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3. A new view of the Universe V Fred Watson, AAO April 2005 A new view of the Universe V Fred Watson, AAO April 2005

4. James Gregory

5. Born Nov. 1638, Drumoak Manse (near Aberdeen) Aberdeen Fit like the day? James Gregory

6. Around 1653, James entered Marischal College, Aberdeen Founded 1593, rebuilt c.1750 Education… United with King’s College in 1860…

7. James Gregory While at Aberdeen… James studied the science of optics and new ways of making telescopes: ‘Moved by a certain youthful ardour… I have girded myself with these optical speculations, chief among which is the demonstration of the telescope.’ (preface to Optica Promota, 1663)

8. London, c. Nov 1662–Feb 1663… James travelled to London to oversee the publication of Optica Promota. He made a brave attempt to build the first reflecting (mirror) telescope—of which more later. But he was anxious to be off to Paris to meet the great Dutch mathematician, Christiaan Huygens, and left it unfinished. James Gregory

9. Italy, c. May 1663–May 1668… James missed Huygens in Paris and had to be content to leave a copy of Optica Promota for him. He then went on to his main destination, the University of Padua. James Gregory

10. Padua… James Gregory

11. While in Padua… James Gregory James studied under the Professor of Mathematics, Stefano degli Angeli (himself a former pupil of Torricelli and Cavalieri) until May 1667. His own mathematical studies took on a new and original dimension, and he independently laid the foundations of the calculus (which is usually attributed to Newton and Leibniz). He published two books of great brilliance: Vera circuli (1667) and Geometriae pars universalis (1668).

12. James Gregory Back to London… Gregory returned to London in May 1668 to find that Vera circuli had been well-received. He was fêted by the scientific community because of his up-to- date knowledge of Italian science. James was elected a Fellow of the Royal Society on 11 June 1668. Gosh, it was nothing, really

13. James Gregory Royal intervention…? King Charles II seems to have been persuaded by James’ fellow countryman (and fellow member of the Royal Society), Sir Robert Moray, to found the Regius Chair of Mathematics at the University of St. Andrews.

14. James Gregory Off to St Andrews… James arrived at St. Andrews late in 1668.

15. James Gregory Gregory at St. Andrews… James in the Upper Library with his clock (by Joseph Knibb, 1673.)

16. Observing the stars… James Gregory

17. Gregory and the diffraction grating… James was intrigued by the behaviour of light as it passed through the feather of a sea-bird. He had demonstrated the first diffraction grating.

18. James Gregory BUT… In this, as in all his work, James deferred to his younger contemporary, Isaac Newton (1642--1727). I would gladly hear Mr Newton’s thoughts of it. And that was his main problem.

19. James Gregory Attitudes at St. Andrews… James was disappointed with the support he received at St. Andrews: ‘I am often troubled with great impertinences…’ ‘I was ashamed to answer, the affairs of the Observatory of St. Andrews were in such a bad condition, the reason of which was, a prejudice the masters of the University did take at the mathematics…’ So he left.

20. James Gregory …And, in 1674, went to Edinburgh In October 1675, James was observing the moons of Jupiter with his students. He suffered a stroke, and went blind. A few days later, he died. He was 36.

21. James Gregory A modern assessment of Gregory… He was ‘…the only one of Newton’s contemporaries who could match him in mathematical breadth and profundity’. But … ‘For all his talent and promise of future achievement, Gregory did not live long enough to make the major discovery that would have gained him popular fame.’ (D.T. Whiteside, 1969.)

22. James Gregory

23. The origins of the telescope…

24. James Gregory Lens telescopes in the 1660s…

25. There had to be a better way… In contrast, mirror telescopes developed entirely in the heads of the mathematicians of the day. Most notable were Réné Descartes (1596-- 1650) and Marin Mersenne (1588--1648) James Gregory

26. Gregory suggested combining mirrors and lenses… The problem was that no-one could make a mirror good enough for a telescope. James Gregory The reason why is due to basic optics…

27. Niccoló Zucchi had attempted to make a reflecting telescope back in 1616 It didn’t work.

28. Why not…? It’s 6 times harder to make an accurate mirror surface than a lens surface. (Prove it with the bathtub test…) Air Glass

29. In 1668, Newton won the day… Despite Gregory’s efforts in 1662 with the optician Richard Reeve, he didn’t quite make his telescope work. James Gregory Gregory had thought it ‘not worth the pains to trouble myself anie further with it’, and headed off to Paris.

30. But eventually, Gregory prevailed… Appropriately, it was the Edinburgh optician, James Short (1710-- 1768) who eventually perfected the Gregorian telescope. James Gregory And, in passing, made his fortune.

31. And, of course, the rest is history…