September 2008 page 123
Graham Aldred
Celia James

An Analysis of the Vertical Equiangular Sundial

This paper provides a mathematical analysis of James Richard's rare vertical equiangular meantime sundial, designed to resemble a clock with equally spaced hours. It explains the gnomon's upward inclination and daily displacement, allowing for mean time and BST adjustments. The analysis, an alternative to Foster-Lambert theory, aims to stimulate interest in this unusual dial type.
Dials: Foster-Lambert, Dials: Vertical, Mathematics of Dialling, Sundial Design & Layout

March 2007 page 40
Michael Lowne

The self-setting property of dual sundials

This paper examines the self-setting property of dual sundials, typically consisting of a polar-gnomon dial and an analemmatic dial. It explains the astronomical parameters involved, how rotation affects time indications, and calculates the effectiveness of this alignment method at various latitudes and declinations. It also compares the traditional dual dial with an alternative Foster-Lambert reclining dial.
Dials: Foster-Lambert, Dials: Double Horizontal

October 1991 page 24
Fred Sawyer

A Self-Orienting Equiangular Sundial

Fred Sawyer presents a self-orienting equiangular sundial, a modification of the Foster-Lambert hybrid dial, capable of correct orientation without external devices. It functions as both a solar clock and a solar compass, determining true celestial north. The design involves a V-shaped gnomon and two sets of hour-markings, allowing for simultaneous readings of Standard and Apparent time and a straightforward orientation process.
Dials: Foster-Lambert, How Sundials Work, Sundial Design & Layout