These interactive ‘human’ sundials are suitable for public open spaces, parks and school playgrounds. To tell the time you stand on the marker for the current month with your back to the sun. Your own shadow points to the time on the ring of hours.
There are two numbers for each hour point – one for winter and one for summer when the clocks go forward for British Summer Time (red numbers for summer, blue for winter).
A well-drained, fairly level area is required, minimum 5m (east to west) and 4m (north to south) with no overshadowing from large trees or buildings, especially to the south. Dimensions of the ellipse are 4.3m (East-West) and 2.75m (North-South). The central date scale is 1200 x 600mm.
The sundials are made of sturdy moulded stone-coloured concrete pavers (30mm thick) and are designed to be set into grass on a concrete base. The central date scale consists of the names of each month and decorative symbols such as snowflakes for January and a hare for March. The moulded detail is painted with bright oil-based colours.
We offer a full layout and installation service or we can supply a sundial with instructions for DIY layout and installation (see prices below). If required, we can visit to assess the suitability of a site.
Sundials relate to many aspects of the National Curriculum particularly for Science: the seasons, day length and Earth’s tilt and rotation, the orbit of the earth round the sun, the apparent movement of the sun across the sky, the history of time-keeping, the heliocentric model of the universe etc.
Option 1: Complete sundial supplied and installed.
Price: £1100 including materials, labour and delivery (No VAT is payable).
The sundial is made of 17 hour pavers and 2 central pavers with concrete base. The pavers are fixed to the concrete base with hidden stainless steel ties.
Option 2: Sundial kit for DIY installation
Price: £675 including delivery (No VAT is payable)
17 hour pavers and 2 central pavers, stainless steel ties and epoxy glue.
For the DIY kit you will be supplied with full instructions for laying out a central north-south meridian line about which the sundial is built. You will need to cut out the grass, fix the stainless steel ties provided and supply and lay your own concrete base.
Etched metal or hand-carved plaques for dedications, commemorations etc. can be supplied and installed beside the sundial. Prices depend on size and number of words, so please supply the text if asking for a quotation.
Technical - Please read this before ordering:
Sundial time and Clock Time
Sundial (solar) time is not always the same as clock time (Greenwich Mean Time). Depending on the location and the date, there may be a difference of a few minutes between sundial time and clock time.
The Earth orbits the sun in an ellipse and has a tilt on its axis which causes a variation in the length of the day however Greenwich Mean Time works on a day made up of 24 hours of equal length. The difference between the solar time and mean time is known as The Equation of Time and has a different value each day.
The longitude of a sundial from the Greenwich meridian causes a further difference between solar time and mean time. The sun takes four minutes to traverse one degree of longitude from East to West, so for every degree west of Greenwich a sundial is four minutes slow and for every degree east of Greenwich a sundial is four minutes fast.
Your playground sundial will be supplied with an explanation of the differences between solar time and mean time. This will include a graph showing how many minutes to add or subtract to sundial time to find clock time depending on the date. The maximum differences between sundial time and clock time occur in February and November when there is least sun so most users will not notice the discrepancy between the two different times of time.
For further reading please see the British Sundial Society’s website: How Do Sundials Work
Before setting the sundial into the ground you will need to lay out a due north-south meridian line using the sun. This will need two people, a plumb line and some sunshine. We will give you the time at which the sun is due south at your location and at that moment you will need to mark the line of the plumb line shadow on the ground using spray paint or pegs and string. The line will form the centre line of the sundial.
The sundial should not be mowed over using heavy duty mowers with rollers as the paving stones could be cracked. It is best to strim round the sundial.
Accuracy of time-keeping
The sundials are designed for latitudes in Southern England i.e. around 51.5° North. Some minor errors in time-keeping will occur if the sundial is built further north.
Any queries, please contact me