December 2012 page 16
Tony Wood

Summertime Noon Dial

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
Michael Lowne

Window Reflections

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
Frank Coe

BSS Newbury Meeting – 24 September 2011

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
Dina Hviid
Curt Roslund

A novel reflecting dial in Sweden

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

March 2008 page 40
Tim Hunkin

Sundials

Reproduces Tim Hunkin's 'Rudiments of Wisdom' cartoon strip on sundials from the Observer newspaper. It offers a general introduction to sundials but points out historical inaccuracies, such as the Roman, not Egyptian, use of obelisks as gnomons and details regarding Charles Wheatstone's polarised light sundial.
Dials: Reflected, Historical Dials, How Sundials Work

September 2006 page 140
John Moir

Update on the Horniman Ceiling Dial

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

Helios

Brief note on a modern artistic reflective sundial design named 'Helios'
Dials: Reflected, Dials: Unusual, Sundial Design & Layout

March 2001 page 9
Ray Ashley
John Moir

The Horniman Museum Reflective Ceiling Dial

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
Paul Rainey

A Solar Eclipse Seen on a Reflected Ceiling Dial

Observation of the 1999 solar eclipse via pinhole effects on a reflected sundial at the Horniman Museum.
Dials: Reflected

October 1999 page 148
Mark Lennox-Boyd

La Meridiana: A Millennium Project

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
Michael Lowne

Reflecting Sundials

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
René R.-J. Rohr

On Reflected Ceiling Dials

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