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Dials: Equatorial

March 2012 page 14
Mike Cowham
The Dials of Saint-Hippolyte-Du-Fort, France
This article describes a walking tour of the 23 (or more) sundials in Saint-Hippolyte-du-Fort, France. It highlights attractive examples, including an equatorial dial, a church dial, and several made by local ceramic artist C. TINGAUD, noting features like 24-hour systems and Provençal mottoes.
Dials: Equatorial, Dials: Vertical, Historical Dials, Mottoes
June 2012 page 21
Lego Equatorial Dial
Don Rogerson of Red Oak, Iowa (USA) designs sundials using standard Lego bricks. This entry briefly describes an example: a 'Large Equatorial' dial constructed from 1x4 bricks and a 1x2 hinge plate, with grey and white blocks designating hours. Rogerson hopes to interest Lego in producing special sundial sets.
Construction Projects, DIY Sundial Projects, Dials: Equatorial
June 2012 page 43
Another Lego Sundial
This short entry presents another equatorial sundial designed by Don Rogerson using Lego bricks. It is built around a 1x4x5 arch brick, with central blue bricks marking noon and outer bricks indicating 6am and 6pm solar time, resembling the BSS logo.
Construction Projects, DIY Sundial Projects, Dials: Equatorial
June 2012 page 52
Michael J. Harley
New Dials
This article describes a stainless steel sundial at the Nano Nagle Centre in Ballygriffin, Ireland, which is the final 'station' of a 'cosmic walk'. Designed by Jonathan Mason, it features a 3.2-meter high gnomon with a central slit, a 200mm noon gap, and a prism for season indication. It also includes the world represented by a ringed globe and forty clasped hands symbolising intergenerational links.
Construction Projects, Dials: Equatorial, Dials: Unusual, Sundial Design & Layout
September 2012 page 22
John Davis
Lost Bonar Dial Resurfaces (Briefly!)
This article reports the brief reappearance of a 1634 slate equatorial dial by John Bonar, originally from Loudon Castle, Scotland, at a German auction. Unsold, it subsequently disappeared from public view. Despite missing its gnomon and moon volvelle, the dial is considered an important artefact of early Scottish dialling, featuring detailed engravings.
Dials: Equatorial, Historical Dials, Restoration projects
September 2012 page 36
John Davis
Cai Mason
A Medieval Equinoctial Dial Excavated at St James’s Priory, Bristol
This article describes the excavation of a fragment of a medieval equinoctial (equatorial) dial at St James’s Priory, Bristol. Dated pre-1540 and likely late 14th/15th century due to the use of Arabic numerals, it is a significant find that reinforces awareness of early scientific dials in Europe, and is believed to be one of the oldest in Britain.
Dials: Equatorial, Historical Dials
September 2012 page 46
Roger Bunce
An Equatorial Sundial with EoT Adjustment: Update
This article provides an update on an equatorial sundial design with Equation of Time adjustment, originally published in 2009. The Mk.2 version incorporates improvements for public use, focusing on weather protection, increased strength, and enhanced vandal resistance, developed in response to the Austrian Sundial Society's plans to install a version.
Dials: Equatorial, Construction Projects, Equation of Time
December 2012 page 12
Mike Cowham
The Equatorial Dials Of Kloppenburgh & Cremer
The article examines unusual 18th-century equatorial dials by Gerhard Kloppenburgh and Gerhard Cremer, made of gold-plated brass. It details their summer and winter sides, including hour lines, zodiac signs, and global noon times. The author discusses peculiar reversed Roman numerals, possible origins in northern Germany, and an anomaly in numeral thickness.
Dials: Equatorial, Historical Dials, Sundial Design & Layout
December 2012 page 41
John Davis
Helical Sundials
The article discusses helical sundials, particularly one made by Aylmer Astbury. These are a form of equatorial dial, with a brass strip helix marking hours via small holes or a terminator shadow. They can be adjusted for longitude and Equation of Time by rotating the helix on its axis, as explained in a 1992 Bulletin article.
Dials: Equatorial, Dials: Unusual, How Sundials Work, Sundial Design & Layout
March 2011 page 15
Tony Wood
A Sundial and its Provenance
This article describes an equatorial sundial at Weston-under-Penyard, initially believed to be 17th-century due to its inscription. The author's investigation, including a 1932 sales receipt and a Christie's report, reveals it was made by Pearson Page in the early 20th century, highlighting the importance of provenance.
Dials: Equatorial, Historical Dials
September 2011 page 27
Christopher Daniel
Nature Club of Pakistan
This report highlights a successful gnomonical science studies programme by the Nature Club of Pakistan in Lahore and Faisalabad schools with support from the BSS.
Dials: Horizontal, Dials: Equatorial, How Sundials Work, DIY Sundial Projects, The BSS and Members
September 2011 page 35
Aleksandr M Boldyrev
New Dials
Aleksandr Boldyrev describes the creation of an equatorial sundial for the Rosarium of Sokolniky Park in Moscow. Utilizing an antique piece of Italian marble, the dial features three brass gnomons: one for daylight saving time, one for true solar time, and one for solar azimuth. The dial is designed to operate from spring to autumn equinoxes.
Construction Projects, Dials: Equatorial, Sundial Design & Layout
December 2011 page 10
Val Cowham
Jane Walker
David Hindle
Kate Hindle
Robert Sylvester
Geoff Parsons
The BSS Sundial Safari to Le Mans, France. 7-11 September 2011
This report covers the British Sundial Society's 2011 safari to the Sarthe and Perche regions of France, based in Le Mans. The group visited various sundials, historical sites, and chateaux, including a specific mean-time dial in Le Mans and other vertical and mass dials in surrounding villages. The trip offered cultural experiences and opportunities to meet fellow enthusiasts.
Dials: Vertical, Dials: Multi Faced, Dials: Equatorial, Historical Dials, The BSS and Members
March 2010 page 10
Valery Dmitriev
Harriet James
John Davis
New Dials
A collection of short articles describing new sundials. These include an equatorial 'solar acorn' dial in Solar, Russia; a vertical declining dial in Oxford inspired by Christopher Wren; and a mass-produced, flat-packed equatorial 'Sun Disc' from Australia designed for various latitudes.
Dials: Vertical, Dials: Equatorial, Dials: Unusual, Construction Projects
March 2010 page 12
Doug Bateman
An Equatorial Analemmatic and Calendar Sundial, Alicante, Spain
Describes a modern, equatorial meantime sundial on the marina in Alicante, Spain, designed by Juan Vicente Pérez Ortiz. The dial features a 'cut-out' analemma shape and a slot for apparent time, and has scales for both local and time zone time.
Dials: Analemmatic, Dials: Equatorial, Equation of Time
June 2010 page 13
Peter Ransom
Postcard Potpourri 16: Lake Annecy, France
This article features a postcard from 1908 depicting the impressive multiple-dialled structure, L'Unique, on the banks of Lake Annecy, France. Dated 1874 and named in 1876, the dial is credited to Frère Arsène. It features an equatorial dial, multiple gnomons on a 7-pointed star, and various dial plates indicating noon for several European cities and zodiac signs.
Dials: Equatorial, Dials: Multi Faced, Historical Dials
June 2010 page 36
Heiner Thiessen
A Chime Dial
This article introduces the Chime Dial, an equatorial sundial inspired by historic noon cannons, designed to read solar time and provide an acoustic reminder of the sun's journey. It consists of two brass hemispheres and a dial face with five-minute intervals. A Light Dependent Resistor (LDR) inside the sphere triggers a chime when a sunray passes through a narrow gap, marking a pre-set time.
Construction Projects, DIY Sundial Projects, Dials: Equatorial, Sundial Design & Layout
December 2010 page 17
John Ward
Margaret Folkard
Ron Blum
The Benares (India) Sundial in Three Dimensions
This article discusses the Benares Sundial, one of five equatorial sundial observatories built in India by astronomer prince Sawai Jai Singh II in the 18th century to rectify astrological errors. The authors also describe their work with stereoscopic images and an autocyclostereoscope for viewing 3D images without special glasses, including a 1902 stereograph of the Benares sundial.
Dials: Equatorial, How Sundials Work, Historical Dials
December 2010 page 22
A. Galanakis
E. Th. Theodossiou
V. N. Manimanis
The Construction of an Equatorial Sundial with a Reference to Anaximander’s Skiatheron
This article describes the design and construction of an equatorial sundial inspired by Anaximander's 'skiatheron,' aiming to be an operational work of art. Made from matted stainless steel, the dial uses dots instead of Arabic or Roman numerals for a timeless aesthetic. It also details the construction process, including computer design, prototyping, and addressing issues like rust and plate bending.
Construction Projects, Dials: Equatorial, Historical Dials, Sundial Design & Layout
March 2009 page 13
Maurice Kenn
Reader’s Letter
Maurice Kenn shares observations from Brisbane, Australia, contrasting the reliability of his universal equatorial 'coffee-time' sundial and heliochronometer with his UK radio-controlled clock. He notes the significant variation in local apparent noon relative to Eastern Standard Time in Brisbane.
Dials: Equatorial, Dials: Heliochronometer, How Sundials Work
June 2009 page 24
Roger Bunce
An equatorial sundial with EoT adjustment
Details the design and construction of an equatorial sundial that directly indicates clock time (UTC). It incorporates a mechanical cam to automatically apply the Equation of Time correction, and includes adjustments for latitude and longitude. An appendix explains how to design the cam.
Construction Projects, Dials: Equatorial, Equation of Time, Sundial Design & Layout
March 2008 page 43
John Davis
Pat Briggs’ Meccano Models
Showcases Pat Briggs' Meccano models, ranging from simple equatorial dials to complex planetaria and astronomical clocks. It highlights his ingenious mechanisms, including a universal joint for shadow tracking, an Equation of Time clock, and a 'Meccano Analemmagraph' for drawing the analemma, using cunningly-designed gear ratios.
Dials: Equatorial, Equation of Time, Dialling Tools, DIY Sundial Projects
March 2008 page 46
W. S. May
An Equatorial Mean Time Sundial
Describes the design and construction of an 18-inch brass equatorial mean time sundial, incorporating a mechanism to compensate for the Equation of Time. The article details the machining of a groove on a rotatable drum for EoT correction and the careful assembly and alignment of the time-ring and gnomon, calibrated to read GMT directly.
Construction Projects, DIY Sundial Projects, Dials: Equatorial, Equation of Time
March 2008 page 48
Roger Bowling
A Grinling Gibbons Dial
Describes a non-working universal equinoctial ring dial, about 12cm in diameter, incorporated into a 1684 lime-wood carving by Grinling Gibbons. This carving, representing arts and sciences, is located in the saloon of Lyme Hall, alongside other astronomical and navigation instruments, reflecting Sir Richard Legh's interest in the sciences.
Dials: Equatorial, Dials: Unusual, Historical Dials
December 2008 page 159
New Dial
This piece describes a new multiple dial created by Alex Boldyrev for Shevelkovo Village. Carved from Crimean limestone, it features an equatorial dial's upper half and a south-facing scaphe dial in Greek style. It incorporates owls symbolizing Athena and a reconstructed historical mistake in its design, with gnomons made from cold-hammered copper rods.
Dials: Multi Faced, Dials: Equatorial, Sundial Design & Layout, Dials: Scaphe
February 2006 page 14
Norman Darwood
A Moon Dial
This article provides instructions for assembling and using a moon dial. It explains how to determine the moon's phase using the Golden Number and how to rotate the dial to find the current time. The author notes that this dial relies on estimating the moon’s direction rather than casting a visible shadow, due to the moon's light intensity.
Dials: Equatorial, Dials: Unusual, Construction Projects, DIY Sundial Projects, Dials: Nocturnals
February 2006 page 18
Peter Ransom
Origami Sundials
This article details the author's successful endeavour to create origami sundials without cutting or tearing, describing three unique designs. It provides step-by-step instructions for an equatorial dial, explaining the geometric principles behind folding hour lines and constructing a perpendicular gnomon.
Dials: Equatorial, Mathematics of Dialling, Construction Projects, DIY Sundial Projects
February 2006 page 28
Mike Cowham
Dial Dealings
This article reviews notable sundial sales from 2005 auctions and catalogues. Featured items include diptych dials, astronomical ring dials, universal minute dials, and quadrants. The author also discusses a recognised forgery and provides insights into instrument collecting.
Dials: Equatorial, Dials: Portable, Historical Dials
February 2006 page 32
A New Shopping Centre Dial
This article describes a new large stainless steel equatorial sundial, shaped like a Viking longship, installed at the Westwood Cross shopping centre in Ramsgate. The dial also serves as public seating and features large Roman numerals and an Equation of Time graph, although the author notes some elementary numbering and calibration errors.
Dials: Equatorial, Sundial Design & Layout, Equation of Time
December 2006 page 163
Tony Wood
Sundial Delineation using Vector Methods - Part 6 Equatorial Dials
The article describes how the hour lines, declination lines and the sub-style angle are calculated using vectors. There is a summary which includes the assumptions made and the limitations of the method.
Dials: Equatorial, Mathematics of Dialling
March 2005 page 13
W. S. May
Equatorial Equinoctial Sundial
Details construction of a combined equatorial and equinoctial sundial using stacked car engine starter rings, cylindrical and brass components. Describes adjustable latitude setting and a novel gearing mechanism employing concentric eccentric spindles to apply the equation of time correction on two knobs, enabling mean time readings without manual calculation.
Dials: Equatorial, Construction Projects, Equation of Time
March 2005 page 34
John Davis
Sir Isaac Newton Sundial Unveiled at Leicester University
Describes unveiling of a bronze casting of Sir Isaac Newton for the new sundial at Leicester University. Covers lost-wax casting, assembly of multiple bronze sections, dimensional realignment, and recalculation of hour and date lines for new geometry. Discusses site installation, setting for local latitude and polar alignment.
Construction Projects, Dials: Equatorial
June 2005 page 58
Ken Head
Equatorial Sundial by Lake Como, Italy
Report on an equatorial sundial in Domaso, Lake Como. Describes its construction, inscriptions, and unusual alignment to indicate clock time (at noon, inaccurate at other times) rather than true solar time, with observations of performance and speculation on design choices.
Dials: Equatorial, Historical Dials
December 2005 page 154
Graham Stapleton
‘Timekumpas’ - the smallest heliochronometer?
This article introduces the "Timekumpas," a small, cigarette-lighter-sized equatorial dial patented in 1926. While it lacks precision due to its size, it is notable for being a universal instrument designed to allow for latitude, longitude, equation of time, and magnetic variation, making a "noble effort" to create a sophisticated, portable standard time indicator.
Dials: Equatorial, Dials: Heliochronometer, Dials: Portable, Historical Dials
December 2005 page 160
Graham Aldred
The Lyme Hall Horizontal Equinoctial Sundial
This article details the discovery and reconstruction of a unique 1683 combined horizontal equinoctial sundial at Lyme Hall. The author describes deciphering the inscription "R Legh 1683," examining its robust bronze construction and innovative two-hole sight/screen system. The article also explores the dial's historical context, its owner Richard Legh, and a possible link to George Gibbs's Helio-Chronometer.
Dials: Equatorial, Dials: Horizontal, Dials: Unusual, Historical Dials, Restoration projects, Sundial Design & Layout
September 2004 page 91
Heiner Thiessen
Vial Dial
Description and design of an equatorial ‘vial’ ring dial that combines a planisphere with a sundial. Uses a spirit-level alidade and a rotating outer ring to read local apparent time for any longitude, and to estimate sunrise, sunset and the locus of solar midnight across longitudes.
Dials: Equatorial, How Sundials Work, Sundial Design & Layout
September 2004 page 118
Doug Bateman
Equatorial sundial unveiled by the Queen
Report of a ceremonial unveiling of a new equatorial sundial: description of the dial type, event context and public/promotional aspects of the installation.
Dials: Equatorial, The BSS and Members
March 2003 page 20
The Marlow Dial
Correction and image for a previously published article on the Akeler Sundial at Marlow, showing its garden setting.
Dials: Equatorial, Sundial Design & Layout
September 2003 page 108
Tony Wood
The Benoy Dial - Part 1
The first part of an article on a unique 'New Optical Dial' invented by W. Gordon Benoy. It's a sundial that tells time with a beam of light rather than a shadow. The article describes its construction, its weight, and some technical details including using a glass cylinder filled with water containing anti-freeze.
Dials: Equatorial, Dials: Unusual
December 2003 page 175
Tony Wood
The Benoy Dial, Part Two
Continuation of a discussion of an innovative dial, focussing light through a cylinder onto an equatorial dial plate
Dials: Equatorial, Dials: Unusual
September 2002 page 115
Margaret Stanier
The Twentieth Century
An essay reflecting on the evolution of sundial making and the Society's activities during the 20th century, highlighting significant developments and personalities.
Dials: Bifilar, Dials: Equatorial, Dials: Heliochronometer, Dials: Unusual, Historical Dials, The BSS and Members
December 2002 page 141
Heiner Thiessen
Sunrise Dial
Description of an interactive, educational sundial model representing Earth and showing local apparent time, sunrise/sunset, solar declination, and more.
DIY Sundial Projects, Dials: Equatorial, How Sundials Work
December 2002 page 146
Doug Bateman
The 'Akeler' Equatorial Dial: Relocated in Marlow
Detailed account of the design, relocation, and symbolism of Edwin Russell’s large equatorial dial now installed in Marlow, including technical specifications.
Dials: Equatorial, Dials: Polar
December 2002 page 168
Len Burge
The Crowan Dial: First Impressions
Observations on an unusual slate dial-plate from Crowan, Cornwall, including physical description and preliminary thoughts on its age and type.
Dials: Equatorial, Historical Dials
March 2001 page 42
Margaret Stanier
The 'Universal Equinoctial' Sundial, the BSS Emblem
This article explores the "Universal Equinoctial" sundial, highlighting its significance as the emblem of the British Sundial Society. It discusses the historical context and design principles of this type of sundial, explaining its functionality and why it was chosen to represent the BSS.
Dials: Equatorial, Sundial Design & Layout, The BSS and Members
June 2001 page 65
Andrew McVean
Uttoxeter Millennium Monument
Describes the Uttoxeter Millennium Monument, a large stone disc featuring a solar system theme and an armillary sundial. Conceived to inspire exploration and celebrate the town, it incorporates local craftsmanship, planetary representations, and embedded plaques documenting its creation and sponsors. A time capsule is also concealed within the monument.
Construction Projects, Dials: Equatorial, Dials: Unusual
June 2001 page 73
Sven Olof Larsson
A Stardial
The article presents the Stardial, an innovative device functioning as an equatorial sundial by day and a simplified astrolabe by night. Designed for simplicity, accuracy, and originality, it enables automatic conversion from local solar time to clock time and provides methods for precise time-telling using bright stars and even the moon.
Dials: Equatorial, Dials: Unusual, Dials: Astrolabe, DIY Sundial Projects, Dials: Nocturnals
September 2001 page 127
Armillary Sphere in Cheadle, Cheshire
An armillary sundial, commemorating the Millennium, was recently unveiled in Cheadle, Cheshire. Designed and made by local blacksmith Jim Plant from iron cart-wheel tires, it also honours astronomer Miss Mary Adela Blagg. The sundial's unveiling was attended by BSS President Sir Francis Graham-Smith.
Construction Projects, Dials: Equatorial, Dials: Unusual
September 2001 page 129
Maurice Kenn
Sundial or Garden Ornament
This article discusses an inexpensive armillary sundial widely advertised as "Classic Art For Your Garden" but designed for Latitude 38° N. It explains how to modify such a dial for correct use in the UK (approx. 52° N) by tilting its main body or by physically removing and reattaching elements, enabling it to indicate local solar time.
DIY Sundial Projects, Dials: Equatorial
February 2000 page 20
David A. Young
A Remote Reading Sundial
Design and construction of an electronic equatorial sundial with phototransistors and LED display for remote indication of time.
DIY Sundial Projects, Dials: Equatorial, Dials: Unusual
October 2000 page 125
Sundials for the Year 2000 AD
Showcase of sundials commissioned or constructed to commemorate the millennium year.
Dials: Analemmatic, Dials: Equatorial, Dials: Horizontal, Dials: Vertical, The BSS and Members
February 1999 page 47
Mike Shaw
Journal Review
This review covers two issues of *Compendium*, the NASS journal. It highlights articles on a 'Witch's Sundial', various sundial designs (conical gnomon, Ptolemaic coordinates, cycloid gnomon, split analemma), and 'Sightings' features on notable dials, concluding with a report on the NASS Fourth Annual Conference.
Dials: Equatorial, Book Reviews, Sundial Design & Layout, Equation of Time
June 1998 page 16
Margaret Stanier
Bernhardt Dials
This article describes the distinctive equatorial sundials designed by modern German artist M. Bernhardt. These feature a polished aluminium gnomon pointing towards Polaris, and an hour scale calibrated for mean time, incorporating the equation-of-time correction within the gnomon's outline. Interchangeable gnomons allow for seasonal adjustments.
Dials: Equatorial, Dials: Heliochronometer, Dials: Unusual, Equation of Time, Sundial Design & Layout
April 1997 page 53
B. D. Yallop
Moving a Reclining Equiangular Sundial to Another Site
A description of the challenges and methods involved in relocating a reclining equiangular sundial, ensuring accuracy and preservation.
Dials: Equatorial
October 1997 page 51
Doug Bateman
More Sundials of Hesse, Germany
This section provides photographs of various sundials in Hesse, Germany, including a stone equatorial dial by Kieling, a vertical declining dial by Schaldach, a mass dial on a church buttress in Steinau, and a sundial in a park in St. Goarshausen.
Dials: Equatorial, Dials: Mass Dials, Dials: Vertical, Historical Dials
June 1996 page 22
Maurice Kenn
Simple Sundials Seen on Safari
A personal travelogue documenting sundials discovered in Canada, Australia, and Singapore, including armillary and equatorial dials, with notes on design inspiration and memorial contexts.
Dials: Equatorial
June 1995 page 36
Christopher Daniel
A Modern Reproduction of an 18th Century Universal Equnoctial Sundial
An article about recreating historical sundials using modern methods, reflecting on the balance between authenticity, materials, and function.
Dials: Equatorial, Dials: Portable, Restoration projects
October 1995 page 27
Maurice Kenn
A Large Translucent Universal Equatorial Sundial
A technical and descriptive account of a large equatorial sundial made from translucent materials, designed for broad geographic usability and visual impact, including discussion of its structure and application.
Dials: Equatorial, Dials: Unusual
June 1994 page 11
John Moore
Ring Dials
A comprehensive study of three classic types of ring dials: poke dials, equinoctial ring dials, and astronomical ring dials. The article examines their mechanical function, historical development, geographical usage, and craftsmanship, with detailed illustrations and commentary on their strengths and limitations in practical sundialling.
Dials: Equatorial, Dials: Portable, Historical Dials
June 1994 page 37
Maurice Kenn
A Large Translucent Universal Equatorial Sundial
This article presents the design and construction of a large equatorial sundial made with translucent materials. The dial is universal, meaning it can be used at any latitude, and is designed to be both decorative and scientifically accurate. Its practical applications and display potential are discussed.
DIY Sundial Projects, Dials: Equatorial
October 1994 page 14
John Moore
The Augsburg Dials
This article explores the history and characteristics of sundials produced in Augsburg, Germany, particularly from the 17th century onwards. It notes Augsburg's reputation for metalworking and clockmaking, which influenced the development of ornate and complicated early sundials. The article describes the mass production of "universal equinoctial dials" from around 1700, their common design, and the incorporation of compasses and latitude lists for European towns. It also highlights finer versions made by Johann Martin and Johann Willebrand, including unique "crescent dials" and "string gnomon dials," and provides a list of known Augsburg sundial makers.
Dials: Equatorial, Dials: Portable, Historical Dials
February 1993 page 28
Robert A. Mills
An Unusual Variety of Equatorial Sundial
This article describes an unusual equatorial sundial without a fixed gnomon, featuring a transparent plastic hemisphere. It illustrates the Sun's apparent path and declination throughout the year, explaining how to determine sun time, altitude, azimuth, and declination on any given date using this instrument.
Dials: Equatorial, Dials: Scaphe, Sundial Design & Layout
February 1992 page 19
H. R. Mills
The Azimuth Dial
This article describes the azimuth dial, a type of horizontal dial with a vertical style, derived from the equatorial dial formula. It explains that while a vertical style at the center of a horizontal circle cannot show time correctly throughout the year due to declination changes, projecting an equatorial circle onto a horizontal plane forms an ellipse for the hour lines. The article provides the formula for the shadow angle and suggests this as a useful project for understanding geometry and for practical marking in playgrounds or gardens.
DIY Sundial Projects, Dials: Analemmatic, Dials: Equatorial, Dials: Horizontal, Mathematics of Dialling
February 1992 page 36
Letters to the Editor
This section contains several letters. H.R. Mills provides mathematical formulae for an analemmatic dial, J.G. Freeman describes the bifilar sundial with two horizontal wires, and Alex Monroe encloses a photograph of his portable equatorial dial. M.J. Cowham contributes notes on John Worgan's work, highlighting a distinctive English Rose design on his instruments.
Dials: Analemmatic, Dials: Bifilar, Dials: Equatorial, Dials: Portable
June 1992 page 21
Allan A. Mills
Helical Sundials
This article introduces helical sundials as a variation of the equatorial dial, where the receiving surface extends axially along the gnomon in a helix. It describes a prototype by John Singleton, a monumental example in Lerida by J. Masuet, and Piet Hein's design at Egeskov Castle. There are two types: the first has a gnomon casting its shadow, the second uses the shadow cast by the other part of the helical strip. The article explains their operation, with the light/dark boundary marking time and hour markings set by the pitch.
Dials: Equatorial, Dials: Unusual, Sundial Design & Layout
February 1991 page 6
George Wyllie
A Cross Dial for a Scot.
Describes the design of Cross or Star dials, focusing on the concept of the equatorial notch, which has surfaces parallel to the Earth's polar axis. The shadow cast by the outer edge of the notch onto the opposite surface is used to indicate time. The article provides details on the design and depth required for such dials, noting that each notch effectively functions as a separate dial.
Dials: Equatorial, Dials: Polar
February 1991 page 11
Colin McVean
One Way of Looking at It, Equatorial and Polar Dials.
Equatorial and Polar Dials explores the principles behind these two types of sundials. The article also covers the Equation of Time and how to account for longitude to tell Greenwich Mean Time with a sundial.
Dials: Equatorial, Dials: Polar, Mathematics of Dialling
October 1991 page 13
Gordon E. Taylor
The Dials of Bonar
This article, a summary of a lecture by Mr. Taylor, examines four equatorial sundials made by John Bonar between 1623 and 1634. These dials feature poetry, zodiac signs, moon age, and compass points with port names, indicating their use for tidal calculations rather than just timekeeping. The article notes Bonar's errors in gnomonics despite his poetic skill and details the current locations of the surviving dials.
Dials: Equatorial, Historical Dials
October 1991 page 16
René R.-J. Rohr
The Da'ire-Yi Mu'Addil
Rene R.-J. Rohr introduces the 18th-century Islamic instrument known as the "da'ire-yi mu'addil" (equatorial circle), used for determining daily and nightly prayer times. Driven by religious prescriptions, Islamic scientists developed sophisticated astronomical and mathematical methods. This instrument, although not mathematically precise, allows for the determination of prayer times, especially night prayers like isha and subh, through observation of the sun and moon's positions.
Dials: Equatorial, Historical Dials, Dials: Nocturnals
October 1991 page 28
Fer J. de Vries
A Sundial for the Blind
Gerard Sonius developed a sundial for the blind, located at the Bartimeus blind institution in Zeist, Netherlands. This equatorial rotating dial features figures in relief and an electronic device that emits a sound when pointing to the sun. Marks for summer and winter time allow blind users to determine the time in 5-minute intervals, with explanations provided in Braille and print.
Dials: Equatorial, Dials: Unusual, Sundial Design & Layout
October 1991 page 33
Maurice Kenn
Sundials can be simple and legible
Maurice Kern describes his simple, legible sundial made from commonplace materials, featuring a translucent semi-cylindrical dial and a conventional gnomon. Designed for readability from multiple angles, it indicates solar time and can be adjusted for local mean time or summer time using the Equation of Time, highlighting a frustration with complex and indistinct conventional dials.
Dials: Equatorial, Dials: Unusual, Sundial Design & Layout, DIY Sundial Projects
© The British Sundial Society: 2025