The early evolution of the telescope

by Philip Morrison

The American Philosophical Society revealed that Galileo was not one quick to rush into print. Eighteen years a professor in Padua, he had published only two books, one an instruction manual for a geometrical instrument he had invented and sold out of his own private workshop, the other a witty polemic against a Padovan student who had sought to rip off that very instruction book! But from the time Galileo first heard of the spyglass of "a certain Fleming" until his book The Starry Messenger opened the Copernican universe to our extended senses, just 10 months elapsed. He was onto a good thing and he published it first, in March of 1610.

There were probably three men who had telescopes by early in October of 1608. At the autumn fair in Frankfurt that year a Dutchman was offering one for a high price. And it was not a novel idea to look through such an instrument at the stars. The first printed account from the Hague mentions that the glass showed new stars in the Pleiades, months before any telescope came to Paris, Milan, Venice or Naples. But Galileo worked hard and well, he had the help of a master craftsman in his own shop, he had access to selected lots of the best Venice glass, he ground scores of lenses and chose the best of them, he grasped the importance of a steady mount and he invented an aperture stop to correct the faults of his high-powered lenses. There is no doubt that his was a magnificent and purposeful development, even though it was not an invention; he described the new cosmos, beating out Thomas Harriot, Simon Marius, Christoph Scheiner and the wonderful Paris amateur Nicolas de Peirese, all of whom were gazing at the sky through telescopes at about the same time.

Check your comprehension

~ Did Galileo have a lot of publications?

~ Was Galileo the first man to look through a telescope at the stars?

Professor Van Helden’s fascinating and learned little monograph The Invention of the Telescope includes Galileo; it focuses, however, not on him but on the “certain Fleming,” whoever he was. We see the main evidence in this long detective story: 30-odd key passages from books, letters, journals and official documents, in the original Latin, English, Italian, French and Dutch, all with clear translations. The documents begin with Roger Racon, who wrote in about 1250 of “Glasses so cast, that...starres shine in what place you please.” They end with a long passage of 1655 from a book seeking “the true inventor of the telescope” and finding him in an artisan of Middelburg in Zeeland.

One reads the 1609 letter of Giovan-baptista della Porta himself, who says of the new Dutch wonder: “I have seen it, and it is a hoax, and it is taken from the ninth book of my De refractione.” Nevertheless, the noble Girolamo Sirtori pursued the glass over ail Europe, seeking experts who could grind usable lenses. He examined and measured Galileo’s own tube and lenses at that famous dinner of the Academy of Lynxes in Rome where the word “telescope” was coined in the spring of 1611, yet he was not able to duplicate the success of the Tuscan artist.

There is a famous journal entry that cites a statement (against self interest) made by the son of Sacharias Janssen, the strongest candidate for the designation of inventor, suggesting that the father (an unsavory character, convicted counterfeiter) “made the first telescope in this country in the year 1604, after one belonging to an Italian which bore the date anno 190.” (Stillman Drake thinks the error was for 1590; since the text clearly intends a date, 1590 is hard to fault.) Another claimant is a Florentine. Raffael Gualterotti, who wrote Galileo in April 1610, asserting that he, and no Dutchman, was the inventor: “It is now twelve years since I made an instrument ... for the benefit of a cavalry soldier … A feeble thing.”

Check your comprehension

~ What does the author refer to as ‘long detective story’? What is the main evidence in it?

~ When and where did the word “telescope” first appear?

How can all this be true? How can the telescope have become the cynosure of Europe in a year or two after 1608 and yet have remained unknown for a decade or more before that? Professor Van Helden, a historian at Rice University, offers a persuasive explanation. The erect-image two-lens instrument was indeed not very new. It had been found quite naturally during the 1590’s by combining the then common lenses of the spectacle makers. It was of some help to myopics, but its lower power and poor lenses made it a thing of no great virtue. The early optical experimenters, on the other hand, were hoping for wonders like the glass of Roger Bacon's dreams. There was no excitement in “a feeble thing” with magnification well under two diameters. But the concave lenses for the myopic grew better, their focal lengths shorter, the glass clearer; and one of those clever Middelburg artisans, or more than one, saw a new potential. The magnification, close to threefold, was striking.

We can see now, however, that in a way “telescopes” existed before anyone, including the men who made them, were aware of them.” The key point was the development of effective higher magnification. That began near Middelburg when the utility came clear. The rich, the curious and the military seized on the device. Galileo speedily developed the concept, pushed the workable power up to near 30 in a few months and put it to work penetratingly. Once the news got around more than one man realized he had already long possessed the same device, but with low magnification and used in a very different way. Quantity is the hero of this story, as it is of much science in the post-Galilean years.

Check your comprehension

~ What magnification did the early erect-image two-lens instruments have?

~ Who or what is the hero of the story about the invention of the telescope?

1. What dida Padovan student want to do with the first book by Galileo published in Padua?

2. What does the expression “extended senses” mean?

3. What did Galileo do to improve remarkably the early telescope?

4. Was his book The Starry Messenger published earlier than the accounts of scientists and famous amateurs who were gazing at the sky through telescopes at about the same time?

5. Does Prof. Van Helden imply that readers of his book know Latin and Medieval English, French, Italian and Dutch?

6. Did the noble Girolamo Sirtory manage to make a better telescope than Galileo’s?

7. Why were the first telescopes of no great value? Who used them?

8. What was magnification of the first telescopes? Which magnification seemed striking to people of that time?

9. What was the magnification of Galileo’s telescope? Who is the hero of this story?

10. What has happened many times in the history of science in the post-Galilean years?

1) Complete these sentences with the key vocabulary words in the form required

a) breadth of application b) develop the concept c) ‘Art of the Soluble’ d) magnification e) the steam engine f) pattern g) scores of h) a novel idea i) simultaneous j) focal length k) purposeful development l) well under m) inevitability

1. With an instinct for what was later called the ……………, most biochemists confined themselves to more manageable topics.

2. Re-engineering has been embraced publicly by …………… companies, including AT&T, Texas Instruments, Ford, Citicorp, Aetna Life and IBM.

3. All other aspects of the training situation were radically altered in the shift from the …………… to the successive procedure.

4. The steady and …………… of pupils' language and of their skill in its use should be a constant aim of education at all stages and levels.

5. Britain's car manufacturers and oil companies now accept the …………… of lead-free petrol.

6. The group award should be designed to allow …………… and reflect the needs associated with problem solving and task management.

7. An examination of the historical …………… of change serves four main purposes.

8. With a …………… factor of eight and an objective lens diameter of thirty millimetres the binoculars are compact, lightweight and rugged, classic all-purpose glasses.

9. For a given visual angle, image size depends on …………… .

10. This was the invention of ……………, originally devised for draining water from the tin mines, but then adapted by James Watt for driving factory machinery.

11. In the 1960s British Rail came up with …………… for a faster train.

12. This led to an especially sharp decline during the 1960s, from over half a million to …………… 300,000.

13. He hopes to …………… further.

2) Study ГОСТ 8.417-2002. ЕДИНИЦЫ ВЕЛИЧИН: http://nolik.ru/systems/gost.htm

How many physical units are named after great scientists?