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Armillary sundial reads summer solstice by a ball shadow at noon

At the summer solstice the armillary sundial casts a shadow of the ball at noon

At summer solstice the ball on the upper tropic ring casts its shadow exactly onto the opposite ring below. The upper tropical ring is the tropic of Cancer and lower ring is Capricorn.

The armillary sphere dates back to ancient times when astronomers created their own vision of the earth and the heavens. The idea still works today and our own design creates a sundial with a special feature of two balls that mark the passage of the seasons by their shadows. One of the balls reads summer solstice. This is the high point of the year when the sun is highest in the sky.

The balls are carefully positioned at the meridian point on two tropical rings, the upper one on the Tropic of Cancer and the lower one on the Tropic of Capricorn. When the sun is at noon, the highest point of the day, the ball on the Tropic of Cancer casts its shadow right across the sundial to the opposite tropical ring, exactly at summer solstice. This year the actual time of the solstice is 9.13am GMT (10.13am BST) on 21st June 2022. You will find a full explanation of summer solstice at the Royal Museums Greenwich.

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Armillary sundial shadow one month on from winter solstice

Armillary sundial shadow one month on from winter solstice

The shadow of the ball on the sundial follows the sun all year round. The sun is low in the sky in winter, and it reaches its lowest point at the Winter Solstice on 21st December. This photo is one month later on 20th January. The sun is already higher in the sky, and the ball’s shadow has moved down.

Sundials catch a shadow from the sun. It is such a simple idea. The shadow on the sundial shows the sun’s position in the sky and the sundial reads it out as time, usually the time of day and often the time of year as well. Our armillary sundial is a special one with two balls that give the time of the year measured by the height of their shadow at noon. One ball casts a shadow in the winter months and the other one in summer. Continue reading

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Accurate Solar Time Sundial Installed in a North London Garden

Accurate Solar Time sundial installed and set up at the exact time of local Noon

The sundial is in our client’s garden in North London. The sundial faces due south. We set it up at Noon on 28 November, using accurate corrections for the Equation of Time and local Longitude. The photo shows Solar Time at 12.30pm.

The world of solar time has fascinating ideas to explore. Our accurate sundial is almost a compendium of what a sundial can do. The client’s wish was something special for their newly created garden, and our design of a vertical sundial display appealed to them. Continue reading

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An armillary sundial in early morning

An armillary sundial in early morning

This is our new sundial design. It stands in our garden among the plants. It is early morning and the sun has just reached the centre band where you read the time.

An armillary sundial has a wonderful form. It has mathematical rings creating beautiful shapes with circles and lines. The sundial in the photo has just begun to catch the early morning sun in the garden.

The sundial gnomon is the slanting rod in the centre of the rings, and the wide sweeping band is where you can read the time. These features are the same as other armillaries, but our design has special secrets. Continue reading

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New sundial installed in Lews Castle garden at Stornoway

New sundial installed at Lews Castle, Stornoway

New sundial installed on an original cast iron pedestal in the sunken garden at Lews Castle, Stornoway

The new sundial for Lews Castle at Stornoway is now in place in the sunken garden. The old cast iron pedestal has been restored and painted beautifully and the sundial fits perfectly on top. The local team at I M Murray Engineering carried out the work on site.

The handsome pedestal was once the base for a fountain. Continue reading

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Time lapse study of shadows and how a sundial reads the time

Time lapse on precision of a sundial

Time lapse camera set up for study of a sundial looking at precision of the time shadow

There are many interpretations of how well a sundial reads the time. It is often thought the smallest increment of time on a sundial will be around two minutes. This is because the large diameter of the sun gives a fuzzy edge to the time shadow. Our study looked at the shadow Continue reading

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