Dear friends, a new issue of the Italian magazine Orologi Solari is available for download from the usual site http://www.orologisolari.eu/.
Here is the list of articles together with a short abstract: 1. - "The conical astrolabe" by Riccardo Anselmi The author, referring to the cylindrical astrolabe designed by Alberto and Nicolò Nicelli, proposes a conical version, obtained by radial projection. The conical astrolabe works similarly. Electronic versions of the two models will be made available on Cartesius Web. 2. - "Inversion of two classical gnomonic formulas" by Francesco Caviglia The inversion of two classic gnomonic formulas is discussed: the formula that gives the altitude of the Sun as a function of latitude, solar declination, and hour angle of the Sun, and the formula that gives the azimuth of the Sun as a function of the same parameters. 3. - "Notes on Asr curves and twilight curves – Part 2 of 3” by Dominique Collin The study focuses on the curves indicating the Asr prayer that can be indicated on Arabic sundials, both horizontal and vertical. The analysis is extended to the curves of astronomical twilight, used to announce the Ishā’ prayer. This issue presents the second of three parts of the study in which the author addresses the construction of such curves with a mathematical approach of advanced gnomonics. 4. - "Gnomonics in Treviso schools" by Giuseppe Flora and Elsa Stocco The new Gnomonists Association formed in Treviso has planned educational meetings and workshops for teachers and students in several Treviso schools, in the classroom or in a specially set-up room in the Valdobbiadene (TV) Civic Library. These meetings were intended to make known local sundials, and also to design and build simple sundial models. An analemmatic sundial was traced in the courtyards of three participating primary schools. 5. - "The solar instruments of the Church in Roncole Verdi" by Mario Gioia The parish church of Roncole Verdi (a hamlet of Busseto) witnessed the young Giuseppe Verdi's first steps. On the south façade of the church, hidden from the public road, there are the remains of two sundials. Their current state, severely deteriorated, is described and suggestions for the restoration of one of them are offered. 6. - "Calculation of spherical triangles using the orthogonal projection of the sphere" by Alessandro Gunella The author deals with the graphical calculation of spherical triangles using the orthogonal projection of the sphere. The required operations are made possible using CAD, which allows and facilitates the construction of the ellipse, a projection of the circle passing through a generic point on the sphere. Angles and arcs are measured by projecting them appropriately between the ellipse and the "Zero Meridian," the great circle identified by the polar axis and the equator. 7. - "The sundials of Don Pietro Corso from Fonzaso" by Elsa Stocco The author proposes an overview of sundials created by Don Pietro Corso da Fonzaso (BL). They exhibit characteristics that reveal Pietro Corso as having been trained at the Episcopal Seminary of Padua, under Abbot Giovanni Follador: the classic local mean time curve and the date curves related to days with a whole number of hours. 8. - "Some considerations on the Islamic prayer (ASR)" by Alessandro Gunella (Short contribution) Some historical - calendar - geographical considerations are proposed, regarding the islamique ASR prayer. Hope you will enjoy the reading, although in Italian only. Regards. Gian
--------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
