Flamsteed Astronomy Society

Huygens, Halley & Harrison

— Anniversaries 2006

page 1 of 6

by Mike Dryland

Christiaan Huygens

The brilliant Dutch polymath, Christiaan Huygens, contributes two anniversaries :

1656 : (actually winter 1655/6) 350 years ago, he was the first to recognise Saturn’s rings for what they are — the planet was ‘surrounded by a thin flat ring which does not touch him anywhere’.  Galileo Galilei had been first to observe the phenomenon but didn’t correctly identify it.  He thought Saturn was a triple planet, and later became confused because the ring system disappeared from view as Saturn turned sideways-on to Earth.   Galileo wondered if Saturn had devoured his children as in the myth.   Huygens published his observations and explanation of Saturn in his book Systema Saturnium in 1659.  It still contains one of the best graphics explaining why the rings change appearance as they do seen from Earth.  Huygens was also the first to observe Saturn’s moon Titan, which is why the present mission is called Cassini-Huygens.

1656 :  Christmas Eve allegedly, although surely he had other things to do on Christmas Eve?  Huygens receives the first ‘prototype’ of his invention, the pendulum clock.  The pendulum was the first truly accurate ‘oscillator’ or regulator of clocks, and transformed timekeeping. It enabled a revolution in astronomy as observations of the movements of the heavens could now be made with high levels of precision.  Just 20 years later, the first Astronomer Royal at Greenwich, John Flamsteed, was installing the Tompion ‘Great Clocks’ in the Octagon room.  You can still see one of them there today.  Regulated by a pendulum 4 meters long, Flamsteed began by using them to verify the equation of time more precisely than ever before, and depended on them for his life’s work: the first accurate star catalogue of the northern hemisphere, and the first good enough as a basis for navigation.

With his invention of the pendulum clock, Huygens again seems to be standing on Galileo’s shoulders.  Galileo had been first to discover the equal-time swings of the pendulum apparently by watching a chandelier swinging in church.  He wrote about the application of a pendulum to a clock, but didn’t actually build one, although his son, Vincenzo, may have done so later.

Huygens gave his designs to the Dutch clockmaker Salomon Coster, for construction and Coster patented the idea in 1657.  The English clockmaker Ahaseurus Fromanteel, sent his son John to study with Coster in Holland.  In 1658 Fromanteel was the first to advertise pendulum clocks for sale in London.

Huygens went on to more ground-breaking developments in clockmaking.  He described the mathematics of ‘cycloidal cheeks’ which correct the tendency of a pendulum to change its ‘period’ (time of swing) for bigger arcs (amplitudes) of swing.   He also developed a clock controlled by a balance spring which brought him into contention with Robert Hooke over who had priority for this invention.   Huygens was a pioneer of the use of a clock to find the longitude at sea.  He built a couple of sea clocks which were tested on ships but didn’t perform sufficiently well.



How to pronounce ‘Huygens’


Click here for the answer from Harvard



Reconstruction of Huygens’ 1656 clock

(Science & Society Picture Library)

Christiaan Huygens

Christiaan was the son of diplomat Constantijn Huygens van Zulichem, an early patron of the artist Rembrandt

As 2006 draws to a close, here’s some history to chew on with the festive turkey.  During 2006 we’ve seen (or will see) at least seven anniversaries very relevant to the Royal Observatory.  I’m sure there are other significant ’xxx6’ anniversaries, so apologies to all those forgotten, but here are the ones I can remember just now.  We start 350 years ago, with a brilliant and alliterative trio — Huygens, Halley, and Harrison :

Turn over for Halley