Sundial in Woodbridge, Suffolk

I first became interested in sun-path predictions in the 1970s. Knowing where the sun would rise or set was very useful to a photographer like me. This led me to an interest in sundials, and in 2014 after becoming aware of the introduction of sundial software I decided to try and make one.

I was advised by a well-known sundial maker to start with a simple horizontal dial, but as I enjoy a challenge I decided to go as far as I could with a vertical dial for the south-facing wall of my house.

I then saw the Dolphin dial at Greenwich, which I found very impressive, and decided to follow the Analemma route, which unlike most dials corrects Solar Time to Mean Time. The calculations also correct for the particular Latitude and Longitude of the dial. Several years later, after several trials, I have the dial you see here. The construction of the dial and the many trees surrounding the house limit the number of hours it can depict, but it does show Greenwich Mean Time and British Summer Time to within one minute, and the Signs of the Zodiac, the Solstices and the Equinoxes to an accuracy of one or two days.

The accuracy was not improved when I was having some house repairs done, and a scaffolder accidentally hit the gilded Gnomon with a large iron pole. Although I have repaired it, some further tweaking may be beneficial.

There are many things that could be improved, but as my first completed dial I am quite pleased with it. I find it reassuring that some things in this crazy world are predictable, even over hundreds of years. It is more reliable than my Rolex and generally more accurate, as errors don't build up over time, but of course only when the sun is shining.

Instead of calendar months I chose to show the signs of the Zodiac as they align more closely with the Solstices and Equinoxes, as used in the Meridiana in the Basilico of San Petronio in Bologna, designed by Cassini in the seventeenth century. I based the Zodiac symbols on those used when it was reconstructed in 1776. They advance in an anticlockwise direction throughout the year.

The Zodiac divisions are marked in Green for the first half of the year, suggesting Spring, and Orange for the second half of the year, suggesting Autumn. To read the dial you look for the Sun's image, and depending on the season, use the Green or the Orange part of the nearest Analemma (a 'figure of eight'), following this to the top or the bottom of the curve to read BST or GMT as appropriate.

The dial is made from 20mm thick varnished marine ply, surrounded by an aluminium frame, painted and covered with Dutch Metal leaf and then varnished. The Gnomon is made from copper rod and hand cut copper sheet gilded with gold leaf. The numerals and Analemmas are hand painted, the lettering is made from machine cut vinyl, from a computer file. The Zodiac signs are hand cut from vinyl sheet. The perspective on the lettering was done with the help of Adobe Photoshop.

I am very grateful to the BSS for their monthly publications which are an inspiring source of useful information.

One day before summer solstice