Gnomonics

The structure and operating principles of a solar compass conceived and realised at the ENEA Laboratories in Frascati are presented. The optical design, the underlying software and the calibration procedure make this instrument a reliable, stand-alone tool with an unprecedented combination of accuracy and cost-effectiveness. In-field operation gives evidence of azimuth determination capability with an accuracy of 0.01°. Exploitation of built-in sensors of smartphones (e.g. GPS, camera, accelerometer) allowed us to move this technology to popular level, providing everybody with a cheap tool of orienteering, far superior to any magnetic compass, despite a reduced accuracy with respect to the original instrument.

"This paper proposes three new (and tentatively, another two) identifications of sundials in Middle Eastern mosaics of the 5th – 8th century. The author discusses a vignette from the Holy Martyrs’ Church at Tayibat al-Imâm, central Syria, a mosaic panel from the tomb of Georgia and Theodosia in Jerusalem, two
vignettes of Sebastis and Kastron Mefaa from the St. Stephan’s Church at Umm al-Rasas, and a vignette of Jerusalem from the St. George’s Church at Madaba. These mosaics date, respectively, to 442, to the reign of Justinian (527 –565), and to the Byzantine Umayyad era (718). According to the author, these are probably the latest representations of sundials known to date from the Late Antiquity. Until this study, only six representations of sundials on mosaics from the Roman period were known. This paper adds three new items and two hypothetical ones from Byzantine times. It also offers an interpretation of the function of the famous column in Jerusalem, shown on the map of Madaba and the mega-vignette of the Holy City.
Key words: Sundials, Sonnenhuhren, Meridiane, Cadrans solaires, Relojes de sol."

Abstract: In this article, we shall elucidate the use of shadow lengths for regulating prayer times among Zoroastrians, focusing on a part of a Zoroastrian religious book entitled Shāyest Nāshāyest, written in Middle Persian (Pahlavī) language probably around the 9 th c. A.D. Then, we will compare this text with a part of another Persian work entitled Yawāqīt al-þUlūm wa Darārī al-Nujūm which is written in the second half of the 6 th century after Hijra (the 12 th c. A.D.) by Abū Mu¬ammad al-Najjār in Islamic civilization. For this purpose, we will recalculate the given values for the shadow lengths of the gnomon – taken as the height of a man – in both texts and find the best fitted latitudes for them. Finally, we will mention the similarities of the two texts to investigate the possibility of a historical relationship between them. Moreover, the transmission of this timekeeping method among some civilizations will be discussed.

This article presents an edition and brief analysis of the previously overlooked text 'De compositione quadrae', which is transmitted as part of a scientific miscellany assembled at Worcester Cathedral Priory no later than 1140. 'De compositione quadrae' offers hitherto unavailable information on the construction of the so-called quadrans vetustissimus, a version of the universal horary quadrant circulating in Latin Europe during the eleventh and twelfth centuries. It is particularly noteworthy for its description of a graphical method of inscribing the months of the Julian calendar on the quadrant’s cursor, which successfully approximates the sine function that determines the change of solar declination in the course of a year.

The Infinity in the Few Lines: Sundials "Real Time" in our Modern Cities. Sundials are nothing more than a graphical representation, on the Earth, of the apparent motion that the Sun moves along the surface of the ethereal celestial sphere. This immaterial contact between Heaven and Earth is a timeless element of charm that makes sundials, even today, a natural contact object for Art, Philosophy, Geometry, Geography, Physics and Astronomy. These precious artistic goods, often placed in monumental architectures, have the memory of an ancient and valuable knowledge, when the man regulated his work in close connection with the happening of natural diurnal and annual cycles. This research aims to identify a methodology able to establish a dialogue between different fields of knowledge (restoration, geometry, new technology, history of architecture, astronomy and gnomonic) with the main purpose of triggering the diffusion, the communication and the consequent use of sundials, often abandoned.

The present paper examines Borromini’s two sundial-related projects – the timepiece in Urban VIII Barberini’s garden on the Quirinal (1628) and the scientific device intended for the Villa Pamphilj (1644). Sundials in the villas and gardens of seventeenth-century Rome can be interpreted as a confluence of three distinct intellectual currents: first, the tradition of solar imagery and the notion derived from Roman antiquity of the sun as ideological pointer; second, the new trend in scientific research and the contemporary interest in the model of the heliocentric universe; and third, the notion of the pope as timekeeper, fulfilling the role of establishing order in society traditionally assumed by the Catholic Church. The paper seeks to highlight the multivalence of the sundial and the tension between the diverse cultural meanings contained in a seemingly common garden furnishing, and to situate the sundial within the broader context of the history of architecture.

Esta es una traducción del clásico matemático de la cultura China: Zhou Bi Suan Jing. Bajo esta interpretación, se descubre una verdadera cosmovisión desarrollada alrededor del Tao desde un remoto origen hasta su culminación en el siglo II a. C. Este análisis del Zhou Bi se refuerza con gráficas ilustrativas y con propuestas de reinterpretación como aquella de la regla “Thousend li by cun”; misma que lleva al escalamiento del tamaño del Mundo descripto, haciéndolo compatible con el observable. Esta cosmovisión describe un universo formado por un Cielo y una Tierra planos.

The interest here is molded around the concept of ‘gnomonic apprehension’ by percolating it as synonymous to the idea of ‘theoria.’ It follows a dramatization of Thales’ uncovery of the theory of homeothesis (as found with Michel Serres) under a consigned understanding of the concept of ‘apprehension’ coupled with the idea of that which can be called here ‘kairotic sensibility.’

The astonishing case of an Analemmatic Sundial invented and patented in England in the year 1892, and lately patented in Spain in the year 2001 as a "new type of sundial".
The original invention can be seen on the Science Museum of London since 1897.
The "newly invented" and patented sundial can be seen all over Spain.

Peter Bienewitz, also known as Petrus Apianus, is a well-known scholar whose works have been studied in depth. The authors focus on a book by his son Philip, in which a new instrument is described: the so-called Trientis. The Trientis is ascribed by Philip to his father's creations, which can now include also this instrument.

Authors can be contacted at: [email protected]

In this article, we shall elucidate the use of shadow lengths for
regulating prayer times among Zoroastrians, focusing on a part of a Zoroastrian
religious book entitled Shāyest Nāshāyest , written in Middle Persian (Pahlavī)
language probably around the 9th c. A.D. Then, we will compare this text with a
part of another Persian work entitled Yawāqīt al-þUlūm wa Darārī al-Nujūm
which is written in the second half of the 6th century after Hijra (the 12th c. A.D.)
by Abū Mu¬ammad al-Najjār in Islamic civilization. For this purpose, we will
recalculate the given values for the shadow lengths of the gnomon – taken as the
height of a man – in both texts and find the best fitted latitudes for them. Finally,
we will mention the similarities of the two texts to investigate the possibility of a
historical relationship between them. Moreover, the transmission of this
timekeeping method among some civilizations will be discussed.

"Les informations concernant les cadrans solaires de l’Antiquité proviennent de sources multiples: archéologiques, littéraires, épigraphiques et iconographiques. La mosaïque est notamment une source importante permettant de les appréhender dans leur véritable contexte.
Jusque très récemment, le nombre de représentations de cadrans solaires identifiés sur les mosaïques antiques était limité à six cas, tous - à l'exception d'un pavement, de l’époque romaine et situés dans les provinces occidentales du Ier s. av. J.-C au IIIe s.: Torra Annunziata (à côté de Pompéi) et Sarsin (Ombrie, Italie), Broading sur l’Île de White (Grande-Bretagne), Trèves en Germanie, Saint Romain-en-Gal en Gaule et Antioche en Syrie (aujourd'hui en Turquie). Désormais, grâce à de nouvelles identifications, notre catalogue vient de doubler.
Les six mosaïques avec représentation de cadrans solaires identifiés récemment proviennent du Proche-Orient et sont datées du Ve au VIIIe siècle, à l’exception d’une, gauloise, trouvée dans une basilique publique (?) à Grand (IIIe s.). Les cinq mosaïques proche-orientales proviennent des provinces de Syrie Seconde, d’Arabie et de Palestine Première et pavaient des basiliques chrétiennes: Tayyibat al-Imam, Umm al-Rasas (vignette de Sebastis et de Kastron Mefaa), Madaba (vignette de Jérusalem); celle de Jérusalem ornait le sol d’une chapelle funéraire ou d’une tombe.
Key words: Sundials, Sonnenhuhren, Meridiane, Cadrans solaires, Relojes de sol
See: M.T. Olszewski, Cadrans solaires sur trois mosaïques byzantines au Proche-Orient et quelques autres identifications hypothétiques de gnomons géants, Archeologia (Varsovie) 60, 2009 (2012), p. 69-79, pls. IX-XI.
M.T. Olszewski, Les cadrans solaires dans les mosaïques romaines et byzantines (Ier siècle ap. J.-C. - IXe siècle ap. J.-C.), [in:] A. Tomas (ed.), Ad fines imperii Romani. Studia Thaddaeo Sarnowski ..., Warszawa 2015, pp. 449-468
https://www.academia.edu/19421274

Ce livre, écrit par Giancarlo Bonini, retrace la construction, en 2007, d'un ancien et important instrument astronomique, une méridienne à chambre obscure, dans une église du XVIIe siècle à Perinaldo (Province d'Imperia - Italie), lieu de naissance de l'astronome Giovanni Domenico Cassini. L'illustration du fonctionnement de l'instrument ainsi que les méthodes, les techniques et les détails de sa réalisation sont replacés dans le contexte historique de l'évolution de l'organisation sociale, qui relie le gnomon primitif au "Grand Gnomon", aux "cathédrales solaires". Ici, science et religion, besoins et curiosités de l'homme, matérialité et imagination créatrice, se succèdent et se croisent, donnant naissance, comme cela arrive parfois, à de grandes oeuvres. Le texte, tout en limitant l'aspect spécialisé, s'adresse aux amateurs d'astronomie, de mathématiques, de géographie, d'histoire, de science, de religion, ainsi qu'à ... tous les habitués du temps, dont la curiosité les invite à aller au-delà du temps indiqué par les horloges.

L’edificazione della Cattedrale materana in forme romaniche avvenne in epoca tarda, verosimilmente dal 1230 circa al 1270 e nel corso dei secoli la facciata principale,
orientata a Ovest, è divenuta l’icona della città storica, anche per la sua posizione predominante e a favore dei punti più panoramici.
Il nostro interesse però, oggi si concentra sul fianco meridionale del monumento, sul quale si rinviene un gran numero di attestazioni graffite, che si rivelano testimonianze
utili alla comprensione di una serie di dinamiche storiche che agli occhi moderni possono inizialmente sfuggire. Diventando tali segni sempre più flebili, anche a seguito di ogni pulitura, è bene fissare quanti più dati del loro vissuto.