down (red) to draw the month line. The shadow then strikes the 1pm and I project that down as well. http://content.screencast.com/users/dchristensen777/folders/Default/media/6abf010e-8416-41a3-ba75-f69f63d0109f/2.JPG This is an analemmatic sundial designed on a horizontal surface. I have projected all hour and month points down to where they intersect on the gray slope. http://content.screencast.com/users/dchristensen777/folders/Default/media/5354cc54-f058-4854-bb3a-844a9b8fa89f/3.JPG This is the analemmatic sundial designed for a slope. I'm unsure this will work. I'm confident that I projected the lines correctly. A person that stands on the month line will be standing upright. They won't be perpendicular to the ground. Of course a gnomen that is perpendicular to the slope won't work. However I'm wondering if a vertical gnomen will work Cheers Donald 0423 102 090 This e-mail is privileged and confidential. If you are not the intended recipient please delete the message and notify the sender. Un-authorized use of this email is subject to penalty of law. So there! --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: analemmatic sundial on a slope
On the website of Frans Maes at http://www.fransmaes.nl/zonnewijzers/welcome-e.htm (go to analemmatic - extra info) you will find a simple explanation of the derivation of an analemmatic sundial from an equatorial sundial. 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 Op 8-sep-2012, om 04:12 heeft Donald Christensen het volgende geschreven: Will an analemmatic sundial work on a slope? I've designed a sundial on a slope but I'm not sure if it will work. http://content.screencast.com/users/dchristensen777/folders/Default/media/0a769c4b-d61c-4f5d-b187-5b74dbc56e07/1.jpg This is a pic of an equatorial dial. I have projected the lines down to draw an analemmatic sundial for a horizontal surface. The sunlight strikes the blue gnomen on the equatorial dial. Where it hits the gnomen, I project it down (red) to draw the month line. The shadow then strikes the 1pm and I project that down as well. http://content.screencast.com/users/dchristensen777/folders/Default/media/6abf010e-8416-41a3-ba75-f69f63d0109f/2.JPG This is an analemmatic sundial designed on a horizontal surface. I have projected all hour and month points down to where they intersect on the gray slope. http://content.screencast.com/users/dchristensen777/folders/Default/media/5354cc54-f058-4854-bb3a-844a9b8fa89f/3.JPG This is the analemmatic sundial designed for a slope. I'm unsure this will work. I'm confident that I projected the lines correctly. A person that stands on the month line will be standing upright. They won't be perpendicular to the ground. Of course a gnomen that is perpendicular to the slope won't work. However I'm wondering if a vertical gnomen will work Cheers Donald 0423 102 090 This e-mail is privileged and confidential. If you are not the intended recipient please delete the message and notify the sender. Un-authorized use of this email is subject to penalty of law. So there! --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: analemmatic sundial on a slope
Hello Donald, My initial impression is that you have captured the essence of analemmatic sundials. They are a a projection straight down of the equatorial disc for the hour ellipse and the active portion of the polar gnomon for the zodiac line. Normally the projection is onto a horizontal plane, but it could be a sloping plane as well so your solution follows the correct logic. Regards, Roger Bailey. N 48.6, W 123.4 From: Donald Christensen Sent: Friday, September 07, 2012 7:12 PM To: sundial@uni-koeln.de Subject: analemmatic sundial on a slope Will an analemmatic sundial work on a slope? I've designed a sundial on a slope but I'm not sure if it will work. http://content.screencast.com/users/dchristensen777/folders/Default/media/0a769c4b-d61c-4f5d-b187-5b74dbc56e07/1.jpg This is a pic of an equatorial dial. I have projected the lines down to draw an analemmatic sundial for a horizontal surface. The sunlight strikes the blue gnomen on the equatorial dial. Where it hits the gnomen, I project it down (red) to draw the month line. The shadow then strikes the 1pm and I project that down as well. http://content.screencast.com/users/dchristensen777/folders/Default/media/6abf010e-8416-41a3-ba75-f69f63d0109f/2.JPG This is an analemmatic sundial designed on a horizontal surface. I have projected all hour and month points down to where they intersect on the gray slope. http://content.screencast.com/users/dchristensen777/folders/Default/media/5354cc54-f058-4854-bb3a-844a9b8fa89f/3.JPG This is the analemmatic sundial designed for a slope. I'm unsure this will work. I'm confident that I projected the lines correctly. A person that stands on the month line will be standing upright. They won't be perpendicular to the ground. Of course a gnomen that is perpendicular to the slope won't work. However I'm wondering if a vertical gnomen will work Cheers Donald 0423 102 090 This e-mail is privileged and confidential. If you are not the intended recipient please delete the message and notify the sender. Un-authorized use of this email is subject to penalty of law. So there! --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
