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The Actuary The magazine of the Institute & Faculty of Actuaries

Actuaries and their sundials

We were intrigued to notice that retired actuary Frederick W Sawyer III is the current holder of the onerous post of president of the North American Sundial Society. He contributed to a recent exposition on these oldest of timepieces in the Washington Post.

‘Everyone is fascinated when they see a sundial actually working’, said Mr Sawyer. ‘In the home garden, it would be nice for people to set them up so they actually work.’ First, the angle of the sundial’s slanting shadow-maker, which is called a gnomon, has to match the latitude it is in (approximately 39°N in Washington). The angles between the hour marks must also be arranged for one’s latitude.

Also, the noon mark on the dial must be orientated to true north. Even then, the sundial will not precisely match the clock. Every day, the sun reaches its high point in the sky, the moment known as the meridian, which occurs at a different moment at any location within a single county or state (because time zones depart from solar time).

Our very own sundial enthusiast Peter Tompkins told The Actuary that Frederick Sawyer is much better known in the world of sundials than in that of actuaries. Are there any other sundial enthusiast actuaries out there – we would love to feature you in a future issue!