Sundial sunset at Culzean Castle

This sundial at Culzean Castle was almost on the correct time last week. My watch said 7.51pm BST and it said 6.52pm GMT. This is a very precise sundial, to the nearest 2 minutes. But of course, it might be precise but it is not always accurate. There is a fierce debate in UK science education about the definition of these terms.ACCURATE means correct and given the problems highlighted by the Dusseldorf correction graph, sundials are only accurate some of the time. PRECISE is often defined as "to more decimal places", though in the case of a scale like the sundial, the word RESOLUTION would now be used instead of PRECISION - how small the scale divisions are. There is a brilliant poster from the NPL exlaining precise and accurate http://www.npl.co.uk/educate-explore/posters/sport/accuracy