Time

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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Watch Scotland’s tallest sundial on TV with Susan Calman

Secret Scotland with Susan Calman at Glamis Castle sundial

Susan Calman chats with Alastair Hunter about the grand sundial at Glamis Castle and finds out how to read the time.

Susan Calman loves her tours of Scotland uncovering secrets for her Channel 5 TV series, ‘Secret Scotland with Susan Calman’. This time she was in Aberdeenshire and Angus. She began with a visit to Glamis Castle, the much-loved family home of Her Majesty the Queen Mother. Susan could not miss the chance to see Scotland’s tallest sundial while she was there, Continue reading

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Summer solstice and a silver sundial

Dihelion dual sundial in silver

Silver Dihelion dual sundial sculpture able to read solstice and equinox, summer, winter, spring and autumn seasons, and the daytime hours.

Summer Solstice 2020 in Edinburgh was a day of beautiful sunshine. What could be a better time to show off our Dihelion dual sundial, which can read the solstice and the equinox seasons and the daytime hours. Shifting patterns of sunlight and shadow and petals of the sunflower show through so clearly. There is a lovely Continue reading

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Restoration of the obelisk sundial at Drummond Castle gardens

THE DRUMMOND CASTLE OBELISK SUNDIAL

The sundial consists of 61 multiple dials on raised panels and in sunken hollows. The date of the sundial is 1630. It has been made as an exhibition piece to show all of the sundial mathematics of its era.

The sundial obelisk at Drummond Castle in Perthshire has a long and distinguished history. It has its place in the architecture of the ancient castles and houses in Scotland. It is connected with the very earliest days of the British Sundial Society (BSS). And it is one of the most important free-standing sundials in the British Isles from the early 1600s still surviving.

In 2017 after almost four hundred years outdoors the sundial was showing serious signs of the stone deteriorating. The whole structure was feared to be unsound. Making it safe had become urgent. Continue reading

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Restoration of a multi-faceted Scottish stone sundial

Sundial restoration in Scotland

Multi-faceted stone sundial after restoration. There are 34 separate dials, two for local time and the others for different places round the world.

Restoration of ancient stone sundials in Scotland can be very successful. As a latest example, a multi-faceted sundial at Nunraw, East Lothian, was found in poor condition in the garden of a private estate where it stands. It has now been restored to full working order and looks spectacular. The restoration was completed in June 2019.

This sundial belongs to the great era of Scottish sundials in the 17th and 18th centuries. It consists of three multi-faceted stones with a total of 34 separate dials. Continue reading

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When is the shortest day when days get longer?

Graph of solar parameters

Graph of three solar parameters that affect the time of sunrise and hence the shortest day in the northern hemisphere. Latitude is a fourth parameter.

Summer has come and days are warmer—holidays are round the corner—but longer days are here no longer… Well, it is past summer solstice already! It is true the days are shortening now in the northern hemisphere. But when will the days get longer again? This is a technical puzzle. Like everything solar and astronomical there is no easy answer to the question.

Each year in December the media speak about the shortest day and then go on to say the mornings will still get darker. They are correct but how can this be? I thought I ought to clarify the question for myself if I could. It probably will not relieve anyone’s confusion by starting with a graph, so I have put my own study of the shortest day into an article for The British Sundial Society.

It has turned out a longer read than I expected—A study of the shortest day, Alastair Hunter. BSS Bulletin Volume 31(ii) June 2019

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Drummond Castle Sundial Restoration

Drummond Castle Sundial Obelisk

The sundial dates from 1630. It has 61 individual dials and 131 separate ways of telling the time. An inscription in Latin carved into the stone explains the separate colours chosen for time. The lines remain but the colours have gone.

The sundial at Drummond Castle in Perthshire is the earliest of the distinctive style of sundials in Scotland. It dates from 1630. Three years ago it was removed from the garden for major repairs and conservation work. This restoration is now complete and the sundial stands tall in its glory again.

A sundial reinstatement ceremony was held on Sunday 23rd June 2019 at 11.00 am. Continue reading

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Babylonian and Italian hours measure the day

Babylonian and Italian hours on a sundial

This vertical dial has hour lines radiating from the top, as well as the criss-cross pattern of Babylonian and Italian hour lines, plus the lines for solstice and equinox. Looking at the shadow of the gnomon, the time of day is 9:30 am and the time of year is the equinox. The Babylonian time is 3½ hours from sunrise, and the Italian time is 8½ hours before sunset. Adding these together the length of day for the equinox is 12 hours.—Note, the figure has no numbers. Once you learn how to read the lines, it is not hard to learn how to count them!

Babylonian and Italian hours are wonderful. They measure out the day from the time of sunrise to the time of sunset. Add them together and they will give you the number of hours of daylight. A simple ancient type of sundial like this one can measure times for you that you will hardly ever find on a modern watch. Continue reading

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Oak leaf sundial art

Oak leaf sundial

This beautiful sculpture projects the shadow of oak leaves etched in glass onto the carved sundial panel behind. The shadow of a single oak bud falls in exactly the right place to tell the time.

There is so much pleasure in owning a work of art done by a friend. For a sundial person the pleasure is even greater when this is a sculpture that can show the time. Today we set the sculpture up at home and we were amazed how beautifully it comes to life in sunshine. All the fundamentals of a sundial underlie this marvellous creation. Continue reading

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