The British Sundial Society
Promoting the Art and Science of Gnomonics since 1989
Castle Howard and Greenwich Observatory
Fully illustrated explanations
Projects to make your own dials
Frank King writes “You will, off course, instantly appreciate why I am sending Leap-Year-Day Greetings today, 24 February.”
Readers who need their memories refreshed are referred to the following extract from Frank’s article entitled “Mind the Gap…” in the December 2011 Bulletin.
When is Leap-Year Day?
Sometime after the Paternoster Square noon mark was completed, I received an unexpected e-mail suggesting that 29 February was the wrong date to choose for the thin strip and that the correct date of the intercalary day is 24 February. To quote from the message:
As far as I know nobody, at least in this country, has formally moved it from day 55 in the year (starting January 1st). In any case, who would have authority to do so?
This message could not be lightly dismissed. It was from John Chambers, former Head of the UK Time Service at the National Physical Laboratory, whose responsibilities included overseeing the broadcast of the Greenwich Time Signal. Some explanation is necessary!
In a break with previous ideas Alastair Hunter has created an original new sundial that has two shadows, one showing the time of day and another the season of the year. This can add more pleasure to having a sundial in a garden. The design was created in 2015 and has been named DIHELION meaning ‘dual sun’ after ancient Greek words. The sundial was shown to the public at ‘Sculpture in the Garden’, the annual sculpture exhibition at The Savill Garden, Egham, Surrey, which ran from 1 September to 31 October.
In sundial terms, DIHELION is the combination in a single piece of a horizontal dial and an altitude dial. The horizontal dial shows the hours. The altitude dial shows the passage of the year’s four seasons by measuring the solstice and equinox declinations. Each dial plate carries a gnomon that casts a shadow onto the other dial. The horizontal plate carries a gnomon for the altitude dial. The vertical plate carries a polar gnomon for the horizontal dial.
This reproduction (NOT a ‘replica’ which would include antique patination and the blemishes of age) began life in 2010 at a NASS Conference when an original plate made by Heath & Wing of London was shown to me with a request for a full-size copy re-delineated for its new home on Prince Edward Island in Canada. Lots of photographic studies were made, many including a mm rule for total accuracy. Over several weeks the artwork for the dial was created ‘from scratch’ by hand using Adobe illustrator. In particular, selected lettering from the engraving was traced at high magnification and sent to ‘Your Fonts’ who returned a TrueType font file to allow me to ‘key-in’ the inscriptions in authentic lettering. Every other artwork aspect is the direct product of my own hand frpm many hours of ‘mousing’.
PROFESSIONAL RESTORATION CLASS
Submitted by Charles Perry Restorations Ltd,
Praewood Farm, Hemel Hempstead Road, St Albans AL3 6AA
In 2010, Charles Perry Ltd was contacted to remove, restore and replace the elaborate vertical sundial at All Saints’ Church in Isleworth. The Church dates in part, back to 1398. The first sundial there is believed to have been a painted vertical wooden sundial which was dedicated to the memory of Susannah, fourth wife of Colonel Sir Nicholas Lawes (Chief Justice of Jamaica from 1698 to 1703 and Governor from 1718 to 1722) who had died in 1707 at the age of 47. Church records, such as they are, show that the sundial has been repainted and maintained ever since.
Sadly, the church, except for the tower, was destroyed in 1943 by two boys, who had set fire to five churches in the area in the course of a few days, destroying much of the fabric of All Saints’ and one other. After years of indecision the desire for a full restoration was finally abandoned on cost grounds and in 1970 a smaller modern brick building was openly linked to the remaining tower. It is this building that continues in use today and the then present sundial was mounted high (arguably somewhat too high) on the new Lady Chapel of this building.
In 1922, Professor Hugo Michnik, invented the bifilar sundial. In the original version, the bifilar sundial has two non-touching threads parallel to the horizontal dial. The second thread is orthogonal to the first. The intersection of the two threads’ shadows gives the local apparent time.
The sundial in its setting with some of the accompanying sculptural and landscaping work.
Visitor Interpretation Area
Ben Lawers National Nature Reserve
Longitude: 4.2º West
Latitude: 56.55º North
Client: National Trust for Scotland
Designed and made by Tim Chalk
Concrete casting by Gray Concrete
Commissioned January 2012
Completed June 2012
Dial Type: Free standing vertical Dial with angled solar calendar slab
Materials: Cast Glass Reinforced Concrete, Cor-ten Steel
Dimensions: 1.2 metres(h) x 800mm(w) x 100mm(d)