hour lines

Calibrating a new obelisk sundial in stone

Inclined test dial facing east

This dial stone is a test piece for the new obelisk sundial, and is on a board at the correct angle for one of the faces of the obelisk. It faces East and inclines 61° to horizontal so the shadow of the temporary plastic gnomon will show the time.

Obelisk sundials carved in stone were popular in Scotland in the 17th and 18th centuries. Quite recently stonemasons in Fife have done the work to carve a new obelisk sundial for one of their clients. Its dials have remained blank for mathematical calibration. Macmillan Hunter are responsible for the calibration and have supplied detailed dial instructions and drawings for the mason to use together with the required set of geometric bronze gnomons. Continue reading

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Skein of geese art installation at RSPB Loch Lomond

Skein of geese art installation at RSPB Loch Lomond

Skein Dial, Hannah Imlach, 2023. Art installation and sundial at RSPB Loch Lomond, with the artwork constructed in Corten steel in the foreground and the towering mass of Ben Lomond in the distance. This is a remarkable piece that captures the ephemeral impression of geese in flight and shows the dates when they migrate by a sundial shadow. Photo: Hannah Imlach

In November 2022 visual artist Hannah Imlach approached us to talk about an art installation she had in mind for the RSPB Nature Reserve at Loch Lomond. The reserve is a prime site where Greenland White-fronted geese come and overwinter. Hannah’s concept for her artwork was a visual image of skeins of geese flying in the sky combined with a sundial showing the times when the geese arrive and leave. White-fronted geese migrate from Greenland in the autumn and return there in the springtime to breed. Continue reading

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Restoration of a small brass garden sundial from the 1930s

Brass sundial from the 1930s restored with a new gnomonThis small brass garden sundial had lost its gnomon. It is dearly loved by its owner who has known it since childhood, and she wanted to have it restored. As often happens at different times the family moved home and the sundial moved too. Continue reading

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What is the declination of the wall for a sundial

The diagram illustrates a method for calculating wall declination.

Knowing the declination of the wall (WD) is important for designing a sundial. The basic calculation is azimuth angle (AA) minus protractor angle (PA) plus 90°. You can repeat your measurements for accuracy. Do ask for help if you are unsure.

“What is the declination of the wall for a sundial?” A stone sculptor asked us just this question recently . It is a good question because you must know the declination if you are making a sundial that is accurate for the wall. The sculptor was not confident about their own measurements and calculations so they asked us for help. Continue reading

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