Vertical stereographic sundial
Dear All, As proven in a separate tread on "Sun elevation tool/ horizontoscope", stereographic projection is a fascinating geometric construction with great potential in gnomonics. During last year I explored the idea of vertical stereographic sundial and it resulted in a paper describing several stereographic sundial types: - vertical stereographic sundial, for walls of any declination and for any latitude, - four-sided stereographic vertical sundial, attractive for its “gnomon-less” form, - double – stereographic & polar – vertical sundial for walls of any declination, a vertical reference to Oughtred’s horizontal design, - folded pocket, double stereographic & polar – vertical sundial - inclined, proclined and polyhedral stereographic sundials The paper can be downloaded free of charge from Cursiva publishers website: http://cursiva.pl/e-ksiegarnia/vertical-stereographic-sundial-properties-construction-and-related-instruments/ or from Academia.edu website: https://www.academia.edu/88820719/Vertical_stereographic_sundial_Properties_construction_and_related_instruments Have fun with it ! Vertical stereographic sundials offer plenty of possibilities for sundial makers and I believe might be a very interesting addition to existing sundial types. As the geometric construction of vertical stereographic sundials with CAD software is time-consuming, it would be great to include it in existing sundial design software. I kindly ask sundial list members running such software, please consider it ! Regards, Maciej Lose --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Sun elevation tool
Dear John, I know this object as “Horizontoscope". http://www.horizontoscop.com/eng/index_eng.html I bought one recently after reading about it in one of Helmut Sonderegger’s articles, where he gives the math of it. https://www.herzog-forsttechnik.ch/wp-content/uploads/2022/08/Sonnenkompass_Flyer-2022.pdf It’s quite interesting how the hyperbolic surface makes the image independent of the height between the observing eye and the device. There is a german wikipedia entry. https://de.wikipedia.org/wiki/Horizontoskop Maybe someone from the sundial list can produce an english entry with the theory. It’s a nice device ! best regards Werner On 26 Oct 2022, at 02:45, John Pickard mailto:john.pick...@bigpond.com>> wrote: Good morning, Has anyone come across this dial-related device? https://picclick.co.uk/ARCHITECT-TOOL-Window-SUNLIGHT-SUN-ELEVATION-Enraf-144741549298.html Cheers, John. Dr John Pickard. --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Sun elevation tool
There is a description of the TNO "jellyfish", as it was affectionally known, in a paper by J van der Eijk, "Instrumentation for Solar Studies", in the *Proceedings of the CIE Intersessional Conference on Sunlight in Buildings*, Bouwcentrum International, Rotterdam 1967, and reprinted as Publication 241 of the Research Institute for Public Health Engineering TNO, Delft. A more accurate instrument on similar lines was Gunnar Pleijel's "Globoscope", a convex paraboloid whose mirrored surface reflected a stereographic projection of the solar orbit and its surroundings. (G Pleijel, "The Computation of Natural Radiation in Architecture and Town Planning", Bulletin 25, Statens Namnd for Byggnadsforskning, Stockholm 1954). A cheaper Globoscope, based on a vehicle hub cap, was described by Professor P F O'Brien, of the University of California, Los Angeles, in the journal *Illuminating Engineering. * I don't have the reference handy. John Lynes On Wed, 26 Oct 2022 at 01:46, John Pickard wrote: > Good morning, > > Has anyone come across this dial-related device? > > > https://picclick.co.uk/ARCHITECT-TOOL-Window-SUNLIGHT-SUN-ELEVATION-Enraf-144741549298.html > > Cheers, John. > > Dr John Pickard. > > --- > https://lists.uni-koeln.de/mailman/listinfo/sundial > > --- https://lists.uni-koeln.de/mailman/listinfo/sundial
