Orologi Solari n. 31, agost 2023

Gràcies a la gentilesa dels nostres col·legues italians, ja ens podem descarregar de la xarxa el n. 31 de la revista Orologi Solari. Recordeu també descarregar, en el mateix enllaç, el "bonus" que conté material complementari.

Aquí teniu la llista dels articles que apareixen en aquesta revista, juntament amb un breu resum en anglès:

The level of the Meridian Line of Augustus: two phases or only one?

Paolo Albéri Auber

"...observatio XXX iam fere annis..." is the evidence presented by Plinio (79 AD): if the "observatio" were made despite the debris from the floods of Tevere river, certainly someone (in the hypothesis of the "two phases", lacking the embankment of the hypothesis "one phase") removed the debris after each flood event. From this historical evidence we can deduce some logical consequences against the "two-phase" hypothesis (Buchner, Heslin) and in favor of the "one-phase" hypothesis.

The Obelisk of Augustus and the modern Meridian Line of Piazza Montecitorio

Paolo Albéri Auber and Lucarini Cesare In 1998 the well-known gnomonist Edmondo Marianeschi created a Meridian Line in Rome in Piazza Montecitorio. In the context of the rearrangement of the whole square, it finally allowed the Obelisk of Antinori of 1792 to project its shadow on a pertinent trace. Marianeschi talked about it at the XI National Seminar and also published in Gnomonica n. 3 but left out some details that the authors intend to complete here. Marianeschi considers his meridian line as an indicator of midday and not as a seasonal marker, the purpose to which the Obelisk of Augustus was instead dedicated with its Meridian Line of 9 BC.

Creation of a sundial by laser cutting

Riccardo and Andrea William Anselmi

This article describes the creation of a sundial with the lines cut out of a steel plate using a digital controlled “laser cutting” machine. The work also led to an enrichment of the Cartesius Web software.

The Iconantidiptic Meridian of Giovanni Battista Amici and the Dipleidoscope of Edward J. Dent

Bruno Caracciolo

A new type of low cost and practical instrument for the determination of the noon was devised by E. J. Dent who started mass production. The device was based on a system of mirrors that determined the formation of two images that overlapped at the moment of the transit of the Sun at the meridian. G. B. Amici replaced the mirrors with a glass prism, maintaining the generation of two different images coinciding at the time of true noon.

Building a sundial without gnomonic knowledge

Gian Casalegno

The author intends with this smartphone app (essentially a modern implementation of the "patience" method) to allow anyone, even without any gnomonic knowledge, to build a sundial. The app can also prove useful to the expert gnomonist for the creation of a sundial on a non-flat surface that is difficult to define with a mathematical equation.

A problem that doesn't exist. Recovery of the project parameters of a sundial

Alessandro Gunella

Starting from the remains of an old vertical dial, the author graphically reconstructs the parameters adopted. First identify the sub-style line, the axis of symmetry for the sundial track, and then go back to the Equinoctial, the Horizon line and by the gnomonic triangle to Latitude and Declination.

The sundial on an inclined and declining wall graphically constructed according seventeenthcentury texts

Alessandro Gunella

The author proposes a graphic method for building sundials on inclined and declining surfaces, the result of a personal reworking of various contributions taken from seventeenth-century texts. The topic, already addressed by the author on other occasions, becomes more direct and precise here and enriched with new ideas suggested by further studies.

Rooster sundial

Alessandro Gunella

With graphic approach, the author defines the layout of the rooster sundial, an original two-wire sundial on a polar cylindrical surface, conceived by Francesco Baggio and already calculated with mathematical methods and already approached by Gian Casalegno in two articles published in Orologi Solari and The Compendium.

The UTM cartographic system

Michele T. Mazzucato

The article describes the nature, organization and history of the International cartographic system UTM (Universal Transverse Mercator) used today, together with its extension MGRS, on many topographic maps and GPS receivers. It indicates how to translate the coordinates of these systems into the classic geographic coordinates (latitude and longitude) and vice versa. It mentions also the UPS cartographic system used in the polar areas, not covered by the UTM system.

Elucidatio Fabricae Ususque Astrolabi - John Stöffler - Paris 1553 (Short contribution)

Alessandro Gunella

The author presents his translation of the treatise about construction and use of the astrolabe by J.Stoffler, dated 1553.