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The new sundial at St. Mary's Ashby

dedicated on a rather grey day in March 1999
.


Sundials and churches

The most ancient form of sundial on churches are the "mass dials". These are small circles incised in the stone, usually next to the church door, and were used to set a time for the church services. They were common up to about the 14th century. Those that remain are now very eroded.

More accurate sundials came into use after that. When mechanical clocks started to be used on churches, they were not very accurate, and would often gain or lose many minutes a day. The only way of resetting them (since there were no radio time signals then) was to use a sundial. When the sun next came out, the clock could be reset accurately.

At that time, every community kept its own local time. Noon was when the sun was at its highest (directly over the meridian). When the railways came, that all changed, because trains had to run on the same time wherever they were. And the telegraph meant that accurate time signals could be passed from one place to another. So the popularity of sundials gradually waned through the 1800s.

Lately, there has been a revival of interest in sundials. The British Sundial Society was founded ten years ago, and now has 600 members. It has done valuable work in the conservation of old sundials, and in encouraging high standards for new ones. And there have been many striking public sundials created in the last 10 years. One of the most well known is the four sided sundial placed on the tower of St. Margaret’s, Westminster in Parliament Square in London. This has a conventional south facing dial, which tells the time from 6 in the morning to 6 at night, and also east, west and north facing dials. The north facing one only tells the time from six at night to six in the morning, and so is only operational in summer!

Sundials come in all shapes, sizes, and materials; many of them, like this one at Ashby, are of stone with a metal gnomon. Among the sundials in the locality are the sundial over the porch at Blundeston Church*, and on churches at Badingham, Boxford, Bury St Edmonds cathedral, Clare, Copdock*, East Bergholt, Framlingham, Frostenden, Grundisburgh, Gt. Blakenham, Halesworth, Hawstead*, Heveningham, Horseheath, Kedington, Little Saxham, Little Thurlow, Oakley, Pakefield, Saxmundham Sproughton, Stansfield, Stoke by Clare, Stowmarket, Sudbury, Thorington, and Ufford. There is also a very fine and large one on the Moot Hall at Aldeburgh, and 3 others in the town. (The * ones are this century; most of the others are older)

Reading the sundial

When the line of the shadow is exactly over the shaft of the arrow which forms the hour line, the sundial is reading the hour indicated. You can tell this time very precisely, because the gilding on the V-groove of the arrow shaft reflects quite strongly in sunlight, so you will see the reflection to the right of the shadow grow smaller and smaller, and then vanish, and a moment later, the gilding on the left hand side of the arrow shaft will begin to reflect, and grow larger and larger. The exact hour is when you can not see any reflection from the gilding on either side of the arrow.

The half hours are marked by the small gaps between the tips of adjoining arrowheads.

Why does the time on the sundial not always agree with my watch?

Sundials and watches measure two different things, both related to time, and both accurate in what they do.

Human beings measure time by the motion of the un. When the sun is at its maximum height, we call it midday (or noon). The time between two successive middays, we call a day. Sundials divide the day between two middays into 24 equal parts, called hours.

Watches work differently. They divided the year up into 365 x 24 = 8,760 exactly equal parts called hours. 24 of these equal hours are called a day. This is why we speak of "mean time", because the hours are a mean or average over the whole of the year. As an idea, mean time is a very good one (and particularly good for watchmakers). It only begins to cause difficulties when people think of it as the "absolutely right" time. It is right for us, but only because everybody else around us is using the same time, so we don't miss trains or appointments. But it is not absolutely right, because days are not exactly equal in length.

Because the earth’s orbit is not parallel to the equator, and because the earth is going on an elliptical path round the sun, it has to go faster at some parts of its orbit than at others. And this means that the days are of unequal length,. Some are longer than others. The longest ones are in early August, and get up to 15 seconds longer than 24 hours. And the shortest ones are around Christmas, and they are up to 30 seconds shorter than 24 hours.

Because adjacent days are of very similar lengths, these small differences have a cumulative effect. Fortunately, the differences are not great in summer, being less than 5 minutes from early April to mid-July. In the autumn, however, the sundial appears to be up to 16 minutes fast, and in February, the sundial appears to be up to 14 minutes slow. (The difference is called by an old-fashioned word - the equation of time - though it is not actually an equation, but only a table of differences) The table below shows the time which should be on your watch when the sundial shadow is on the '12' line on the 1st, 11th, and 21st of each month throughout the year. For other dates, you can make an estimate by interpolation.. (Note: when summertime is in operation, add one hour to the times below)
Day of the month	1st		11th		21st
                      h     m   s		h   m   s		h   m   s
January            12:03:12:		12:07:38:		12:11:08:
February          12:13:33:		12:14:19:		12:13:49:
March	            12:12:34:		12:10:18:		12:07:28:
April	            12:04:08:		12:01:16:		11:59:00:
May	            11:55:52:		11:56:20:		11:56:26:
June	            11:57:35:		11:59:21:		12:01:28:
July                  12:03:33:		12:05:16:		12:06:15:
August             12:06:16:		12:05:14:		12:03:16:
September	12:00:12:		11:57:57:		11:53:20:
October           11:49:57:		11:46:58:		11:44:48:
November	11:43:40:		11:44:00:		11:45:44:
December	11:48:49:		11:52:58:		11:57:47:

Time, of course, depends on your longitude. If you are in the east of Canada or the USA, your time will be 5 hours different to the time in England. This is because your longitude is 75 degrees west of ours. As the sun appears to travel at 15 degrees an hour, it takes 5 hours to get to the east coast of North America.

Equally, Bristol is 2 deg. 35 secs. west of Greenwich, and so noon there is a little over 10 minutes later than noon at Greenwich. And, here at Ashby, we are 1 deg. 40 secs east of Greenwich, so noon here is 6 minutes and 40 seconds earlier than it is at Greenwich.

Most sundials made nowadays, including this one at Ashby, allow for this. The hour lines are slightly rotated so that, when the shadow is exactly on the '12' line, it is noon, not here at Ashby, but at Greenwich.

To summarise, sundials and watches can live together quite happily so long as everyone remembers they are measuring different things. And when we look at our watches, and "Its 12 o'clock" we should remember that we are not talking about the time here where we are standing, but we are talking about the time at Greenwich. In fact, when summer time is in operation, we are talking about the time 15 degrees to the east, in, say, Prague. So we can take pride in our watches - for keeping exactly in step with everyone else's - and we can also take pride in our sundials - for telling us the time by the sun, exactly as it is - today.

The Design

In 1993, the British Sundial Society held a conference at Urchfont in Wiltshire, and Piers Nicholson decided to build a "mini-tower" about 8 feet high and 4 feet square on plan, with a painted sundial on all 4 faces. This was a kind of "apprentice test piece" to demonstrate the different requirements of sundials facing different points of the compass. For the south-facing dial, a design consisting of red arrows flying towards the sun was chosen. When the design of the Ashby sundial was first discussed between him and Harriet James, his was one of the possibilities considered, and the design was improved by her and worked up so it would be suitable for stone carving.

The Motto

The motto "Aim higher than the mark" is a distillation from a number of quotations relating to arrows. Among them are "He who aims at the moon may hit the top of a tree; he who aims at the top of a tree is unlikely to get off the ground" (Penguin Dictionary of Quotations), "Who shoots at the midday sun though he be sure he never hit the mark, yet as sure he shall shoot higher that who aims but at a bush (Sir Philip Sidney (Arcadia, 1590), "He shoots higher that threatens the moon than he that aims at a tree (George Herbert) and "If you would hit the mark, you must aim a little above it (Longfellow, Elegaic Verse, 1880). Better poetry, even though less relevant to this subject, is
O many a shaft at random sent
Finds mark the archer little meant
And many a word at random spoken
May soothe, or wound, a heart that’s broken

The Gnomon

The gnomon is the part of the sundial which casts the shadow. If the sundial is to tell the correct time, it has to be set so that it is pointing directly at the Celestial Pole. This necessitates measuring very precisely the direction the wall on which the sundial is mounted is facing. The support for the gnomon consists of the intertwined letters ‘p’ and ‘n’ being the initials of the donor.

The Artist

Harriet James developed an interest in sundials while working as a memorial mason and signwriter in Wiltshire. She is a member of the British Sundial Society and has been making new sundials and restoring and recording old ones since 1989. Her dials are carved in stone or moulded in fibreglass, and are decorated with paint and gold leaf. Recent commissions include a slate dial for the University of Birmingham. Some of her dials are illustrated on the Internet at www.sundials.co.uk/hjames.htm, and she can be contacted at 26 Staverton, North Trowbridge, Wiltshire, BA14 6PB. Her website is at www.sundials.co.uk/hjames.htm

The Donor

Piers Nicholson lived at the Nebb at Flixton for some years in the early 1960s, and has kept it as a second home ever since. He has always had a special affection for St Mary’s Ashby where two of his children were christened. He is a member of the Council of the British Sundial Society, and is also the webmaster for the leading Internet site concerned with sundials, known as "Sundials on the Internet" at www.sundials.co.uk

Acknowledgements

The following gave invaluable assistance and support in the Ashby sundial project:
Rev. Jonathan Riviere, Rector of the Somerleyton group of parishes
Mrs. E. Halfacre of the Diocese of Norwich
Mrs. H. Dann and the Ashby Parochial Church Council
Trevor Betts and the staff of Foxwood Building Services, Norwich
John Davis of Flowton
M. Reeder of Blundeston

Their help is gratefully acknowledged


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    first posted March 1999 last revised 20 February 2004
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