National Geographic Society Newsroom

A Brief History of the Astronomical Telescope IV: Did Leonardo Invent the Telescope 100 Years Before Galileo?

  Unbeknownst to me in the 2005 PICMET talk, André Buys was in the audience. A professor at the University of Pretoria in South Africa, Buys was a nuclear engineer, and an avid amateur telescope maker. In the following two years Dr. Buys delved deeply into Leonardo’s surviving codices, and even built a replica of...

Leonardo, Self-portrait (ca. 1510) preserved at the Royal Library, Turin


NASA photograph of the earth shot by Apollo VIII astronaut William Anders on December 24, 1968. Known as “Earthrise,” it is frequently cited as the most influential environmental photograph ever produced. Apollo VIII was the first manned voyage to orbit the Moon. The first landing by astronauts came with Apollo XI


“If you were standing on the moon or on a star, our earth would seem to reflect the sun as the moon does.

.                                                                                                                                                                                   — Leonardo

This is the fourth and final installment on the invention of the astronomical telescope. For me, helping to establish the provenance of the astronomical telescope has been an exciting personal adventure, paralleling many of my achievements in the classroom as a professor of physics and researcher, although my contribution is small.

Wearing my dual caps of artist and scientist, a few years ago I published a book entitled, Math and the Mona Lisa: the Art and Science of Leonardo da Vinci (Smithsonian Books, 2004), and five years later a second book, Leonardo’s Universe (National Geographic Books, 2009). A year after the release of the first book, in 2005 I gave a lecture at the Portland International Center for Management of Engineering and Technology, PICMET ‘05, in Portland, Oregon. There, I mentioned, among a host of innovations that Leonardo had introduced in his art and science, the existence of tantalizing evidence of the design of astronomical telescopes — both reflecting and refracting, but most likely as “mental inventions.” But, I did speculate that Leonardo may just have created an instrument he pointed at the night sky. The time would have been the turn of the 16th century, almost a hundred years before Galileo. Ironically, the year 2009 was celebrated as the ‘Year of Astronomy,’ commemorating the 400th anniversary of Galileo’s epochal invention in 1609 that revolutionized astronomy.

I had based my original hypothesis on some of Leonardo’s diagrams in optics, specifically his study of reflections from curved surfaces and a number of quotes from his Codices. Also for an exhibition in Virginia in 2002 celebrating the 550th Anniversary of Leonardo’s birth, I had collaborated with the late art historian Thomas Somma in organizing the event, “Leonardo — Artist, Scientist, Inventor.” Along with replicas of Leonardo’s inventions, we had selected a copy of one of Leonardo’s drawings, that subsequently appeared on the dust jacket of my book. At the opening of the exhibition, I showed the drawing to two physicist friends, Prof. Norman Ramsey of Harvard and Dr. William D. Phillips of NIST, both uncommonly gifted scientists, both Nobel Prize Winners in Physics. I remember that they were awe struck in seeing the drawing, one of them even exclaiming, “That’s  the telescope!”

In Math and the Mona Lisa, I had quoted Leonardo’s words, “In order to observe the nature of the planets, open the roof and bring the image of a single planet onto the base of a concave mirror. The image of the planet reflected by the base will show the surface of the planet much magnified” (Codex Arundel, c. 1513)

André Buys, Pretoria, SA. (Photo by the author, July 2010)

Unbeknownst to me in the 2005 PICMET talk, André Buys was in the audience. A professor at the University of Pretoria in South Africa, Buys was a nuclear engineer, and an avid amateur telescope maker. In the following two years Dr. Buys delved deeply into Leonardo’s surviving codices, and even built a replica of an instrument that I had speculated was Leonardo’s design for a reflecting telescope. Buys’s research goes a long way toward establishing the validity of the conjecture, and is far more important in establishing the primacy of the invention than my efforts had been.

I ran into André Buys again in 2010 at PICMET ‘10, but this time in the exotic venue of Phuket, Thailand. The morning preceding my keynote talk, we spent almost two hours reviewing the slides in his Power Point Presentation, a presentation initially created for a meeting of the Pretoria Centre of the Astronomical Society of Southern Africa in May 2007. It was immensely gratifying to have the private presentation, and many of Dr. Buys’s slides have been integrated into this blog.

The opening slide in Professor Buys's presentation, "Leonardo da Vinci's Telescope." At the upper left corner of the dust jacket is a crucial study of reflections of light rays falling on a concave mirror. It is flattering to see the cover of my book in the first slide.
Slide 2 "Leonardo's Telescope." Page 59(b) of the Leonardo's Codex Atlanticus, Ambrosiana Library, Milan. (André Buys)
Slide 3. Milestone dates in the invention of the astronomical telescope. Establishing Leonardo's primacy would push back the appearance of the first telescope by almost a century. (André Buys)
LEFT. William Herschel's design of a reflecting telescope (1780) and RIGHT. Isaac Newton's design (1668-1669) (André Buys)

Dr. Buys included in his history of the telescope, the basic design of telescopes, including the two reflectors, Isaac Newton’s (created in 1669 and presented to the Royal Society in the following two years) and William Herschel’s (1780). He also presented the quote from Leonardo:

“As I propose to treat of the nature of the moon, it is necessary that first I should describe the perspective of mirrors, whether plane, concave or convex; and first what is meant by a luminous ray, and how it is refracted by various kinds of media; then, when a reflected ray is most powerful, whether when the angle of incidence is acute, right, or obtuse, or from a convex, a plane, or a concave surface; or from an opaque or a transparent body.”

Elsewhere, Leonardo adds, “It is possible to find means by which the eye shall not see remote objects as much diminished as in natural perspective… and so the moon will be seen larger and its spots of a more defined form.”

Professor Buys includes many of Leonardo’s drawings from a variety of Leonardo Codices — ray diagrams based on experiments on reflection of light from flat and concave surfaces, of designs for machines and tools for polishing flat and concave mirrors, and an apparatus that resembles a modern battlefield weapon, the mortar, but one that can just as easily be a reflecting telescope. The latter is the instrument that Professor Buys created from bronze. The holes at the base, he speculated, might just have been to hold a variety of magnifying glasses, effectively the “eye-pieces” of telescopes. We should add that Leonardo left behind a drawing of a howitzer, shown lobbing shells in parabolic trajectories, but the apparatus is considerably heavier in design.

Leonardo's drawing, evocative of a mortar, could well be the reflecting telescope. The instrument created by Dr. Buys is seen in the lower image, and the holes may well be for hand-held magnifiers. (André Buys)

Buys includes some of Leonardo cosmological pronouncements, including a rejection of the Ptolemaic earth-centered universe, and recognition of universal gravitation:

“The earth is not in the center of the Sun’s orbit, nor at the center of the universe, but in the center of its companion elements, and united with them.” — Leonardo

“The sun does move.”

“Gravity is limited to the elements of water and earth; but this force is unlimited, and by it infinite worlds might be moved if instruments could be made by which the force could be generated.” — Leonardo


Finally, Buys draws his own conclusions:

• “Leonardo had the knowledge and skills to make a telescope. He used a telescope to enlarge the image of the moon. The optical quality was, however, poor and he did not discover the craters on the moon.”

• “Leonardo’s telescope anticipated most of the later inventions, including Newton’s and Herschel’s… ”

His final observation uttered with modesty and caution, “Atalay’s ‘mortar gun’ could have been Leonardo’s Herschellian telescope, but the evidence is not conclusive.”

Buys reports "G. Reeves used Leonardo's drawing to determine the lunar libration ±2°. He then calculated the drawing was made in the early evening on Dec. 12, 1513. The notebook is from 1513-1513." This may have been a time when Leonardo was living in Rome, and forbidden by the Church to carry out further anatomical studies on cadavers. A jealous German optician had renounced him for practicing necromancy. (André Buys)

A suspicious circular smudge appears in the lower right hand sector of the moon. It is the Crater Tycho, invisible to the naked eye. This could be among the more compelling pieces in the puzzle about whether Leonardo had in fact been the first inventor of the telescope.

Leonardo died on 2 May, 1519 in Amboise, France. His patron during the last three years of his life had been Francis I, King of France.

The Scientific Revolution

Historians regard the Scientific Revolution as having been launched by the publication in 1543 of a pair of seminal books — Copernicus’s De revolutionibus and Vesalius’s de humani corporis fabrica. The former, De revolutionibus, introduced a new paradigm for our physical location in the cosmos. Presented initially as a hypothesis, Copernicus’s heliocentric picture, in distinction to the prevailing geocentric, wrested the center of the universe from the earth and placed it in the sun. The latter ushered in scientific anatomical studies, and gave rise to the new field of comparative anatomy, and ultimately revolutionized medicine.

Three decades before the publication of either book, Leonardo (1452-1519) had anticipated many of the developments that would be associated with the Scientific Revolution. He had created anatomical drawings superior to those of Vesalius, and made statements seemingly prefiguring Darwinian evolution. He had performed fundamental studies in optics, and left notes with compelling evidence he had even experimented with both the refracting telescope and the reflector (The Tycho Crater on the moon, invisible to the naked eye, is seen in one of his drawings. Since none of his discoveries were published in his time, and indeed since 75-80% of his papers were lost permanently within a generation or two after his death, his works would not stimulate future development in the sciences. The tragedy of the paragon Renaissance man, universal genius Leonardo, is that although he was in the business of inventing the future, he would not be influencing the future. His scientific endeavors have to be regarded as a false start to the Scientific Revolution.


For most of the slides in this blog and the drama of the discovery, I am deeply indebted to Prof. André Buys, nuclear engineer, amateur telescope maker and scientific sleuth extraordinaire, whom I first met in 2005, and then again in 2010.




About National Geographic Society

The National Geographic Society is a global nonprofit organization that uses the power of science, exploration, education and storytelling to illuminate and protect the wonder of our world. Since 1888, National Geographic has pushed the boundaries of exploration, investing in bold people and transformative ideas, providing more than 14,000 grants for work across all seven continents, reaching 3 million students each year through education offerings, and engaging audiences around the globe through signature experiences, stories and content. To learn more, visit or follow us on Instagram, Twitter and Facebook.

Meet the Author

Bulent Atalay
Bulent Atalay, a scientist, artist and author, has been described by NPR, PBS and the Washington Post as a “Modern Renaissance Man.” He is the author of two successful books on the intersection of art, science and mathematics, with Leonardo, the pre-eminent Renaissance man, serving as the foil. His best selling book, "Math and the Mona Lisa," (Smithsonian Books, 2004) has appeared in 13 languages. Professor Atalay's academic background is in theoretical physics. He travels around the world lecturing at academic institutions and on cruise ships on the "A-subjects," art, archaeology, astrophysics, atomic physics and Ataturk, confessing that he knows much less about the "B-subjects," business, banking, biology and botany... He is the President of the Ataturk Society of America (ASA), dedicated to promoting Ataturk's ideals of science and reason over dogma and superstition, of a secular state with full equality of genders. For more details click on Bulent Atalay