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Dials: Reflected
June 2021
Page 37
Page 37
Report on the British Sundial Society's successful virtual conference held via Zoom in April 2021, featuring three noted North American speakers. Talks covered Zarbula and Potey dials in the French Alps, a highly customized ceiling reflection sundial by Woody Sullivan, and Fred Sawyer's theoretical work on Hybrid Peaucellier azimuthal dials designed to eliminate the noon gap.
Dials: Reflected, Mathematics of Dialling, Sundial Design & Layout, The BSS and Members
September 2020
Page 35
Page 35
Describes an unusual Benoy dial (SRN 4074) at Upton Hall, invented by W. Gordon Benoy, that uses a liquid-filled glass cylinder to focus a light beam onto the dial face instead of a shadow. Notes the dial is in need of refurbishment and mentions a second, missing Benoy dial.
Dials: Reflected, Dials: Unusual, Historical Dials
December 2020
Page 36
Page 36
Obituary for Michael Lowne (BSS member 404), who worked at the Royal Greenwich Observatory from 1950 to 1989. Known for his patience and problem-solving, he contributed articles on double horizontal dials, reflecting and refracting sundials, moondials, and solving the operation of a unique 17th-century universal altitude sundial.
Dials: Reflected, Historical Dials, Dials: Double Horizontal
December 2018
Page 20
Page 20
Detailed account of creating an outdoor reflection sundial over five years for a north-facing wall, using a mirror to project a sunspot. The final brass design is a hybrid, using virtual gnomon hour lines for GMT and analemmas marked by planets and asteroids for clock time correction, also celebrating the birth of grandchildren.
Construction Projects, Dials: Reflected, Sundial Design & Layout
December 2012
Page 16
Page 16
This article describes a fused glass noon dial by Adele Christensen for a Gloucestershire client, indicating 12:00 BST on Midsummer's Day via a narrow slit of sunlight. The author also notes a similar Millennium design, the Lockinge Ring by David Harber in Oxfordshire, which uses a mirror for true noon.
Construction Projects, Dials: Noon Lines, Dials: Reflected, Sundial Design & Layout
December 2012
Page 20
Page 20
This article investigates the cross-shaped reflections from double-glazed windows, attributing them to the concavity of the glass panes. Optical analysis reveals radial slope profiles and contour maps, showing a central depression. The phenomenon is likely caused by a partial vacuum inside the units, bending the glass inwards, forming distinct V-shaped patterns on narrow windows.
Dials: Reflected, How Sundials Work
December 2011
Page 50
Page 50
This report details the British Sundial Society's Newbury meeting, featuring talks on topics such as a metal-detected Norfolk horologium, ceiling reflection dials, leap years and calendars, repairing old books, lifting heavy sundials, war memorial dials, and heliochronometers. Exhibits included a cross dial and an equation of time analogue computer, showcasing a diverse range of gnomonic interests.
Dials: Heliochronometer, Dials: Reflected, Historical Dials, The BSS and Members
June 2009
Page 47
Page 47
Describes a unique reflecting sundial where a flat mirror reflects a sunbeam onto a curved wall that serves as the dial plate. The article explains the geometry, calculations, and calibration process for this artistic and scientific instrument located at Tolefors Farm, Sweden.
Dials: Reflected, Dials: Unusual, Sundial Design & Layout
September 2006
Page 140
Page 140
This article provides an update on the Horniman ceiling dial, a reflected sundial installed in a wooden building. It discusses ongoing monitoring and a recent recalibration due to timber movement. An innovative technique using a balloon to cast a shadow and make the light spot visible during low winter sun conditions is also highlighted.
Dials: Reflected, How Sundials Work
December 2002
Page 161
Page 161
Brief note on a modern artistic reflective sundial design named 'Helios'
Dials: Reflected, Dials: Unusual, Sundial Design & Layout
March 2001
Page 9
Page 9
This article details the design and delineation of a reflective ceiling dial at the Horniman Museum, inspired by a sundial trail lecture. It sets out the mathematical formulation for determining coordinates on the dial, explaining how it relates to an equivalent declining, reclining dial. The authors emphasize that reflective dials are not inherently more complex to delineate than other planar sundials, providing formulas for angle and length calculations, and tables of coordinates for various times and declinations.
Construction Projects, Dials: Reflected
February 2000
Page 15
Page 15
Observation of the 1999 solar eclipse via pinhole effects on a reflected sundial at the Horniman Museum.
Dials: Reflected
October 1999
Page 148
Page 148
This article describes a millennium project involving the construction of a tower, 'La Meridiana', near Rome, to house a series of internal sundials. The author designed 10 dials for the walls and ceiling, read by sunlight projected through openings or reflected by a mirror. An experimental dial at his family house achieved accuracy within 10 seconds. The project aims to demonstrate precise time and date measurement, zodiac, altitude, and azimuth, using novel methods for declination, horizon, and meridian establishment.
Construction Projects, Dials: Reflected, Dials: Unusual, Sundial Design & Layout
February 1998
Page 30
Page 30
Describes novel non-shadow dials using reflectors. Parabolic and cylindrical forms generate bright caustic lines on a screen; hour indication follows motion of the cusp or inner edge. Includes formulae, constructional notes and an aperture version using a sundial curve.
DIY Sundial Projects, Dials: Reflected, How Sundials Work, Mathematics of Dialling
October 1990
Page 5
Page 5
This article explores the history and theory of reflected ceiling sundials, referencing figures like Isaac Newton and Christopher Wren. It discusses examples such as the Palazzo Spada in Rome, the Lycee Stendhal in Grenoble, and a unique staircase dial in Saint-Antoine-en-Vienne, along with their design principles and historical context.
Dials: Reflected, Historical Dials, Sundial Design & Layout