Thomas Harriot, 1560 - 1621

Note: This page also contains information about the replica telescopes made for Telescope400.

A short biography of "England’s Galileo" by Allan Chapman.

While the telescope seems to have been invented in Holland in 1608, it is Galileo Galilei, in Venice and Padua in Italy who is generally accredited as having made the first telescopic discoveries towards the end of 1609. Indeed, Galileo’s Siderius Nuncius (“Starry Messenger”) published in spring 1610, had announced these telescopic discoveries, including the rugged surface of the Moon and the satellites of Jupiter, which began a quantum shift in mankind’s idea of the Universe.

One of Harriot's drawings
A new colour scan of one of Harriot's moon drawings done for this project

Yet it was an Englishman and a Welshman who were the first people in the world to examine the Moon through a telescope, and to record (though not to publish) what they saw. For on 26th July 1609, Thomas Harriot used his x6 magnification “Dutch Spyglass” to observe the Moon.

Then, on 6th February 1610, Sir William Lower of Traventi, Carmarthenshire, wrote to his friend Harriot likening his own telescopic views of the Moon “unto the description of coasts, in the dutch bookes of voyages. In the full she appears like a tarte that my cook made me last weeke. Here a vaine of bright stuffe, and there darke. I must confess I can see none of this without my cylinder” [Telescope].

On 3 December 1610, Harriot independently discovered spots on the Sun – which contradicted Aristotle’s classical view that the Sun was perfect and unblemished – while he also went on to draw the first plausibly accurate map of the lunar surface, monitor the motions of Jupiter’s moons (after Galileo’s prior announcement of their discovery), and to see more stars in the Pleiades than were visible to the naked eye.

Allan Chapman demonstrates his telescope replica [1]
A new colour scan of one of Harriot's moon drawings done for this project

Yet why are Thomas Harriot, and Sir William Lower largely forgotten? A lot has to do with their circumstances. In 1610, Galileo was a 46 year old Italian professor, struggling on a modest salary, and dearly wanting to be famous. Galileo was also a brilliant arguer and self publicist – traits which led to significantly to his brush with the Inquisition in 1632. Harriot, however, was a comfortably off bachelor, living at Sion House, near Richmond, in the entourage of the politically controversial Earl of Northumberland. And Lower was a landed country gentleman. Neither men seem to have been publicity seekers, like Galileo. Indeed, considering the political notoriety of his patron, Northumberland, Harriot preferred to keep his head down. On the other hand, Harriot, Lower and Galileo were all Copernicans, who held to the theory that the Earth rotates around the Sun, and all three men realised that their telescopic discoveries more easily fitted that theory than did the classical one that argued the Earth was the centre of the Universe. Indeed, Harriot, who was 49 in 1609, had moved amongst English Copernicans for most of his life, having been influenced as a young man by Thomas Digges, who had suggested in 1585 that the stars receded to infinity. And over 1585-86, he had been the “scientist” on board the first-ever British exhibition to study and survey Virginia in America. (Harriot’s astonishingly perceptive and sympathetic study of the culture, customs and religious beliefs of the local Algonkian Indians also qualifies him as Great Britain’s first anthropologist).

Harriot was born in Oxford in 1560, and while we know nothing about his parents or family, we do know that he went up to St Mary’s Hall, on Oxford’s High Street, facing the University Church of St Mary the Virgin, in 1577, and took his BA in 1580. St Mary’s Hall no longer exists, having been incorporated into its neighbour, Oriel College, in the late-Victorian period. After graduating, Harriot embarked on a scientific career. His earliest, and only published researches were in ethnology, anthropology, and travel literature as he was then part of the circle of Sir Walter Ralegh. But his lifelong passions were astronomy and pure mathematics. Harriot was one of the greatest mathematicians that Great Britain has ever produced, but it is his telescopic observations for which he is most famous today. Many of Harriot’s manuscripts, including his Moon drawings, still survive; many being in the British Library, London. It was not until 1832, however, that Stephen P. Rigaud published major extracts from these papers – including the astronomical observations – in his “Miscellaneous Works of …. Dr. James Bradley” (Oxford 1832). And during the 20th Century many historians of science have studied his manuscripts, and published major books and papers devoted to them. There is also a Thomas Harriot Seminar, which meets alternatively at Oxford and Durham Universities.

Dating back, perhaps to his youthful friendship with Sir Walter Ralegh, Thomas Harriot seems to have been a heavy pipe smoker. He died of a cancerous tumour inside his left nostril on 2nd July 1621, at the age of 61. So in addition to all his other distinctions, Thomas Harriot may have been one of the first Englishmen to die from a smoking-related cancer!

Dr Allan Chapman
Wadham College, Oxford.


About Harriot's Telescope and our replicas:

As part of Telescope400 the team arranged for two replica telescopes to be made by Mike Tabb in Bath. This additional section to Harriot's biography page has been added (March 2015) following requests for more information about this subject.

The round replica telescope, now at the South Down Planetarium
replica telescope


Mike Tabb describes the optics of the two instruments he constructed thus:

  • The square oak tube instrument has objective F = 800mm 38mm diam., stopped down to about 18mm. Eye lens f = -125mm 25mm diam., stopped down to about 11mm. power 6.4 (Now with Herschel Museum of Astronomy, Bath).
  • The round pasteboard instrument has objective F = 700mm 38mm diam., stopped down to about 18mm. Eye lens f = -125mm 25mm diam. stopped down to about 11mm. power 5.6  (Now with the South Downs Planetarium, Chichester).

After Telescope400, the replica telescopes were given to the Herschel Museum of Astronomy, Bath, and the South Downs Planetarium. If you would like to see the replicas, then please contact the relevant institution prior to visiting to ensure they are available.

The square oak replica
replica telescope

Robin Scagell writes: There is virtually no information actually available about Harriot's telescopes. The replicas are based on what we know about the way telescopes might have been constructed at the time, rather than being faithful copies of anything specific. Regarding the square tube, I think Mike Tabb found that someone had referred to his telescope as 'like his flute case' and it is well known that Harriot called it 'a Dutch Trunk'. These remarks could imply a square tube, and I think Mike had a chat with Allan Chapman about it and visited the Museum for the History of Science at Oxford. There is no other documentation about the appearance of the telescope, and when I spoke with Allan some time ago about it he suggested that we just go ahead and do something that looked right!

So while Allan has followed Galileo's circular tube (which Harriot would probably not have seen), Mike decided that there was some evidence for a square tube so made one of each. Mike consulted Allan on other details, and the lenses are held in place using leather washers which Allan says is likely to be the method. The only major non-authentic aspect is that the lenses are modern commercial ones and therefore maybe of better quality and smoother than Harriot's (though spectacle lens grinding was a well-established technology by then). Mike would have liked to have made his own, but didn't have the time. The Galilean telescope optics, which Harriot would have used, had an ordinary convex spectacle lens as the objective (at the top end of the tube) but had a negative lens for the eye lens. This gives a tiny field of view, but does give an upright image, unlike the later Keplerian telescope design which is in effect what we use today, with another convex lens for the eyepiece.

Lens making by his time was a practised art, as spectacles had been in use since the late 13th century, though probably only among the monied classes. The marbled paper that covers the round pasteboard tube is appropriate as a decoration -- they had that in those days, but of course this is a modern paper and not an attempt at a replica.

Moon through one of the replica telescopes
Moon through replica telescope

Mike found that it is important to blacken the inside of the tube to avoid stray reflections. As for the cradles, there is no information at all on how Harriot supported his telescopes. The rubber bands are an anachronism and perhaps we should have used catgut but that was a step too far.

When I viewed the full Moon through the telescopes I found that it almost exactly filled the field of view. There was very little false colour, but I found it surprisingly difficult to see really clear detail - see the adjacent photo I took through the telescope."



[1] Picture of Allan Chapman shows him holding a replica he made of a telescope of Harriot's era. This telescope is the one shown in January 2009 on the BBC "Sky at Night" programme. The picture was taken at the time of his talk about Harriot at Astrofest 2009.
More detailed article on Harriot: The February edition of A&G (News and Reviews in Astronomy and Geophysics) published an interesting and more detailed article on Harriot, also by Dr Allan Chapman. A copy is here
Listen to Allan talk about Harriot: Available in a podcast issued 14th January 2009 available here as part of the International Year of Astronomy initiative


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