Sundials and sunshine

The gardens of the National Trust for Scotland are a horological goldmine. Sometimes you have to look carefully to see the historical timepieces; from the standing sundial at Drum Castle to the wall-mounted sundials on the thunder house at Pitmedden, there are sundials galore in Trust places.

Gardeners are usually too busy to look at the time at the peak of the summer solstice, as the gardens never stop growing. Plants love the sunlight and the long day length means that they will grow for almost 20 hours in a day. Around the time of the longest day of the year the roses start to flower and summer-flowering shrubs such as Philadelphus and Deutzia provide heady scents. You need to visit the gardens as often as possible so you don’t miss the fast changes of the developing displays!

You can also see amazing displays of late-flowering Rhododendron in Branklyn and Arduaine, as well as the first crop of vegetables growing well in gardens such as Culross, Kellie Castle and Holmwood. Maybe the team at Threave will be trying to grow the longest cucumber!

A sundial is a device that tells the time of day using sunlight. In its simplest form, a sundial consists of a flat plate (the dial) and a gnomon, which casts a shadow onto the dial. As the sun appears to move across the sky, the shadow aligns with different hour-lines marked on the dial to indicate the time of day. The time-telling edge of the gnomon is called a style, although a single point or nodus may be used. The gnomon casts a broad shadow; the shadow of the style shows the time. The gnomon may be a rod, wire or elaborately decorated metal casting. The style must be parallel to the axis of the Earth’s rotation for the sundial to be accurate throughout the year. The style’s angle from horizontal is equal to the sundial’s geographical latitude.

In a broader sense, a sundial can be any device that uses the sun’s altitude or azimuth (or both) to show the time. In addition to their time-telling function, sundials are valued as decorative objects in our gardens.

A rudimentary sundial can be easily constructed by placing a stick in the ground or a nail in a board, and placing markers at the edge of a shadow or outlining a shadow at intervals. It’s common for inexpensive, mass-produced decorative sundials to have incorrectly aligned gnomons, shadow lengths and hour-lines, which cannot be adjusted to tell the correct time.

The earliest sundials known from the archaeological record are shadow clocks (1500BC) from ancient Egyptian and Babylonian astronomy. Presumably, humans were telling the time from shadow-lengths at an even earlier date, but this is hard to verify.

You can visit the site of possibly the oldest timepiece in history, found at Crathes Castle! The Warren Field is the location of a Mesolithic calendar monument built about 8,000 BCE. It includes 12 pits believed to correlate with phases of the moon and used as a lunar calendar. It’s considered to be the oldest lunar calendar yet found. It was originally discovered from the air as an anomaly in the terrain by the Royal Commission on the Ancient and Historical Monuments of Scotland, and was first excavated in 2004.

The pits align on the south-east horizon and with the Sluicht (now known as the Slug Road) associated with sunrise on the midwinter solstice. If proven, this Aberdeenshire time reckoner predates the Mesopotamian calendars by nearly 5,000 years. It has also been interpreted as a seasonal calendar because the local prehistoric communities, which relied on hunting migrating animals, needed to note the seasons so they could prepare for a particular food source. The Warren Field site is particularly significant for its very early date and the fact that it was created by hunter gatherer peoples, rather than sedentary farmers usually associated with monument building.

Our gardeners are always happy to share their expertise too. If you’re interested in gardening, make time to visit us and you won’t be disappointed. If you get lucky with the weather, you might even see our sundials in action!