dial

Restoration of Inverkeithing Mercat Cross, finding true North

The azimuth sundial instrument

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. Continue reading

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Butterton church sundial and memorial brass from Tideswell

Butterton Church sundial restored

The Butterton church sundial has a new brass gnomon on the old dial plate. After many years outdoors the brass plate has turned green in colour. The Gothic script on the back of the plate shows it came from the Pursglove memorial in Tideswell church.

A few years ago we restored the sundial at St Bartholomew’s Church in the lovely Staffordshire village of Butterton. We found that the brass dial plate had ancient engraving in Gothic script on the underside, which was a mystery. The writing looked like part of a memorial brass, and we now know it came from Tideswell church in Derbyshire. Continue reading

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Sundial stones found in a Scottish garden — the cruciform stone

Cruciform sundial stone

The cruciform stone has four concave sides leaving four curving arms between them, thus creating the cross shape. This particular stone has a small concave end on each curving arm [not visible in the photo]. So the single stone has eight dials, on four large concave sides and four small ones. [Note: the shadow in this photo is from indoor lighting not from the sun.]

The cruciform type of sundial stone is a clever idea. During the day, as the sun moves round, each of the dials in turn will show a shadow and indicate the time. The straight dial edges cast the shadows. A cruciform stone can be on a lectern sundial but this one appears unique. Continue reading

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Sundial stones discovered in a Scottish garden — the stone globe

Globe terminator stone sundial

The globe sundial will show light and dark sides of the stone in sunshine. The terminator line separates the two and the hour numbers show the time.

This stone globe was initially puzzling. It has a band of hour numerals and looks like a type of sundial. It is actually a globe terminator dial. The hour band lies parallel to earth’s equator, and the line between light and dark shadow in sunshine is the terminator. The puzzle was why the globe had a second sundial  stone fixed onto it, since removed in the workshop, as a later post will explain. Continue reading

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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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A modern altitude sundial after Erasmus Habermel

A modern circular altitude sundial after Erasmus Habermel of Prague

Modern reconstruction of a 16th century altitude sundial for studying its mathematics and accuracy. An altitude dial uses the height of the sun to find the time. The dial is double-sided with the two half-years back-to-back.

Erasmus Habermel was a renowned scientific instrument maker working in the court of Emperor Rudolf II in Prague in the 16th century. He made instruments for all disciplines including astronomy and navigation. One of his sundials is an altitude dial in the clocks collection of the Augustine Museum in Freiburg im Bresgau*. It is an elegant circular dial and the mathematical construction is intriguing. Continue reading

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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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North alignment on a Victorian pedestal

Sun direction measured with an angle finder

The direction of the sun measured against one edge of the octagonal stone pedestal using the angle finder and light slit

A Victorian sundial pedestal stands in the gardens of Riccarton estate outside Edinburgh. It once held a beautiful octagonal dial which is now in safe storage. A replacement dial is to go on show and it must be in a correct orientation. The gnomon on a sundial must point north. A wrong alignment will make the sundial inaccurate, and nothing on the 19th century pedestal actually marks the north. Continue reading

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Historic Scottish Stone Sundial Restored

Scottish stone sundial restored

The octagonal base and baluster shaft support a carved cube stone. Before restoration the stones were covered in moss lying on the ground in the owner’s garden. The bronze horizontal dial is new.

Stone sundials were common in Scotland in the 17th and 18th centuries. They stood in the gardens of great houses, and in public places. The geometric form of the sundial would reflect the popular interests of the day in science and mathematics, and many displayed complex multiple dials. Originally this particular sundial may have belonged to a country estate near Falkirk. The present owner has had it for many years and in 2023 decided to restore it. Continue reading

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