March 2003
Page 3

John Constable's Rainbows Over Salisbury Cathedral and Stonehenge

Analysis of John Constable’s paintings using principles of sundial geometry to determine whether the rainbows depicted are optically accurate and temporally consistent.
How Sundials Work

David M. Colchester

October 1996
Page 13

A Polarized Skylight Sundial

A description of constructing a sundial that uses the polarisation of skylight rather than shadows to tell time, explaining the optical principles, historical references, and potential applications.
Dials: Unusual, Sundial Design & Layout, DIY Sundial Projects

David M. Colchester