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November 1989
The articles link to the specific page in a PDF optimised for speed. If you want the whole issue, you can download it here, but the files from earlier years can be quite large.
November 1989
Page 2
Page 2
The author explores applying the analemmatic dial principle to vertical planes, contrasting it with the more common horizontal version. The article provides the trigonometric calculations necessary for constructing such a dial on a vertical declining plane, detailing how to find the sub-style to meridian, the dial's "latitude," and the difference of meridians. It describes the layout process involving primary and minor axis circles to generate hour points and arcs for zodiacal signs, explaining why a movable gnomon is impractical for vertical planes and instead a horizontal rod is used. The dial is presented as a philosophical exercise, a functional piece for those interested in the Zodiac, or an aesthetic wall ornament.
Dials: Vertical, Dials: Analemmatic, Mathematics of Dialling
November 1989
Page 5
Page 5
The construction of sundials is discussed, with references to available books on the subject. Several books on sundial construction are mentioned including works by Winthrop W. Dolan, Christopher St. J. H. Daniel, and Peter I. Drinkwater. Delves into practical considerations such as selecting dial types based on site orientation and potential obstructions, which can significantly limit the hours indicated. It describes methods for finding the true meridian and determining latitude, as well as calculating local solar time differences and applying the Equation of Time for accuracy. Tips on personalising dials with mottoes are given, alongside advice on design elements like borders and additional indications, with a caution that too many details can make a dial confusing. The importance of using durable materials that can withstand the climate is emphasised, contrasting permanent materials like bronze with less resilient ones
Book Reviews, Sundial Design & Layout
November 1989
Page 7
Page 7
This article examines sundial inscriptions, or "posies," from a manuscript by John Parmenter, a priest from the 17th century. The article examines thirty-three sundial mottoes and provides interpretations of their meanings
Mottoes
November 1989
Page 11
Page 11
Advice is provided on how to photograph sundials, including considerations for equipment, lighting, and composition. The article suggests taking multiple shots, including a general view of the building and a close-up of the dial.
November 1989
Page 12
Page 12
Describes a large public sundial installation in Madrid, located at the Puerta de Toledo within the old Fish Market. This series of substantial dials, calculated by Juan Jose Caurcel and drawn by Alberto Corazon, includes a vertical dial with Zodiac signs, a horizontal dial, an equatorial-armillary dial, four polar dials with the Equation of Time, and two lunar dials for night hours.
Historical Dials
November 1989
Page 13
Page 13
An extract from William Stukeley's diary mentions a "spot dyal" invented by Gilbert Clark, which shows the time within a room using a ray of sunlight
November 1989
Page 14
Page 14
Advice is provided for those who are beginning to search for sundials, including where to look and what equipment to bring.
November 1989
Page 15
Page 15
Describes a 1576 manuscript related to Lord Burghley detailing a complex sundial on a geometric body. This body is composed of triangular and hexagonal planes, with three of each type containing dials. The hexagonal dials include a "Meridionall Inclinatorye" face and two "declinatory Hexagonalls," which are noted as particularly difficult to construct. The piece lists the various indications marked on these dials, such as vulgar and unequal "Planet hours," Zodiac signs, Azimuths, and Almicanteras, as well as their general uses like determining sunrise/sunset, sun altitude, and celestial positions.
Dials: Multi Faced
November 1989
Page 16
Page 16
A novel sundial system that uses fibre optics to display the time remotely. The system comprises a "sensor unit" placed in direct sunlight and a "display unit" located indoors, linked by flexible fibre optic cables. The sensor unit utilises a lens to focus sunlight onto a screen fitted with fibre optic ends positioned at five-minute intervals. These fibres transmit light to the display unit, which shows a moving point of light on a circular screen resembling a clock face. The system includes adjustments for latitude and Summer Time, and an extra fibre provides a double spot indication on the hour. The editor adds that this optical design, based on Benoy's patent, can indicate time even in hazy conditions and offers improved accuracy and contrast.
Dials: Unusual
November 1989
Page 24
Page 24
