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