John Dee and the Invention of the Telescope



26th October 2010
Was the first telescope made around 1607 as is commonly supposed - or did the English scholar John Dee (1527-1609) play a part in its invention many years earlier? I am not an historian or a scientist. I am a writer of fiction. But I have studied the life and times of Dee a little. And I suspect that he should, at the very least, be given some credit in this respect and that he might well have played a part in the evolution of possibly the most important scientific instrument of the Renaissance. The evidence that I am aware of is presented here. You decide.
antique marine telescope - extendable
An early marine telescope.

Telescope - background



The conventional wisdom is that the telescope was invented in Holland around the beginning of the 17th century and probably by one Hans Lippershey (c1570-c1619). Its existence was first recorded with some certainty by 1607. The Italian astronomer Galileo is then thought to have obtained one shortly after. And it was in 1609 that he began observing the Moon, stars and planets in close-up - thereby setting off somewhat of a revolution in our understanding of the heavens. His ground-breaking work, famously, put him at loggerheads with the Church and its teachings at the time.

But where did the Dutch telescope come from? Was there a forerunner to it?

Lenses

It is worth remembering that glass lenses had been in wide circulation for many centuries by Dee's time. Corrective lenses for reading were certainly in use by 14th century as the painting shown below demonstrates.
detail from painting showing medieval gentleman in spectacles, reading
Detail of a portrait of Hugh de Provence, painted by Tomaso da Modena in 1352.
When we consider that a rudimentary telescope is little more than the placement of two lenses in line to one another at a distance of several inches, it seems unlikely that scholars of optics such as Dee would not have been aware of the magnification phenomenon regarding distant objects.

Introducing John Dee



On the stage of history there is perhaps no character more misunderstood or maligned than John Dee, the English mathematician, geographer and astrologer to Queen Elizabeth I. In his day he was described as 'the most learned man in Europe' - 'the Ornament of his Age.' Yet by the middle of the 17th Century Dee was already labeled as a fantasist and a hellhound. In our own times he has been virtually wiped from the pages of history. Many of his achievements have been forgotten, overlooked or else deliberately ignored.

The reasons for this dreadful state cannot be addressed in this brief article. His neglect has possibly much to do with his reputation as a man who believed in the existence of spirits and angels. And in our present ultra-rational times he has never gone down well with the intellectual establishment. This oversight is being removed gradually, however. A recent conference (2009) at St.Johns College, Cambridge (Dee's own College) was attended by scholars from around the world in a bid to discuss and re-evaluate his life and work. Certainly a step in the right direction.
engraving of Tudor man in scholar's cap, white beard
19th century engraving of John Dee.

The Evidence



Here are a number of quotes below from historical sources. Some of these are from Dee's friend and colleague Thomas Digges, others by William Bourne, both prominent mathematicians of the times. There is also a quote from Dee himself. Students of optics will perceive that some of these might well be describing the layout and construction of a reflecting telescope (an even later 'invention') as well as the original refractor.
antique reflecting telescope on mount, wooden tube
An early form of reflecting telescope.
One important point to bear in mind. The term 'telescope' did not come into being until the 17th century. Prior to that it was called a 'perspective glass' or a 'spyglass.' If the 'perspective glass' was ever made at this time, it would probably have been a closely guarded secret for military and navel purposes. In this context we do know that Dee lobbied at Court for a coastguard service for England's defence. And he urged that perspective glasses be installed in all of her Majesty's ships.

Thomas Digges


Thomas Digges (1546-1595), by the way, was a very close colleague of Dee's. His father, Leonard Digges, also an astronomer, entrusted the upbringing of his son to Dee who became his Guardian at an early age. The mathematical work of Dee and Thomas Digges proceeded in tandem for many years. And scholars have been able to isolate numerous similarities and shared ideas between the two men throughout their careers.

Quotes


Firstly, a quote from Dee in his preface to Billingsley's Euclid, 1570 where he proffers advice to military commanders for purposes of obtaining knowledge of enemy forces:

'He may wonderfully helpe him selfe, by Perspective Glasses, in which (I trust) our posterity will prove more skillfull and expert, and to greater purposes, than in these days …'

Next: extracts from a report on military and naval inventions, written by the mathematician William Bourne, for Lord Burghley, 1578:

"The effects of what may bee done with these last two sortes of Glasses: The one concave with a foyle ... and the other grounde and polished smoothe, the thickest in the myddle, and thinnest towards ye edges, or sydes.' ... there ys dyvers in this Lande, that can say and dothe knowe muche more, in these causes then I: and specially Mr Dee, and also Mr Thomas Digges.... Yet I am assured that the Glasse that ys grounde, beeynge of very cleare stuffe ... will shewe the thinge of marvelous largenes, in a manner uncredable to bee believed of the common people.'

Next: Thomas Digges in his revised edition of his father's book Pantometria' Date 1571:

'... my father by his continual pain-full practices [practical experiments], assisted with Demonstrations Mathematicall, was able and sundrie Times hath by proportionall Glasses duly situate in convenient angles, not onely discovered things farre off, read letters, numbered peeces of money with the very coyne and superscription thereof, cast by some of his freends of purpose uppon Downes in open fields, but also at seven miles declared what had been doon at that instant in private places.....'

Next: Thomas Digges in his 1576 addendum to his father's 'Prognostication Everlastinge' suggests that the stars are infinite in number - typical of the conclusions reached through using a telescope to reveal ever-more stars with each increase in magnification. Hitherto, the sphere of the fixed stars was thought to be finite in number - limited to what was visible to the eye.

Finally, it is worth remembering that John Dee's library (one of the most extensive in Europe at the time) held many ancient books and manuscripts. Included, was the work of the 13th Century mystic and scientist Roger Bacon and among which Leonard Digges discovered the following passage on lenses and the ability to use them to:
'.....cause the sun, moon and stars in appearance to descend here below....'
Bacon, Roger 'Opus Majus', ca 1267.

This spurred Digges' research into optics, which was passed on to his son.
drawings of moon in old book, early showing of detail
Galileo's drawings from his book 'Sidereus Nuncius' showing detail of the Moon.

Conclusion


Keeping in mind John Dee's life-long interest in the stars, it is unlikely that he would not have used his understanding of optics and perspective glasses to turn a rudimentary telescope to the heavens at some time during his long career as a scientist in Elizabethan England. The assertion in many of our history books that in 1609, the Italian astronomer Galileo was the first person to use a telescope to observe the moon, stars and planets is possibly inaccurate, therefore. It might well benefit from reappraisal at some time in the future. The year 1609, when Galileo's observations commenced, was coincidentally, the year in which John Dee died.
Authored by Robert Stephen Parry

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