time of year

A design of azimuth sundial to go in a garden

Azimuth sundial on 10 October at 11.10am

On 10 October the autumn equinox has passed and the cursor reading point has moved out from the inner circle of the dial towards winter solstice at the circumference. The sighting arm carries a short vertical gnomon which casts its shadow in line with the sun.

The azimuth sundial is an intriguing instrument. It finds the time from the direction of the sun. This idea sounds simple, the sun rises in the East, at Noon it is due South, and it sets again in the West, but it is complicated by the time of year. This note is about a new design for a precision azimuth sundial to go in a garden. Continue reading

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Armillary sundial on the day of autumn equinox at noon

Armillary sundial on the day of the autumn equinox at noon

Every day at noon the gnomon rod casts its shadow on the centre line of the meridian band. When the day of spring or autumn equinox arrives the two orb balls cast a double shadow onto the meridian band. Away from the equinox, only one orb shadow will show.

Our armillary sundial casts distinctive shadows at noon on the day of autumn equinox, as seen in the photo. Its unique design allows the noon shadow of the gnomon rod to fall on the broad meridian band at its centre line. The two orb balls also cast their noon shadow onto the meridian band. Continue reading

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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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