Page 1

Dialogue

This section provides various updates, including news about the Spanish sundial association's bulletin "Analemma" and the Dutch "Der Zonnewijzerkring" bulletin. It announces the Essex Clock Fair where the BSS will be represented, details a BSS computerised dial listing, and outlines the BSS's collaboration with Jodrell Bank for an Educational Resources Centre and sundial installations. It also includes an offer for members to advertise wants/surplus items and announces the XII Scientific Instrument Symposium.
The BSS and Members

Page 3

From the Chairman's Pen

The chairman discusses the British sundial heritage, noting its rapid decline due to neglect and vandalism. He emphasizes the importance of the Society's ongoing work to catalogue, record, and research sundials in Britain for their preservation and restoration. He also cautions members about offering restoration advice without professional expertise and highlights the need to identify outstanding sundials for national protection.
The BSS and Members

Christopher Daniel

Page 4

The Secretary's Notebook

The Secretary reports on the successful nomination of all current and three new council members, avoiding an election. He encourages more members to volunteer for council or sub-committee roles, acknowledging the challenge of geographical spread. The note also announces the AGM as a one-day event and the annual conference in Bath, plus an update on restoration efforts for a Gloucester church dial and the ongoing complexities with the Collyweston dial due to English Heritage involvement.
The BSS and Members

David A. Young

Page 5

Astronomical Endeavours and Highlights under Allah's Sun

This article explores Islamic astronomy's role in determining prayer times, particularly the challenge of twilight in higher latitudes like Brussels where true night is absent around summer solstice. It discusses the use of astrolabes and the historical importance of observatories like Maragha and Samarkand, highlighting their monumental instruments and the Koran's influence on precise astronomical observations. It also mentions Maharaja Jai Sing II's five observatories in India, especially the Jaipur Great Samrat Yantra.
Dials: Astrolabe, Mathematics of Dialling

René R.-J. Rohr

Page 11

Moondials

This article reviews historical techniques for telling time by the moon, noting their limited accuracy due to the moon's irregular movements and the need to convert lunar time to solar time. It describes methods like using correction tables (e.g., Queen's College, Cambridge, or Rene Rohr's diagram) and specific moondial instruments (Oronce Fine, Bion). The author also proposes a new model of lunar dial, adapting a horizontal sundial with "lunar hour lines" as spiral curves.
Dials: Unusual, Dials: Nocturnals, Sundial Design & Layout

Rear-Admiral (Rtd) Girolamo Fantoni (Italy)

Page 16

Foster's Diametral Sundial

This article describes Samuel Foster's diametral sundial, a horizontal dial with a movable stile where hour-points lie on a straight line. Its unique feature is that the shadow becomes retrograde daily at a selected hour, allowing for the recreation of the Biblical miracle of Ahaz's dial. The article provides construction details and mathematical justifications for this special form of elliptical dial, also attributing the original discovery of the circular hour-arc dial to Foster.
Dials: Unusual, Mathematics of Dialling, Sundial Design & Layout

Fred Sawyer

Page 18

Sundial Alignment by the use of the Pole Star

The article proposes an improved method for aligning a sundial gnomon using Polaris, building on previous discussions by Mills and Taylor. It suggests a sighting device made from sheet metal with an eye aperture and a circular target. The method relies on knowing Polaris's angular distance from the true pole and its position relative to the star Beta Ursa Minor (f3 UMi), aiming for an accuracy within 0.25 degrees by aligning Polaris on the target edge opposite f3 UMi.
Construction Projects, Dialling Tools, Mathematics of Dialling

Michael Lowne

Page 19

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

H. R. Mills

Page 22

A Sundial Delineator

This article introduces a portable sundial delineator that simulates the sun's movement using a point-source lamp to project shadows. It allows for plotting hour lines on any surface, including irregular ones, by setting the gnomon at the correct latitude and revolving the lamp at 15-degree intervals. The device, suitable as a teaching aid, can also simulate declination for "dial furniture" like equinoxes and solstices by adjusting the lamp's height.
Dialling Tools, Sundial Design & Layout

Allan A. Mills

Page 23

Sundials used for Navigation

This article highlights the useful adoption of sundials for navigation in the 20th century, particularly in situations where magnetic compasses were unreliable. It cites examples like Admiral Byrd's "Sun Compass" for polar flights and the "Astro-Compass" used in RAF aircraft during WWII. It also mentions Brigadier Ralph A. Bagnold's "Sun-Compass" for desert exploration and Gerald Dunn's "Cruiserfix" for yachtsmen, demonstrating the sundial's value as a navigation tool.
Dials: Portable

Maurice Kenn

Page 24

The Miracle of Ahaz

The article clarifies the Biblical account of the "Dial of Ahaz," explaining that the original Hebrew text refers to "steps" and a "staircase" rather than a sundial with "degrees." It discusses how medieval illustrations, like Holbein's, misinterpreted this, depicting a hemicycle-like device. The author also notes an adjustable Jewish hemicycle described in a 1650 translation, which could tell time by both the sun and the moon.
Dials: Hemispherical, Historical Dials

Peter I. Drinkwater

Page 25

PROFILE: Harriet Wynter

This profile introduces Harriet Wynter (born Molly Rich), a prominent figure in the scientific instrument world. It traces her career from working in an electrical instruments factory during WWII to becoming an antiques dealer specializing in scientific instruments. She co-authored a book on scientific instruments, publishes numerous catalogues, and is about to write a book on portable sundials, having recently been made a Liveryman of the Worshipful Company of Scientific Instrument Makers.
The BSS and Members

Charles K. Aked

Page 26

The 1991 Cambridge BSS Conference

This report details the 1991 BSS/Zonnewijzerkring Conference at Queen's College, Cambridge. Highlights included lectures on the split-gnomon dial by Hans de Rijk, Gordon Taylor's equiangular sundial, and Fer de Vries on gnomonics. Delegates toured Cambridge sundials, including an ancient scratch dial and multi-faced dials. Workshop sessions covered dial making by computer, scratch dials, portable sundials, and sundial education.
The BSS and Members

Mrs. A.D. Hannekuyk

Page 28

Cambridge Lecture "Dialling Literature"

Charles K. Aked discusses the vast and under-catalogued field of dialling literature. He notes the absence of a comprehensive bibliography and shares his own ambitious, ongoing project to compile one, which has already uncovered thousands of entries. The lecture covers the historical evolution of dialling texts, the challenges of translation and accuracy, and the value of modern works over older, often complex and specialized treatises.
Book Reviews

Charles K. Aked

Page 33

Cambridge 1991 Lecture "Gnomonics"

Fer de Vries presents a mathematical method for calculating sundial lines and for determining the inclination and declination of a dial plane. He defines various coordinate transformations needed to convert the sun's position into shadow-point coordinates on any surface, applicable globally. The procedure can also be reversed to find time and date from a shadow, or to determine the dial's orientation from observed shadow points, and is useful for designing mirror or submersible dials.
Mathematics of Dialling, Sundial Design & Layout

Fer de Vries (Netherlands)

Page 35

What is Time?

This is a philosophical poem reflecting on the nature of time. It describes time as a relentless, forward-only motion that encompasses human existence, contrasting humanity's fleeting life and attempts to leave a mark with time's inexorable flow. The poem touches on the building of clocks and recording days, but ultimately emphasizes time's indifference to human endeavors and its continuous, unchanging presence.

Harriet Wynter

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

Page 38

Dial-ectic

Charles K. Aked explores the etymology and various uses of the word "dial," prompted by a member's use of "dial-ectic." He discusses its Latin origins ("dies" for day) and its evolution from "diurnal wheel" in clockwork to "sundial." The article critiques dictionary definitions for being too loose and traces historical references to "dial" in literature from the 15th to 19th centuries, including its figurative senses and use in distinguishing from mechanical clocks.

Charles K. Aked

Page 39

Editor's Fare

Charles K. Aked reflects on the unexpected growth and success of the BSS Bulletin since its inception as a small newsletter. He highlights the rapid increase in membership, the transition to printed issues for clarity and illustrations, and the challenges of rising postage costs. The editor notes the high erudition of contributors, the society's ability to cater to diverse interests (including mass dials and computer programs), and solicits member contributions and suggestions for improvements.
The BSS and Members

Charles K. Aked

Page 40

A Protest Sundial

This article describes a "protest sundial" unveiled in Sarajevo, Yugoslavia, on September 6, 1991. Carved into a granite slab, it features standard astronomical content but incorporates a modified sketch of the former Berlin Wall and a satirical drawing by Honoré Daumier depicting Chronos with a cannon. The creators named it a "protest sundial" as an acerbic comment on the gloomy everyday life in Yugoslavia, reflecting political commentary through gnomonics.
Dials: Vertical, Mottoes

Milutin Tadic