Hi Gina,What a lovely magazine. Subjects all sound very intresting. But only if I could read it in English as that is all I know.Regards,Roderick Wall. Sent from my Samsung Galaxy smartphone. -------- Original message --------From: Gian Casalegno <gian.casale...@gmail.com> Date: 8/5/19 3:56 am (GMT+10:00) To: sundial <sundial@uni-koeln.de> Subject: Orologi Solari n. 18 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. "A sundial made inside a cone" by Aironi JohnWe describe a sundial drawn inside a hollow cone, with a slit and a gnomonic hole on a generatrix. Sunlight penetrating inside the cone through a slit projects on the inner surface of the cone a light strip indicating the time. The formulas for tracing hour lines and calendar lines are shown.2. "Ancient hour circles on the sphere are not maximum circles. Clavio's demonstration with AutocadLT." by Albéri Auber PaoloCristoforo Clavio, after a long discussion with his colleagues, finally offered a demonstration that the maximum circle of ancient time relative to two antisymmetric declination circles is different for each pair of chosen declination circles, that is to say that the hour lines relative to the ancient hour are not maximum circles. Here we propose a simplified demonstration with images taken from AutocadLT geometric constructions.3. "Small composite sundials" by Anselmi RiccardoThe author presents a model of a gnomonic hole dial made with an ice cream container. In particular two specimens are shown and described declining respectively to the south and to the west.4. "The millstone of time" by Baggio FrancescoThis article describes a horizontal mobile gnomon sundial already manufactured and registered in Sundial Atlas with the code IT013689. Project steps are explained and possible variants are proposed.5. "An app for dialists… aspirant clockmakers" by Casalegno GianpieroThe author describes an Android app that simulates some famous tower clocks. The main features are described trying to underline the most interesting aspects for a gnomonist.6. "Definition of the orientation of a flat wall" by Caviglia FrancescoThe definitions used by gnomonists for the parameters that specify the orientation of a flat wall (gnomonic declination and inclination or slope) are here discussed. Unambiguous and suitable operational definitions are provided and some proposals are advanced.7. "A reflection behind the other: the double-mirror" by Ferro Milone FrancescoDouble-reflection geographic sundials are realized by using double-mirrors. The project is carried out with the help of a dynamic software (Geogebra), a geographical one (GMT) and a gnomonic one (Orologi Solari by Gianpiero Casalegno). Three computing examples and a project image terminate the article.8. "And before Foster ?" by Gunella AlessandroThe author wants to remind the reader that the use of "rulers" in the construction of sundials, a method generally attributed to Samuel Foster, was actually already proposed in the previous century. In particular an instrument is shown as already described by Clavius and probably of Germanic origin.9. "The analemma and the Cathedral of Majorca" by Pol i Llompart Josep Lluís, Ruiz-Aguilera DanielThe authors describe the cathedral of Majorca and explain how they made the photos of the solar analmma above the "cathedral of light".10. "A Roman portable watch" by Quadri UlisseThe author describes the use and the principle of operation of a portable solar clock from the Roman era, kept at the Museum of the History of Science in Oxford and of which he made a copy in brass and steel.A digital bonus can also be downloaded for additional reference material.Hope you will enjoy the reading, although in Italian only.Ciao.Gian Casalegno Mail priva di virus. www.avast.com
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