Wednesday, 17 September 2014

Astronomy Scrapbook Wednesday 17th September 2014

September 17th 1764 the birth of John Goodricke.

John Goodricke 1764-1786, One of the Fathers of Variable Star Astronomy

This is the story of John Goodricke, one of the most talented astronomers of all time. Deaf from a very early age, he had a tragically short life but his contribution to astronomy was immense.

The Goodrickes were an English aristocratic family with an ancestral home, Ribston Hall, near Knaresborough in North Yorkshire. John was born in Groningen, Holland on September 17th, 1764 to Henry and Levina. Sadly, after an illness early in his life, the infant John was found to be deaf.

In the early 1770s John’s parents returned to England and settled in York. The young John was sent to Edinburgh to a school for deaf children run by Thomas Braidwood. We have little information about this part of his life; it is possible he learnt to lip read and probably to speak as well. Sign language had not yet been devised. In 1778 he was sent to the Warrington Academy, a famous Dissenting school which had no special provisions for children with disabilities.

It was at the Warrington Academy that he developed a great interest in mathematics, science and astronomy. After three years he left Warrington to live in the Treasurer’s House near York Minster, now in the keeping of The National Trust. It was here that his astronomical career was to begin. His astronomical journal started on November 16th 1781.

 A year earlier a distant cousin had also moved to York. Edward Pigott lived with his father Nathaniel in a house that survives to this day as No. 33 Bootham. Edward and his father were both astronomers.

Together John Goodricke and Edward Pigott forged a partnership that would push back the frontiers of astronomy.  Not only would they make discoveries but like true scientists they would try to explain them, and their five year partnership would make York one of the astronomical centres of the world.

The two astronomers came together in 1781, a few months after William Herschel discovered the planet Uranus from his home in the city of Bath. The scientific community was abuzz with all things astronomical. They must have seemed an odd couple; Goodricke, a deaf youth of just 17, and his older cousin Pigott who, having spent much of his life living in France, liked to dress in the flamboyant French style.
The Pigott’s observatory has been described as the third best private observatory in England, while Goodricke observed from a room in the Treasurer’s House using a small telescope.

Pigott and Goodricke knew of a star in the constellation of Perseus called Algol, or Beta Perseus. The constellation depicts Perseus holding the head of the Medusa.  Algol marks the eye of the Medusa. 

As far back as 1669 astronomers had noticed something odd about this star. It is what we refer to today as a variable star, because it varies in brightness. The world Algol means ‘The Winking Demon’.  Goodricke observed the star and recorded that it remained at its brightest for 2 days, 20 hours, 45 minutes, and then faded away for about 10 hours before recovering again to its normal brightness. Goodricke’s observations came very close to modern estimates, even though he had only his eyes and a clock to work with.  

As Goodricke couldn’t hear the clock ticking, a servant beat out the seconds with a finger so he could accurately work out the time. Goodricke was obsessed by precise timing. When he was observing Algol from the Treasurer’s House and Pigott was doing the same from his observatory in Bootham a few hundred metres away, he worked out that if they used the chimes of the bells in York Minster, they needed to allow for the extra time it took for the sound to reach Pigott.

Goodricke and Pigott correctly deduced that there was another body orbiting Algol, causing the light to vary. They believed that it could be a planet; we know today that it was another star. Today astronomers find planets around other stars using the principles put forward by Goodricke and Pigott. Their ideas were over two hundred years ahead of their time.

John Goodricke was only nineteen in 1783 when he wrote to the Royal Society about his observations and thoughts on Algol.  He was deaf and unknown outside of York, but Edward Pigott moved in the right circles and knew everyone of importance in astronomy. He contacted his friend the Astronomer Royal Nevil Maskelyne and soon Goodricke’s work was published.

The effect on the astronomical community was electrifying. All over the country people were observing Algol and Goodricke was awarded the Copley medal by the Royal Society, the highest award they could give.  

Goodricke and Pigott had made a remarkable contribution to variable star astronomy and this was just the start of their endeavours.

September 10th 1784 would become a night to remember in York, with not just one but two new variable stars being discovered. Goodricke found Beta Lyra in the constellation of Lyra (the Lyre), while Pigott was discovering Eta Aquila in the constellation of Aquila (the Eagle).

The indefatigable Goodricke was to discover another variable star, Delta Cepheus in the constellation of Cepheus (the King), on October 24th 1784. This star is of immense importance today as it is a prototype for the Cepheid type variables which are used to determine how far away galaxies are. Goodricke could never know of the importance of this star to astronomy.

More reports were sent to The Royal Society. Astronomers in London must have wondered what on earth was going on in York!

Goodricke’s short life was nearly over. He was made a fellow of the Royal Society; a most prestigious honour for someone so young, but never knew about his election because he died on April 20th 1786, two weeks before the letter arrived. He was only twenty one, and observing the night sky in the very cold conditions of the time probably contributed to his death from pneumonia.

Pigott moved to the city of Bath where he continued observing the night sky and in 1795 he discovered the variable stars R Corona Borealis and R Scutum. I have christened Goodricke and Pigott ‘The Fathers of Variable Star Astronomy’.


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