Refracting telescopes use a lens to focus light. The Swedish 1-m Solar Telescope, with a lens diameter of 43 inches, is technically the largest, with 39 inches clear for the aperture.The second largest refracting telescope in the world is the Yerkes Observatory 40 inch (102 cm) refractor, used for astronomical and scientific observation for over a century. The next largest refractor telescopes are the James Lick telescope, and the Meudon Great Refractor.[1]
Most are classical great refractors, which used achromatic doublets on an equatorial mount. However, other large refractors include a 21st-century solar telescope which is not directly comparable because it uses a single element non-achromatic lens, and the short-lived Great Paris Exhibition Telescope of 1900. It used a 78-inch (200 cm) Focault siderostat for aiming light into the Image-forming optical system part of the telescope, which had a 125 cm diameter lens. Using a siderostat incurs a reflective loss. Larger meniscus lenses have been used in later catadioptric telescopes which mix refractors and reflectors in the image-forming part of the telescope. As with reflecting telescopes, there was an ongoing struggle to balance cost with size, quality, and usefulness.
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Transcription
I’ve talked a lot about observing the night sky with your eyes; just simply going out and seeing what you can see. It’s pretty amazing what you can learn just by doing that, and of course that’s all we humans could do for thousands of years. But now we can do better. We can use telescopes. The first person to invent the telescope is lost to history; despite “common knowledge,” Galileo did not invent them. He wasn’t even the first person to point one at the sky, or the first person to publish results! But he was a loud and persistent voice over the years, and his amazing string of discoveries using his crude instrument landed him firmly in the history books. Aggressive self-marketing sometimes pays off. You might think the purpose of a telescope is to magnify small objects so we can see them better. That’s how a lot of telescopes are marketed, but to be honest that’s not exactly the case. If you want to be really general, the purpose of a telescope is to make things easier to see: To make the invisible visible, and to make the things already visible visible more clearly. A telescope works by gathering light. Think of it like a bucket in the rain: The bigger the bucket, the more rain you collect. If your bucket is big enough, you’ll get plenty of water even when it’s only sprinkling out. In the case of a telescope, the “bucket” is an optical device like a lens or a mirror that collects light. We call this device the objective, and the bigger the objective, the more light it collects. Look at your eyes… well, that’s tough, so let’s think about our eyes for a moment. They also work as light buckets, but they only collect light through our pupils, which even under the best of circumstances are less than a centimeter across; a very tiny bucket indeed. But we can do better. To extend the analogy, a telescope is like a bucket with a funnel at the bottom. All that light that it collects is then concentrated, focused, and sent into your eye. It turns a trickle of light into a torrent. The amount of light it collects depends on the area of the objective. That means if you double the diameter of the collector, you’d collect four times as much light, because the area of the collector goes up as the square of the radius. Make a bucket 10 times wider, and you collect 100 times as much light! Clearly, as telescopes get bigger their ability to show us faint objects increases enormously. In fact that was one of Galileo’s first and most important discoveries: Stars that were invisible to the naked eye were easily seen through his telescope, even though it only had a lens a few centimeters across. Those faint stars didn’t emit enough light for his eyes to see them, but when he increased his collecting area with a telescope, they popped into visibility. The primary way telescopes work is to change the direction light from an object is traveling. I can see a star with my eye because light from that star is sent in my direction, into my eye. But most of that light misses my eye, falling to the ground all around me. The telescope collects that light, bounces it around, and then channels it into my eye. When the very first telescopes were built, this changing of the direction of light was done using lenses. When light goes from one medium to another – say, from going through air to going through water or glass – it changes direction slightly. You see this all the time; a spoon sitting in a glass of water looks bent or broken. The spoon is doing just fine, but the light you see from it is getting bent, distorting the image. This bending is called refraction. The way light bends depends on what’s bending it (like water or glass) and the shape of the object doing the bending. It so happens that if you grind a piece of glass into a lens shape, it bends -- or refracts -- the incoming light in a cone, focusing it into a single spot. It’s a light funnel! This refraction has a couple of interesting results. For one thing, the light from the top of a distant object is bent down, and the light from the bottom is bent up. When this light comes to a focus, it means you see the object upside-down! It also flips left and right, which can be a little disconcerting, and takes getting used to when you’re using a refracting telescope. For another thing, the lens can magnify the image. That’s again because the light is bent, and the image created of object observed can appear larger than the object does by eye. It depends on a lot of factors including the shape of the lens, the distance to the object, and how far away the lens is, but in the end what you get is an image that looks bigger. That has obvious advantages; a planet like Jupiter is too far away to see as anything other than a dot to the eye, but a telescope makes it appear bigger, and details can then be seen. When Galileo and other early astronomers pointed their telescopes at the sky, multitudes were revealed: Craters on the Moon, the phases of Venus, Jupiter’s moons, the rings of Saturn, and so much more. The Universe itself came into focus. When astronomers talk about using a telescope to make details more clear, they use a term called resolution. This is the ability to separate two objects that are very close together. You’re familiar with this; when you’re driving on a road at night a distant car coming toward you appears as a single light. When it gets closer, the light separates out — resolves — into two headlights. A telescope increases resolution, making it easier to, say, split two stars that are close together, or to see details on the Moon’s surface. The resolution depends in part on the size of the objective; in general the bigger the telescope objective the better your resolution is. Resolution is more useful than magnification when talking telescopes. Fundamentally, there is a limit to how well your telescope resolves two objects, but there’s no limit to how much you can magnify the image. If you magnify the image beyond what the telescope can actually resolve, you just get mush. Refracting telescopes are great, but they suffer from a big problem: Big lenses are hard to make. They get thin near the edge, and break easily. Also, different colors of light bend by different amounts as they pass through the lens, so you might focus a red star, say, and a blue one will still look fuzzy. No less a mind than Isaac Newton figured a way around this: Use mirrors. Mirrors also change the direction light travels, and if you used a curved mirror you can also bring light rays to a focus. Telescopes that use mirrors are called reflectors. The advantages of reflectors are huge: You only have to polish one side of a mirror, where a lens has two sides. Also a mirror can be supported along its back, so they can be manufactured much larger more easily and for less money. Although there have been many improvements made over the centuries, most big modern telescopes at their heart are based on the Newtonian design, and in fact no large professional-grade telescopes made today have a lens as their objective. Nowadays, it’s all done with mirrors. And that brings us to this week’s aptly named Focus On. The most common question I’m asked (besides, “Hey, who does your hair?”) is, “Hey, Phil, kind of telescope should I buy?” It’s a legitimate question, but it’s very difficult to answer. Imagine someone walked up to you and asked, “What kind of car should I buy?” That’s impossible to answer without a lot more information. Same for telescopes. Do you want to look at the Moon and planets, or fainter, more difficult to spot galaxies? Are you really devoted to this, or is it more of a pastime? Is this for a child or an adult? These questions are critical. Most small ‘scopes are refractors, which are good for looking at detail on the Moon and planets (they tend to magnify the image more than reflectors do). But they’re tricky to use because they flip the image left and right and up and down. Bigger ‘scopes are good for fainter objects, but are more expensive, and can be difficult to set up and use. I hate hearing about a ‘scope that just collects dust because it was bought in haste. So here’s what I recommend: Find an observatory, planetarium, or local astronomy club. They’re likely to have star parties, public observing events, where you can look at and through different kinds of telescopes. Their owners are almost universally thrilled to talk about them — as an astronomer, I can assure that the problem with astronomers isn’t getting them to talk, it’s shutting them up — so you’ll get lots of great first-hand advice and experience. Also, I usually recommend getting binoculars before a telescope. They’re easy to use, fun to use, easy to carry around, and you can get good ones for less money and still see some nice things. Even if you decide not to get more into astronomy as a hobby, they can also be used during the day on hikes and for bird watching. I have a couple of pair of binoculars and I use them all the time. There’s a third aspect to telescopes that’s very important, beyond resolution and making faint things easier to see. They can literally show us objects outside of the range of colors our eyes can see. In the year 1800, William Herschel discovered infrared light, a kind of light invisible to our eyes. In the time since we’ve learned of other forms of invisible light: radio, microwave, ultraviolet, X-rays, and gamma rays. Astronomical objects can be observed in all these flavors of light, if we have telescopes that are designed to detect these flavors of light. Radio waves pass right around “normal” telescopes, ones that we use to observe visible light. X-rays and gamma rays pass right through them as if they aren’t even there. But we’re smart, we humans. We learned that giant metal dishes can and will bend radio waves, and can be formed just like gigantic Newtonian mirrored telescopes. In fact, different forms of light need different kinds of telescopes, and once we figured out how, we’ve built ‘em. We can now detect cosmic phenomena across the entire spectrum of light, from radio waves to gamma rays, and have even built unconventional telescopes that detect subatomic particles from space as well, such as neutrinos and cosmic rays. Because of this, we have learned far more about the Universe than Galileo could have imagined. And we’re in the midst of another revolution, too. The actual biophysics is complicated, but in a sense our eyes act like movie cameras, taking pictures at a frame rate of about 14 images per second. That’s a short amount of time. Photographs, though, can take far longer exposures, allowing the light to build up, allowing us to see much fainter objects. The first photographs taken through a telescope were done in the 1800s. This has led to innumerable discoveries; for example, in the 20th century giant telescopes with giant cameras revealed details in distant galaxies that led to our understanding that the Universe is expanding, a critically important concept that we’ll dive into later in the series. And now we have digital detectors, similar to the ones in your phone camera, but far larger and far more sensitive. They can be dozens of times more light-sensitive than film, able to detect in minutes objects that would’ve taken hours or more to see using film. These digital cameras can also be designed to detect ultraviolet light, infrared, and more. We can store vast amounts of that data easily on computers, and use those computers to analyze that huge ocean of information, performing tasks too tedious for humans. Most asteroids and comets are discovered using autonomous software, for example, looking for moving objects among the tens or hundreds of thousands of fixed stars in digital images. This has also ushered in the era of remote astronomy; a telescope can be on a distant mountain and programmed to scan the sky automatically. It also means we can loft telescopes into space, above the sea of air in our atmosphere that blurs and distorts distant, faint objects. We can visit other worlds and send the pictures and data back home, or put observatories like the Hubble Space Telescope into orbit around the Earth and have it peer into the vast depths of the Universe. I would argue that the past century has seen a revolution in astronomy every bit as important as the invention of the telescope in the first place. In the early 17th century the entire sky was new, and everywhere you pointed a telescope there was some treasure to behold. But with our huge telescopes and incredibly sensitive digital eyes now, that’s still true. We learn more about the Universe every day, just as we learn that there’s more to learn every day, too. That’s one of the best parts of being an astronomer; the Universe is like a jigsaw puzzle with an infinite number of pieces. The fun never ends. And remember: Even with all the wonders revealed by telescopes, your eyes are still pretty good instruments, too. You don’t need big fancy equipment to see the sky. The important thing is to go outside. Look up! That’s fun too. Today you learned that telescopes do two things: Increase our ability to resolve details, and collect light so we can see fainter objects. There are two main flavors of telescope: Refractors, which use a lens, and reflectors, which use a mirror. There are also telescopes that are used to look at light our eyes can’t see, and with the invention of film, and later electronic detectors, we have been able to probe the Universe to amazing depths. Crash Course is produced in association with PBS Digital Studios. This episode was written by me, Phil Plait. The script was edited by Blake de Pastino, and our consultant is Dr. Michelle Thaller. It was co-directed by Nicholas Jenkins and Michael Aranda, and the graphics team is Thought Café.
List
This list includes some additional examples, such as the Great Paris telescope, which also used a mirror, and some solar telescopes which may have more complicated optical configurations. The SST has an optical aperture of 98 cm (39.37"), although the lens itself is 110 cm (43.31"). It is a single element lens whereas most of this list are doublets, with a crown and flint lens elements.
Name/Observatory | Location at debut |
Modern location name or fate | Lens diameter | Focal length | Built | Comments | Image |
---|---|---|---|---|---|---|---|
Great Paris Exhibition Telescope of 1900[2] | Paris 1900 Exposition | Dismantled 1900 | 125 cm (49.21") | 57 m (187 ft) | 1900 | Fixed lens, scrapped. Aimed via a 2 m reflecting siderostat | |
Swedish 1-m Solar Telescope, ORM |
La Palma, Spain |
- | 110 cm (43") total diameter
98 cm (39") clear aperture |
15 m | 2002 | Single element non-achromatic objective[3] combined with reflective Adaptive optics and a Schupmann corrector. The lens is 110 cm in diameter stopped down to 98 cm (39"). | |
Yerkes Observatory[4] | Williams Bay, Wisconsin, USA | - | 1.02 m (40") | 19.4 m (62 ft) | 1897 | Largest in current operation.[5] | |
James Lick telescope Lick Observatory |
Mount Hamilton, California, USA | - | 91 cm (36") | 17.6 m | 1888[2] | ||
Grande Lunette Paris Observatory |
Meudon, France | - | 83 cm + 62 cm (32.67"+24.41") | 16.2 m | 1891 | Double telescope | |
Großer Refraktor Astrophysical Observatory Potsdam |
Potsdam, Deutsches Kaiserreich | Potsdam, Germany | 80 cm + 50 cm (31.5"+19.5") | 12.0 m | 1899 | Double telescope by Repsold and Sons, optics by Steinheil | |
Grande Lunette Nice Observatory |
Nice, France | since 1988 Côte d'Azur Observatory | 77 cm (30.3")[2][6] | 17.9 m | 1886 | Bischoffscheim funded | |
William Thaw Telescope Allegheny Observatory, University of Pittsburgh |
Pittsburgh, Pennsylvania, USA | - | 76 cm (30") | 14.1 m | 1914 | Brashear made, photographic[7] | |
Pulkovo observatory | Saint Petersburg, Russian Empire | Destroyed | 76 cm (30") | 12.8 m (42 feet) | 1885 | Destroyed during WWII, only lens (made by Alvan Clark & Sons) survives. | |
28-inch Grubb Refractor Royal Greenwich Observatory |
Greenwich, London, Great Britain | - | 71 cm (28") | 8.5 m | 1894 | ||
Rolfscher Refraktor[8] | Rathenow, Germany | - | 70 cm (27.6") | 20.8 m | 1949 | Single element non-achromatic objective with Schupmann corrector. | |
Großer Refraktor Vienna Observatory |
Vienna, Austrian Empire | Vienna, Austria | 69 cm (27" ) | 10.5 m | 1880 | Largest refractor in 1880, by Grubb[9] | |
Great Treptow Refractor Treptow Observatory |
Berlin, Germany | - | 68 cm (26.77") | 21 m | 1896 | renamed Archenhold Observatory 1946 | |
Innes Telescope | Observatory Johannesburg, South Africa | Observatory Johannesburg, South Africa | 67 cm (26.5") | 11.6 m | 1909-1925 | Still in operation for educational purposes. By Grubb | |
Yale-Columbia Refractor Yale Southern Station |
Johannesburg, Union of South Africa | Relocated 1952 | 66 cm (26") | 10.8 m | 1925–1952 | Yale-Columbia Refractor moved to Mount Stromlo Observatory in 1952, same telescope as following entry. | |
Yale-Columbia Refractor Mount Stromlo Observatory |
Mount Stromlo, Australia | Destroyed 2003 | 66 cm (26") | 10.8 m | 1952 | Yale-Columbia Refractor – previously located in South Africa. Relocated to Australia in 1952. Destroyed by bush fire on January 18, 2003.[10] | |
Leander McCormick Observatory | Charlottesville, Virginia, USA | - | 66 cm (26") | 9.9 m | 1884 | completed c. 1874, installed 1884 | |
U.S. Naval Observatory | Foggy Bottom Washington, DC, USA | moved to Northwest, Washington, D.C., 1893 | 66 cm (26") | 9.9 m | 1873 | Largest refractor in 1873. Alvan Clark & Sons mounting replaced with Warner & Swasey mounting in 1893. | |
Thompson 26-inch Refractor[11] | Royal Observatory, Greenwich, Great Britain[11][12] | Equatorial Group, Herstmonceux, Sussex[11] | 66 cm (26")[11] | 6.82 m[11] | 1896 | Manufactured by Sir Howard Grubb as a gift from Sir Henry Thompson; originally used at Greenwich on the same mount as a 30 inch reflector[12] | |
Llano del Hato National Astronomical Observatory | Llano del Hato, Venezuela | - | 65 cm (25.6") | 10.6 m | 1955 | ||
Belgrade Observatory[13] | Belgrade, Kingdom of Serbia | Belgrade, Serbia | 65 cm (25.6") | 10.55 m | 1932 | Zeiss made lens, same as at Berlin Observatory | |
Hida Observatory | Gifu, Japan | - | 65 cm (25.6") | 10.5 m | 1972 | ||
65 cm Zeiss Refractor, Pulkovo observatory | Germany[14] | Saint Petersburg, Russia | 65 cm (25.6") | 10.413 m | 1954 | War reparation from Germany[14] In Pulkovo since 1954. | |
Observatory History Museum Mitaka 65 cm | Mitaka, Tokyo, Japan | - | 65 cm (25.6") | 10.21 m | 1929 | Carl Zeiss Jena | |
Berlin-Babelsberg Observatory Berliner Sternwarte Babelsberg |
Berlin, Germany | 65 cm (26") | 10.12 m (33 ft) | 1914 | Berlin Observatory just moved to Potsdam-Babelsberg in 1913; Zeiss lens | ||
Newall Refractor[15] National Observatory of Athens |
UK | Athens, Greece since 1957 | 62.5 cm (24.5") | 8.86 m (29 ft) | 1869 | Built by Thomas Cooke for Robert Stirling Newall. First located at his estate; donated and relocated to Cambridge Observatory in 1889; donated to Athens Observatory and relocated to Mt. Penteli in Greece in 1957. Currently used only for educational purposes as part of the visitor center. | |
Craig telescope | Wandsworth Common, London | Dismantled 1857 | 61 cm (24") | 24.5 m (80 ft) | 1852 | Problem with lens figuring[16] | |
Sproul Observatory | Pennsylvania, USA | Dismantled July 2017 | 61 cm (24") | 11.0 m (36 ft) | 1911 | Currently under restoration to be re-installed in Northwest Arkansas[17] | |
Lowell Observatory | Arizona, USA | - | 61 cm (24") | 9.75 m (32 ft) | 1894 | Alvan Clark & Sons telescope | |
Einstein Tower[18] | Potsdam, Germany | - | 60 cm (23.6") | 14 m | 1924 | Tower telescope, fixed lens fed by a heliostat | |
Zeiss Double Refractor Bosscha Observatory |
Bandung, Dutch East Indies | Bandung, Indonesia | 60 cm (23.6") | 10.7 m | 1928 | ||
Großer Refraktor (Great Refractor)[19]Hamburg Observatory | Bergedorf, Germany | - | 60 cm (23.6") | 9 m | 1911 | by Repsold and Sons, optics (visual + photographic lens) by Steinheil | |
Grubb Parsons Double Refractor | Saltsjöbaden, Sweden | - | 60 + 50 cm (23.6" + 19.7") | 8.0 m | 1930 | Stockholm Observatory in Saltsjöbaden | |
Radcliffe Double Refractor UCL Observatory |
Oxford, UK | Mill Hill, London | 60 + 45 cm (23.6" + 18") | 7.0 m | 1901 | Obtained from the Radcliffe Observatory and installed at UCLO (then known as "ULO") in 1938 | |
Halstead Observatory | Princeton, USA | Roper Mountain Science Center,[20] Greenville, SC | 58.4 cm (23") | 9.8 m (32 ft) | 1881 | by Alvan Clark & Sons | |
Chamberlin Observatory | Colorado, USA | - | 50 cm (20") | 8.5 m (28 ft) | 1891 | First Light 1894 | |
Chabot Observatory | Oakland, California | Oakland, California, USA (2000) | 50 cm (20") | 8.5 m (28 ft) | 1914 | "Rachel", Warner & Swazey Company (Optics John A Brashear Company) Refurbished in 2000 and moved to present location. | |
Van Vleck Observatory | Connecticut, USA | - | 50 cm (20") | 8.4 m (27.5 ft) | 1922 | ||
Carnegie Double Astrograph Lick Observatory |
Mount Hamilton, California, USA | Retired? | 50 cm (20") x 2 | 4.67 m (14 ft) | 1941/1962 (2nd lens) | F7.4 | |
Merz-Repsold 19 inch telescope Brera Observatory |
Milan, Italy | Exposed in Museo Nazionale Scienza e Tecnologia Leonardo da Vinci | 49 cm (19.29") | 7 m (22.97 ft) | 1882 | Largest refracting telescope in Italy | |
Imperial Observatory | Straßburg, German Empire | Strasbourg, France | 48.5 cm (19.1") | 7 m (23 ft) | 1880[21] | Then largest in German Empire | |
18½-in Dearborn Observatory Refractor | Chicago, USA | Evanston, USA | 47 cm (18.5") | 1862 | by Alvan Clark & Sons | ||
Luneta 46 Observatório Nacional |
Rio de Janeiro, Brazil | - | 46 cm (18.4") | 9.7 m | 1921 | T. Cooke & Sons[22][23] | |
Wilder Observatory | Amherst College, Amherst, Massachusetts, USA | - | 46 cm (18") | (25 ft) | 1903 | by Alvan Clark & Sons | |
Flower Observatory | Philadelphia, USA | Dark Sky Project, Lake Tekapo, New Zealand | 46 cm (18") | 6.7 m (22.6 ft) | 1894 | by John Brashear | From 2016 operational at Lake Tekapo, New Zealand. |
Royal Observatory | Cape Colony, British Empire | South Africa | 46 cm (18") | 6.7 m (22.6 ft) | 1897 | [24] | |
Cooke-Zeiss Refractor, Royal Observatory of Belgium[25] |
Uccle, Belgium | - | 45 cm (17.7") | 6.99 m | 1891/1932 | by Cooke & Sons, original 38 cm lens by Merz replaced by 45 cm lens from Zeiss 1932 |
|
Gran Ecuatorial Gautier Telescope La Plata Astronomical Observatory |
La Plata, Argentina | - | 43.3 cm (17") | 9,7 m | 1894 | Gautier | |
Brashear Refractor, Goodsell Observatory | Northfield, Minnesota, USA | - | 41.15 cm (16.2") | 1890 | by John Brashear | ||
Herget Telescope Cincinnati Observatory |
Cincinnati, Ohio | - | 40.64 cm (16") | 1904 | by Alvan Clark & Sons | ||
Vatican Observatory | Castel Gandolfo, Italy | - | 40 cm (16") | 6.0 m | 1881 | by Zeiss | |
Dorides Refractor[26] National Observatory of Athens |
Athens, Greece | Athens, Greece | 40 cm (16") | 5,08 m | 1901 | by Gautier[27] | |
Washburn Observatory | Madison, Wisconsin, USA | In regular use for education and general public. | 39.5 cm (15.56") | 6.7 m (22.6 ft) | 1881 | by Alvan Clark & Sons | |
Dominion Observatory Refractor Dominion Observatory |
Ottawa, Ontario, Canada | Moved to Helen Sawyer-Hogg Observatory (Canada Science and Technology Museum, Ottawa) in 1974[28] | 38.1 cm (15") | 571.5 cm | 1905 | Original achromat doublet by John Brashear replaced with apochomat triplet by Perkin-Elmer in 1958. Currently used for education and outreach. | |
Lunette Arago Paris Observatory |
Paris, France | - | 38 cm (15") | 9 m | 1883 | by Gautier and Henry brothers | |
Double Refractor Fabra Observatory |
Barcelona, Spain | - | 38 cm + 38 cm (15" + 15") | 6 m + 4 m | 1904 | Double telescope by Mailhat, Paris |
|
Gran Ecuatorial Observatorio Astronómico Nacional | Tacubaya, México | - | 38 cm (15") | 4.8 m | 1885 | by Howard Grubb | |
Harvard Great Refractor Harvard College Observatory[29] |
Cambridge, Massachusetts, USA | - | 38 cm (15") | 6.9 m | 1847 | largest telescope in America for 20 years[30] | |
Merz & Mahler Refractor, Pulkovo observatory | Saint Petersburg, Russian Empire | Rescued to Leningrad city in WWII (?) | 38 cm (15") | 6.9 m | 1839 | (original) twin of the Harvard Great Refractor[29] | |
Lunette coudée Lyon Observatory |
Saint-Genis-Laval, France | - | 36.6 cm | 7.66 m | 1887 | Equatorial coudé by Maurice Loewy | |
Telescopio Amici Osservatorio Astrofisico di Arcetri |
Florence, Italy | - | 36 cm | 5 m | 1872 | 28 cm lens by G. B. Amici substituted by Zeiss lens in 1926. Currently used only for educational purposes. | |
Photographic Refractor Leiden Observatory |
Leiden, Netherlands | - | 34 cm + 15 cm (13.4" + 5.9") | 524 cm | 1897 | Double telescope by Gautier and Henry brothers |
|
Astrograph Vienna Observatory |
Vienna, Austrian Empire | Vienna, Austria | 34 cm + 26 cm (13.3" + 10.2") | 3.4 m + 3.4 m | 1885 | Double telescope by Steinheil |
|
Perth Astrograph, Perth Observatory[31] | Old Perth Observatory, Mount Eliza, Western Australia | Perth Observatory, Bickley, Western Australia. Used for public education and outreach | 33 cm (13") | 3.34 m | 1897 | Designed and built by Howard Grubb & Co. Relocated to Bickley ~1966. The original telescope (both camera and guide scopes), mount and dome were re-erected at Bickley | |
Fitz-Clark Refractor Allegheny Observatory, University of Pittsburgh |
Pittsburgh, Pennsylvania, USA | - | 32.02 cm (13") | 4.62 | 1861 | Fitz made, visual/photographic. In 1895 established that Saturn's Rings are made up of particles and not solid.[7] | |
H. Fitz-H.G. Fitz Refractor Henry Ruthurfurd, Private Observatory |
New York City, USA | - | 32.02 cm (13") | 4.62 | 1864 | Fitz made, visual/photographic. Started by Henry, finished by son Henry Giles | |
Bamberg Refractor Urania Observatory (Berlin) |
Berlin-Moabit, Prussia | Berlin, Germany | 31.4 cm (12.36") | 5 m | 1889 | then biggest in Prussia, moved to Insulaner Wilhelm Foerster Observatory in 1963[32] | |
H. Fitz 12.6" refractor | Ann Arbor, Michigan, USA | 32 cm (12⅝") | 508 cm (200") | 1857 | The telescopes were restored to functionality as part of the University of Michigan's 2009 International Year of Astronomy celebration. Viewing nights and open houses[33] have been running since then. | ||
Grubb refractor, Keele Observatory[34] | Oxford, England | Keele University, England (since 1962),
in use for the public |
31.0 cm (12.25") | 4.39 m | 1874 | Still awaiting the reunion with its 19th-century camera used in the Carte du Ciel project and to prove Einstein's general relativity theory during the 1919 solar eclipse. | |
South Telescope, Dunsink Observatory | Dublin, Ireland | Dublin, Ireland | 30 cm (12") | 1868 | by Grubb, the telescope is still used for various outreach activities | ||
Northumberland Telescope,[35] Institute of Astronomy, Cambridge University | Cambridge, England | Still in use by Cambridge University Astronomical Society and Cambridge Astronomical Association | 30 cm (12") | 5.95m | 1833 | Original lens 11.6" made by Cauchoix of Paris, replaced on 150th anniversary by 12" lens designed by R.V. Willstrop,[36] and made by A.E. Optics of Cambridge.[37] | |
Urania Sternwarte (Zurich) | Zurich, Switzerland | - | 30 cm (12") | 5.05 m | 1907 | by Zeiss | |
Griffith Observatory | Los Angeles | - | 30 cm (12") | 5.03 m | 1931 | by Zeiss | |
Clark-Refraktor[38] Vienna Observatory |
Vienna, Austrian Empire | Vienna, Austria | 30 cm (12") | 5.06 m | 1880 | by Clark and Sons | |
Deutsches Museum | Munich, Germany | - | 30 cm (12") | 5.0 m | 1924 | by Zeiss | |
Ladd Observatory, Brown University |
Providence, Rhode Island, USA | Still in use for instruction and public education | 30 cm (12") | 4.6 m (15 ft) | 1891 | Lens designed by Charles S. Hastings and made by John Brashear; telescope mount by George N. Saegmuller | |
Irving Porter Church Memorial Telescope Fuertes Observatory, Cornell University |
Ithaca, New York | Still used for instruction and public outreach. | 30 cm (12") | 4.57 m (15 ft) | 1922 | Optics by John Brashear, mounting by Warner & Swasey. | |
Jewett Observatory | Pullman, Washington, USA | Used for instruction and pleasure | 30 cm (12") | 4.57 m (15 ft) | Assembled from older parts 1953[39] | Alvan Clark & Sons | |
Silesian Planetarium and Astronomical Observatory | Katowice/Chorzów, Silesia, Poland | 30 cm (12")[40] | 4.5 m | 1955 | Largest and oldest Planetarium and Astronomical Observatory in Poland.[41] The 3rd largest in Eastern Europe (east of Germany), after Pulkovo Observatory in Saint Petersburg, Russia and Belgrade Observatory in Belgrade, Serbia | ||
University of Illinois Observatory | Urbana, Illinois, USA | Used for instruction and pleasure | 30 cm (12") | 4.57 m (15 ft) | 1896 | by John Brashear, National Historic Landmark, still used for instruction | |
Equatorial Refractor Sydney Observatory |
Sydney, Australia | Still in use for education and public outreach | 28.956cm (11.4") | - | 1874 | by Hugo Schroeder, used to view transit of Venus that occurred on 9 December 1874 | |
Mitchel Telescope Cincinnati Observatory |
Cincinnati, Ohio, USA | - | 28 cm (11") | 1843 | Merz & Mahler; Oldest professional telescope still used weekly by the public[42] | ||
Brashear Refractor Nicholas E. Wagman Observatory |
Pittsburgh, Pennsylvania, USA | - | 28 cm (11") | 1910 | John Brashear, Amateur Astronomers Association of Pittsburgh[43] | ||
Great Refractor Kuffner Observatory |
Vienna, Austria | - | 27 cm + 15.6 cm (10.6" + 6.1") |
350 cm + 294 cm | 1884 + 1890 | Double telescope by Repsold and Sons, optics by Steinheil |
|
Repsold Refractor (10-duims) Leiden Observatory |
Leiden, Netherlands | - | 26.6 cm (10.5") | 399,5 cm | 1885 | Repsold and Sons, optics by Alvan Clark & Sons | |
Äquatoreal (Equatorial)[44] Hamburg Observatory |
Millerntor Observatory, Hamburg, Germany | Hamburg Observatory, Bergedorf, Germany | 26 cm (10.2") | 3 m | 1867 | Repsold and Sons, optics by G. & S. Merz | |
Hume Cronyn Memorial Observatory | Western University London, Ontario, Canada |
- | 25.4 cm (10") | 4.386 m (172") | 1940 | by Perkin-Elmer Corp. Glass from Chance Brothers. | |
Mills Observatory | Dundee, Scotland (1951) | 25 cm (10") | 1871 | by T. Cooke & Sons. Training telescope at St. Andrews 1938–1951 | |||
Coats Observatory | Paisley, Scotland (1898) | 25 cm (10") | 1898 | by Howard Grubb. Replaced 5" refractor by Thomas Cooke, installed in 1883. | |||
Blackett Observatory | Marlborough College Wiltshire, England |
- | 25 cm (10") | 1860 | by Thomas Cooke. | - | |
Quito Astronomical Observatory | Quito | La Alameda park | 24 cm (9.6") | 1875 | An operational 1875 Merz telescope and one of the Oldest Observatories in South America, founded in 1873. | ||
Fraunhofer Refractor, United States Naval Observatory (Foggy Bottom) | Foggy Bottom, D.C., USA | 24.4 cm (9.6") | 1844 [45] | ||||
Fraunhofer-Refraktor Berlin Observatory |
Berlin-Kreuzberg, Deutsches Kaiserreich | Moved 1913 to Munich, Germany | 24 cm (9.6") | 4 m (13.4′) | 1835 | Used to discover Neptune; in Deutsches Museum, München since 1913[46] | |
Great Dorpat Refractor (Fraunhofer) Dorpat/Tartu Observatory (Old Building) |
Dorpat, Governorate of Livonia | Tartu, Estonia | 24 cm (9.6") | 4 m (13.4′) | 1824 | "...the first modern, achromatic, refracting telescope."[47][48] |
See also
- Lists of telescopes
- List of largest optical reflecting telescopes
- List of largest optical telescopes in the 20th century
- List of largest optical telescopes in the 19th century
- List of largest optical telescopes in the 18th century
References
- ^ Caplan, James; Le Guet Tully, Françoise (2008). "2008JHA....39..131C Page 131". Journal for the History of Astronomy. 39 (134): 131. Bibcode:2008JHA....39..131C. doi:10.1177/002182860803900114. S2CID 125660771.
- ^ a b c Hollis, H. P. (1914). "Large Telescopes". The Observatory. 37: 245–252. Bibcode:1914Obs....37..245H.
- ^ solarphysics.kva.se The Swedish 1 m Solar Telescope "By using a lens of a single glass, excellent image quality is obtained through very narrow filters that isolate a single wavelength or color." Archived 2008-06-16 at the Wayback Machine
- ^ "The 40-inch". astro.uchicago.edu. Archived from the original on 2009-02-25. Retrieved 2009-02-27.
- ^ "Yerkes Observatory | observatory, Williams Bay, Wisconsin, United States". Encyclopedia Britannica. Retrieved September 8, 2019.
- ^ Hutchins, Roger (2008). British University Observatories, 1772–1939. Aldershot, England: Ashgate Publishers. ISBN 978-0-754-63250-4. Page 252.
- ^ a b "World's Biggest Refractors". Archived from the original on 2008-11-21. Retrieved 2009-03-30.
- ^ "Startseite – Stadt Rathenow". www.rathenow.de.
- ^ "World's Biggest Refractors". Archived from the original on 2011-07-16. Retrieved 2009-08-14.
- ^ Mount Stromlo Observatory brochure, page 12, The 26" Yale-Columbia Refractor, Australian National University, 2004, accessed 19 April 2008
- ^ a b c d e "Telescopes". The Observatory Science Centre. 2018. Retrieved 11 August 2018.
- ^ a b "Royal Observatory, Greenwich". The Observatory. 20: 283–286. 1897. Bibcode:1897Obs....20..283.
- ^ "ASTRONOMICAL OBSERVATORY BELGRADE". www.aob.bg.ac.rs.
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- ^ "Welcome to the Online Museum of the Craig Telescope". www.craig-telescope.co.uk.
- ^ Large telescope moves to Northwest Arkansas to further STEM recruitment goals
- ^ Saar, Bettina. "Teleskop – Deutsch". www.aip.de (in German).
- ^ Hünsch, Matthias. "Großer Refraktor". www.hs.uni-hamburg.de.
- ^ "Welcome to Roper Mountain Science Center!". www.ropermountain.org. Archived from the original on 2011-07-27. Retrieved 2010-11-13.
- ^ "The Large Refractors Of The World". chestofbooks.com.
- ^ Harper, W. E. (1929). "List of Refracting and Reflecting Telescopes". Journal of the Royal Astronomical Society of Canada. 23. Royal Astronomical Society of Canada: 351–355. Bibcode:1929JRASC..23..351H. See page 352.
- ^ Taylor, E. Wilfred; Wilson, J. Simms; Maxwell, P. D. Scott. At the Sign of the Orrery: The Origins of the Firm of Cooke. Troughton and Simms, Limited. (Not dated). p. 49.
- ^ Hopkins, Albert A; Bond, A. Russell. Scientific American Reference Book. A Manual for the Office, Household and Shop. Munn & Company, 1905. (copyright 1904), Munn & Company
- ^ "Bruxelles – AstroEquatoriales". astroequatoriales.free.fr.
- ^ "Dorides Refracting Telescope – The Hellenic Archives of Scientific Instruments". www.hasi.gr.
- ^ Gautier, Paul Ferdinand. "The Hellenic Archives of Scientific Instruments". www.hasi.gr.
- ^ "CSTM Homepage – Canada Science and Technology Museum". www.sciencetech.technomuses.ca.
- ^ a b Group, CfA Web Services (4 October 2023). "Harvard College Observatory: Great Refractor". www.cfa.harvard.edu.
- ^ "Telescope: Harvard 15-inch Refractor". amazing-space.stsci.edu.
- ^ "Perth Observatory – Star Viewing Nights and Tours". Retrieved September 8, 2019.
- ^ "AllZeit Online News". Archived from the original on 2004-11-27. Retrieved 2009-03-28.
- ^ "Detroit Observatory Open Houses | U-M LSA Astronomy". lsa.umich.edu. Retrieved September 8, 2019.
- ^ University, Keele. "Keele Observatory, Keele University". Keele University. Retrieved September 8, 2019.
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- ^ "Dr Roderick V Willstrop | Institute of Astronomy". www.ast.cam.ac.uk. Retrieved September 8, 2019.
- ^ "Northumberland Telescope | Institute of Astronomy". www.ast.cam.ac.uk. Retrieved 2019-03-07.
- ^ "Objekt des Monats: Refraktor von Clark & Sons". bibliothek.univie.ac.at.
- ^ "Astronomy Program – Jewett Observatory". astro.wsu.edu.
- ^ "Planetarium i Obserwatorium im. Mikołaja Kopernika w Chorzowie". www.planetarium.edu.pl.
- ^ "Planetarium i Obserwatorium im. Miko?aja Kopernika w Chorzowie". Archived from the original on 2011-07-18. Retrieved 2010-07-22.
- ^ "History". Archived from the original on 2010-12-13. Retrieved 2010-12-22.
- ^ "Amateur Astronomers Association of Pittsburgh". Retrieved September 8, 2019.
- ^ Hünsch, Matthias. "Äquatoreal". www.hs.uni-hamburg.de.
- ^ The General History of Astronomy. Cambridge University Press. 1900. ISBN 978-0-521-24256-1.
- ^ Daugherty, Brian. "Berlin – History of Astronomy in Berlin". bdaugherty.tripod.com. Archived from the original on 2011-07-19. Retrieved 2009-03-28.
- ^ Waaland, J. Robert (1967). "Fraunhofer and the Great Dorpat Refractor". American Journal of Physics. 35 (4): 344. Bibcode:1967AmJPh..35..344W. doi:10.1119/1.1974076.
- ^ "Fraunhoferi refraktor". www.obs.ee.
Further reading
- Ian Ridpath (2001). The Illustrated Encyclopedia of the Universe. Watson-Guptill Publications. ISBN 978-0-8230-2512-1.
- List of largest refracting telescopes circa 1914 List.