shadow

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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The impossible Dihelion sundial photo

The impossible Dihelion sundial photo

We shot this impossible photo blind because there is no room to stand between the sundial and the house wall.

Dihelion is our well-known dual sundial design, which reads solar time and solar declination. It is impossible to take this photo in the normal way because the sundial is too close to the house, and there is nowhere to stand. So the photo was taken by holding the camera against the house and shooting blind. At a first attempt, the picture has turned out well. Continue reading

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New design of armillary sphere takes shape in Edinburgh

New design of armillary sphere taking shape

A new design of armillary sphere takes shape in Edinburgh, inspired by an original sundial from Northern Italy. The skilled blacksmith work is complete. This is a bespoke design with gold highlights still to be painted.

A new design of armillary sphere has been taking shape in Edinburgh. It is inspired by an original sundial from Northern Italy which has an attractive and distinctive form. The expert blacksmiths at Ratho Byres Forge have done an excellent job in working from our design. 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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