The azimuth sundial used as a measuring instrument for finding north. The cursor is set for the date, the cursor arm is turned to set the time. The gnomon shadow and cursor are in line.
The Mercat Cross at Inverkeithing in Scotland is a tall stone column that dates from the 14th century. The top of the column has a sundial stone in the form of a cube and a unicorn. Restoration of the whole column is now complete. To re-install the sundial stone correctly we had to find a true north line.
The north line is the direction that shadows will fall at noon, and Noon is the exact time of day when the sun is in the south. Unfortunately the sun doesn’t always shine at noon, so we have to use a measuring instrument. We do have our own precision instrument, which is an azimuth sundial. It has calibrations for the direction of the sun on every day of the year for every hour of the day.
On 10th October 2025, at Inverkeithing, we prepared for the measurement on site, working with Graciela Ainsworth Sculpture Conservation and Restoration. The foundation for rebuilding the column was already in place, so we set the sundial level on the concrete. After waiting for the sun to shine, we moved the cursor to the date on the sundial scale. Then at 12.14pm (BST) equal to 11.14am (GMT) we turned the cursor arm to the time, and rotated the sundial itself until the central gnomon shadow lined up with the cursor. Here, the shadow is on the sun’s line, but the instrument is on the line of north. Marking this direction on the concrete foundation provided the true north reference for rebuilding the column.