Changing Planet

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

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.




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
  • Andrew Seymour

    Great article and considering everything else that da Vinci investigated, it only makes sense that he may have used a form of telescope. One can only imagine what Leonardo would be doing with today’s technology!

  • j

    Fascinating article! Congratulations to you for making the discovery and to Professor Buys for building the model of Leonardo’s reflecting telescope.

  • Elizabeth Atalay (

    As first seen at!! Wow, this is such a fascinating discovery, sure to create a buzz in the scientific world.

  • Astronomie

    All the above legends are the god of science and Reflecting Telescopes. Due to them only we are able to step out to Moon and Mars

  • Kyle Dahlem

    I’m not surprised to learn of Leonardo’s vision of the reflecting telescope as his creative genius is unparalled.
    I marvel at Bulent’s tenacity and research that reveals this fact. It could be said that Bulent is basking in reflected genius.

  • best telescope

    refracting telescope is better than reflecting, just wondering if there are any handy refracting telescope for star gazing trip.

    Refracting Telescopes


  • chukwuemeka peter chukwuemerie

    Wow! These scientists in physics field are really mad, no wonder they do abnormal stuff. What a mystery by God, they discovered what have not been existed. Imagine telescope,right now is being used in the world. What a metaphysics. However, I love physics, knowing I will still be like them to discover what have not be existed.

  • Marvin Bolt

    Interesting article and provocative suggestions. Alas, there’s not really much solid evidence to support this claim, and considerable evidence against it. Leonardo sketched many ideas that look like later inventions, but we know that it took a long time before those inventions were possible, much less made: flying machines, helicopter, tank, calculator, various cannons, and now, supposedly, a telescope. There’s little chance this apparent telescope would have actually worked, and for reasons physicists know. It’s very difficult to make a reflector, far more difficult than a refractor. Aside from it being highly unlikely Leonardo could have achieved a level of reflectivity sufficient for a telescopic mirror, the ability to shape a telescopic mirror (a difficult task even in the 19th century) would have certainly been beyond even his ability. At least there’s nothing in this article to indicate otherwise. Instead, this article includes a lot of “might haves” that are highly suggestive and provocative but without compelling evidence. As far as “anticipating” later developments, well, that’s a problematic notion that historians have rightly long eschewed. We’re much better off looking at what Leonardo did, and could have done, and celebrating his extraordinary gifts, than unnecessarily crediting him with inventions beyond even his exceptional talents. Until more compelling evidence can be summoned, a working telescope should be on that list. Professors Atalay and Buys should be congratulated on carrying on out their initial investigations on this fascinating possibility, and encouraged to explore it in more detail. A much better understanding and analysis of contemporary optics and optical literature, geometrical optics, and their relationship to image formation and burning mirrors for starters, will be necessary to provide more substantive evidence of the claim made.

  • Bulent Atalay

    In response to Dr. Bolt’s comment.

    I apologize for the delayed approval for publication of your comment. I was traveling in French Polynesia when I received a note from Word Press that your note had been received. Unhappily, I had access to only an iPad, which you may know is as difficult for typing lengthy messages as is an iPhone. You make a number of salient points, and you are right to be skeptical.

    At the outset, I have to admit that I am not an experimental physicist, nor am I an observational astronomer; I am also not a historian of science. I am a theoretical or mathematical physicist, and I have always done art. As a scientist/artist, I came to realize many years ago, perhaps since the very first time that I began browsing though Leonardo’s Codices, that what I was doing in integrating art/mathematics and science, echoed what Leonardo had done five centuries earlier. But he had done this better than anyone else. Moreover, I function with a modern education, whereas Leonardo was an autodidact.

    As with many other Leonardisti, I have felt endlessly frustrated by Leonardo. Part of this was his fault — he was doing his studies for his own edification, and not for publication. He wrote almost everything in mirror script, backwards. And he flittered from one beckoning problem to another. But then, it certainly was not his fault that so much of his papers — perhaps as much as three-quarters of the original — were lost. What I’ve learned in going through the surviving codices, especially the Codices Atlanticus and Windsor, is that one can never be surprised by what one encounters in those note. Among the reams of studies on reflections from curved surfaces, there are drawings that show the focal point of a concave reflector is one-half the radius-of-curvature, a reasonable approximation for long focal distance mirrors. Also among the notes are the design for a lathe and for a mirror grinder to produce concave reflectors. (He would not have known the mathematics showing that a parabolic reflector is required to eliminate color aberration, as did Isaac Newton.) In his design Leonardo does not show an eyepiece as in the Newtonian reflector, but then in a Herschellian Reflector one peers down the edge of the opening in the tube. Professor Buys, who constructed a replica of Leonardo’s design to scale with the drawing, speculates that small peg holes near the base of Leonardo’s design may have been for the handles of magnifier glasses tantamount to separate magnifying eye-pieces. I am attaching several of Leonardo’s figures from the Codices, along with Dr. Buys’s replica, replete with the specs.
    Regarding the reflecting surface, Buys explains that speculum mirrors were used in the 15th century. (Comprised of “… 2/3 parts copper and 1/3 tin, speculum is an exceptionally hard and brittle metal. The technology to produce speculum mirrors has been largely lost as this alloy was last produced in the 19th century.”) As an artist, Leonardo was used to producing highly polished surfaces on which to paint. Except when he painted murals, his works were always on poplar boards, never on canvases. In my book, Leonardo’s Universe (National Geographic Books, 2009) a passage reads:

    “In Leonardo’s life, which spanned the Middle Renaissance and ushered in the High Renaissance, artists painted on wooden panels. These had to be prepared methodically. The panels were dried; then they were sanded and covered with a layer of liquid gesso—a coating made by mixing powdered gypsum with glue made from rabbit or other animal skins. The wood panels would then be rubbed vigorously with polished hematite, known for its hardness, until the desired smoothness had been achieved. Leonardo, the consummate scientist, described one of his own favorite gessoes in a notebook, a formula markedly different from the more traditional approach for preparing a panel for egg tempera: “Coat [the panel] with mastic and white turpentine of the second distillation … then give it two or three coats of aqua vitae in which you have dissolved arsenic or some other corrosive sublimate … apply boiled linseed oil so that it will penetrate every part, and before it cools rub it well with a cloth to dry it. Over this apply liquid white varnish with a stick, then wash with urine.”
    In the passage, the key clue is the “rubbing with the [polished] hermatite,” a process that requires the application of countless hours of elbow grease, almost always done by apprentices, in polishing wooden panels or, I would guess, for polishing concave mirrors.

    Indeed, one does not have to be a mindless Leonardo sycophant not to be surprised in encountering futuristic technology. Along with most people trained in the hard sciences, I am used to saying that if something can be done in a certain way, it does not mean that it was indeed done in that way. (In 1947 the Norwegian explorer Thor Heyerdahl had used such logic, sailing 6,000 km from South America to the Polynesian Islands in a reed boat to prove that the islands could have been populated in that way, therefore they had to have been populated in that way.)

    But at the end of the day, there is still tantalizing, circumstantial evidence that Leonardo really did make observations of the moon with a reflecting telescope, and the best evidence is a drawing of the surface of the moon showing a small circular area precisely where the Crater Tycho is located. (And, as you must know, this crater is not visible without a fairly good telescope.)
    In the sciences, authority is rarely invoked to make a point, as it is frequently in the humanities. Arguments have to stand or fall by their own weight, and not by the word of an authority. Nonetheless, I will invoke the names of three exceptionally good experimentalists, all friends, who have also expressed cautious optimism about the hypothesis regarding Leonardo having created the first astronomical telescope — Norman Ramsey (Harvard physicist, Nobel 1989), Bill Phillips (NIST physicst, Nobel 1997) and John Mather (NASA astrophysicist Nobel 2006). I think I am about 75% convinced that Leonardo made an astronomical telescope and pointed it at the heavens.

  • Marvin Bolt

    I sent the following reply to Dr Atalay and neglected to post it publically, so here is a slightly modified public version.

    I am delighted and honored by your thorough and engaging reply! I was not sure if we might be able to hold a conversation on the topic, so this is very rewarding for me. I do hope that my original comments sufficiently conveyed my appreciation for your work, and the intriguing suggestions raised by it. Rather than quashing and dismissing them, I wanted to encourage additional investigation, and of a particular sort especially. Before addressing the details of your comments, perhaps you will indulge a few general remarks to clarify my concerns.

    Perhaps the best way to start is with your comment at the end. I am not convinced about the call to expertise being less prevalent in the sciences than in the humanities, but that is not the reason I make mention. Rather, it is about the kind of expertise than could be, and needs to be, applied here. You quite rightly have involved considerable, one might say dramatic, expertise on optics that I (and most historians) certainly do not have or even have access to. And that expertise is an essential ingredient in assessing Leonardo’s claims. But it is not the only expertise needed to make a proper assessment. In a bold moment, I might even claim that it might not be the most critical kind of expertise needed.

    An analogy might help illustrate my point. Consider another research topic of mine, the Star of Bethlehem in the gospel of Matthew. There is plenty of room for a lot of people to work on it, but quite often in the past, the person working on it was a contemporary astronomer looking for some bright or explosive event, or remnant thereof. That’s a good skill set to bring to the table, but in this case, not always a particularly helpful one. We need theological insight to help understand the original text, historical sensibilities to shed light on astronomical and astrological practices 2000 years ago, and knowledge of classical texts to understand the ancient language of astronomical observations and beliefs. [I note that it was, in fact, a modern research astronomer (Michael Molnar) who brought those insights together to provide by far the best analysis of the Star of Bethlehem, so I am quite happy to acknowledge the value of a modern scientist contributing to a historical topic.] Similarly, in the present case, we need diverse skills to interpret Leonardo, art history and optical history in particular. In this case, your modern physics / optics background is a valuable, essential skill for assessing the physics, an appropriate one, unlike in the Star of Bethlehem example. But it can also lead astray by reading modern understandings back into the texts and drawings that are not there, and drawing inferences that are not warranted. Historians are not by any means perfect at doing so, but by training are clued in to the dangers of presentism and on alert to recognize and minimize it. Your comment that you have an advantage because you function with a modern education whereas Leonardo was an autodidact is precisely the sort of observation that sets off the presentist radar detector. I suspect that you and your colleagues are quite sensitive to this problem of presentism, and have intuitively tried to minimize it, but might not always recognize when it rises. I say this with a cautionary rather than accusatory intent. I simply encourage you to engage historical experts on optics to reduce its impact even more. [In the original reply, I suggested contacting them and reading some research on historical investigations on the history of the telescope, such as found in a recent volume that can be downloaded at , the article beginning at p 129 in particular]

    So, on to Leonardo, who challenges any one of us and any team of us with his virtuosity and breadth of interest. The one thing we learn, you note, is never to be surprised! Indeed. And here is where physicists have one significant advantage over historians. I say this having a background in both. The latter are obsessed with what did happen, and finding compelling evidence that it did; the former are obsessed with exploring the possibilities of what could have happened. So looking at historical actors like Leonardo enables a physicist to tinker to see what might have, what could have happened in logical, historical space, and to be much more flexible in recreating those possibilities than might historians, who tend to be more conservative. I submit, though, that the combination of those skills is what is needed here.

    Given the encouragement not to be surprised, I guess I am not surprised about Leonardo’s lathe and other drawings. The danger, if I can be so dramatic, in interpreting these and other sketches is that we see what we want to see or see similarities to what later folks drew and made. I will not repeat the caveats about making inferences about other drawings by Leonardo about devices that were not, or could not have been, built as I think the implications are clear.

    Onto telescopes. There are a lot of optical sketches by Leonardo, and I have no deep knowledge of them. I rely on your own careful investigation of them, but to understand them fully would require an investigation of contemporary optical practice and whether or not Leonardo was doing experimental or mathematical investigations, or both. One cannot simply assume that these drawings meant to him what they might mean to a later investigator. One of your comments is particularly applicable: (You wrote: He would not have known the mathematics showing that a parabolic reflector is required to eliminate color aberration, as did Isaac Newton.) As you know even better than I, the difference between a spherical and parabolic mirror is very little, on the order of a wavelength of light, and that makes the difference between a good mirror and a lousy one. People struggled to make good mirrors in the 18th century, both with respect to shape and with respect to reflectivity. Herschel (on whom I wrote my dissertation, and whom I would love to associate with Leonardo!) conducted a lot of experiments to increase the reflectivity. He was the first to use reflectors as a useful research tool. The reason: no one else could produce a reflector with a sufficiently large and reflective mirror. I’ve looked at late 17th century and early 18th century reflecting telescopes, and while they are beautiful objects that would have been more useful than Galileo’s telescope, they are harder to make than refractors, much harder, and no one did any significant work with reflectors until Herschel.

    Yes, speculum mirrors were used in the 15th century, but they were not of optical quality by any stretch. They were not sufficiently reflective or smooth, or accurately shaped for optical usage, much less optical usage in astronomy. At this point, reading the article cited above would be useful for more details about why it is problematic to ascribe the invention of a reflecting telescope in the 16th century (much less the 15th). By your own admission, Leonardo would not have not of the parabolic requirement – it strikes me as quite implausible that he would have chanced upon it by accident in constructing a mirror.

    Now as to optical design, you note that Leonardo did not show an eyepiece, but you helpfully point out that it might have used a Herschelian design. That’s an intriguing idea, but it goes beyond evidence, as you must realize. The small holes suitable for pegs is an intriguing suggestion, but calling them peg holes begs the question! It is ingenious, plausible, and highly speculative. More to the point, was it possible to make an optical magnifying glass that could function as that kind of lens at that time? While I have some doubts I could be convinced otherwise, but your argument hinges on its being not only possible but actual. And even if that is possible, I think the evidence about the difficulty of making high-quality mirrors makes the conclusion rather problematic. I am cheering for Leonardo as much as the next guy, but I do not yet see any compelling evidence. Suggestive sketches, yes. But inferring from them the actual construction of telescopes, not nearly so much.

    Finally, the matter of crater Tycho, which first shows up in labeled form in the mid-1600s after being viewed through a new kind of telescope, one with a multiple lens eyepiece. Again, I am quite hesitant to say that the sketch should be considered evidence of a telescopic viewing of the crater. Admittedly, I cannot see the details of the sketch in large enough format to make a definitive decision on it, but from what I can see, I am not buying.

    So there it is. The circumstantial evidence is not, in my opinion, anywhere near sufficient to lend much support to the idea. I do think it is provocative, and intriguing, and very much worth further investigation. You have done very interesting work on it, and clearly have optical expertise to see what is possible. It would be thrilling if it turned out to warrant the conclusions you have offered. I hope I have provided sufficiently compelling reasons to prompt further investigation that makes use of historical expertise to evaluate what actually did happen.

    I am very interested to see where this research leads. If it shakes up our understanding of optics and the history of the telescope, that would be remarkable, noteworthy, and worth celebrating. Any project that combines science, art, and history is one that has great public appeal – adding Leonardo into the mix makes it all the more intriguing and irresistable. I think it best that we keep the champagne corked until the evidence is more compelling.

    With very best wishes,


  • Nkosinathi Nompandana

    Well done Prof: Buys, i’m proud to be your student in University of Pretoria

  • katesisco

    The immediate comparison to the Bosnian discovery of a source deep underground connected to the pyramid now known to be almost 25,000 y old, indicates that it is an astronomical telescope. Perhaps designed to use collimated light.

  • […] Brief History of the Astronomical Telescope — National Geographic […]

  • acne

    I am so glad I found this weblog. Thank you for the data. You make a great deal of great points in your article. Rated 5 stars!

  • promote me pro plugin

    Excellent post. I simply stumbled upon your blog and also wanted to claim that I’ve really appreciated exploring your blog articles. Regardless I will be subscribing to the nourish and i also hope you write again shortly!

    • Thank you for the kind words. I have two more installments in the last series, “Leonardo’s Bridge,” that I still have to write. Then I will go onto entirely different subjects that are beckoning. I still have a couple of books that I am also working on, but all in good time. Warm regards, Bulent

  • 手機套

    Wow it is an incredible post. I want to bookmark your post and check out your weblog website prior. Thanks once more for the excellent publication.

  • Dr. Robert D. Elliott

    I am won over by Dr. Atalay and Buyers’ arguments. I have been a Leonardo scholar for 25 years, and have studied with Martin Kemp of Oxford. I have published two papers on Leonardo. I can easily see the crater Tycho in Leonardo’s drawing.
    In the multi scholarly volume Leonardo DaVinci published on the anniversary of Leonardo’s birth, there is an extensive article by the mathematician Domenico Argentieri on the Leonardo’s optics and telescope verifying that Leonardo’s calculations for mirror grinding and their results …”Leonardo did actually construct his telescope, because it was only by means of experiment that he could have observed the phenomena he describes, only experimentally and empirically that he could give the distance between the lenses, distances so different and yet so correct for the observation of distant and nearby objects. ” p. 424. ” codex Atlanticus has a drawing of a machine for grinding concave mirrors with a radius of curvature of 20 ells; this proves that Leonardo was engaged in making mirrors of with a focal length of 6 meters, with which he should have obtained a considerab,e magnification. “. “In the Codex Arundel ,… it is shown that the mirror with the smaller relative aperture is practically free of spherical aberration, which takes on prohibitave values in the mirror with the larger relative aperture …Thus it is a really extraordinaryand astonishing conclusion, when it is compared with the conclusion that modern optics has arrived at , namely, that if a concave spherical mirror with a diameter of 16 centimeters is not to go beyond the Rayleigh limit, the famous quarter-wavelength limit, it’s relative aperture should not exceed f:8 . …we can easily see that the only way in which Leonardo could have come to this conclusion was by the most attentive examination of the REAL IMAGE formed by the concave mirror in its focal plane.”
    . are but a few of his conclusions.

    I have had three mathematicians to review these findings, and all concurr that the mathematics of Leonardo would have produced a mirror of good quality.

  • Bob Walcott

    I read an description of DaVinci’s invention, or at least design, of the telescope in a large book, with selections from his notebooks and detailed analyses by experts, that was published in Italy in the 1930s but was swallowed up by the chaos of WW2. (I don’t recall the name, unfortunately.) What convinced me that he understood the principles, even if he never built one, is a page with calculations that the chapter editor (a physicist) convincingly argues derives practical focal lengths and f/ value relations obvious to any practical telescope builder, but which make no sense otherwise (say for a mortar). I have a physics degree, and renovate/resell old telescopes and other optics as a hobby/side job. Sorry to be so vague, but I didn’t buy the book ($100+ used, mostly about art) so I’m working from memory. I assume it’s in some bibliography and there must be copies around if anybody is interested. (If other chapters are as good, it’s worth getting or reading.)

About the Blog

Researchers, conservationists, and others share stories, insights and ideas about Our Changing Planet, Wildlife & Wild Spaces, and The Human Journey. More than 50,000 comments have been added to 10,000 posts. Explore the list alongside to dive deeper into some of the most popular categories of the National Geographic Society’s conversation platform Voices.

Opinions are those of the blogger and/or the blogger’s organization, and not necessarily those of the National Geographic Society. Posters of blogs and comments are required to observe National Geographic’s community rules and other terms of service.

Voices director: David Braun (

Social Media