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small in aperture that many astronomical objects were simply not observeable until the advent of long-exposure photography, by which time the reputation and quirks of reflecting telescopes were beginning to exceed those of the refractors. Despite this, some discoveries include the Moons of Mars, a fifth Moon of
Jupiter, and many double star discoveries including Sirius (the Dog star). Refactors were often used for positional astronomy, besides from the other uses in photography and terrestrial viewing.
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542:, who further developed this technology and also developed the Fraunhofer doublet lens design. The breakthrough in glass making techniques led to the great refractors of the 19th century, that became progressively larger through the decade, eventually reaching over 1 meter by the end of that century before being superseded by silvered-glass reflecting telescopes in astronomy.
40:
183:
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In the 19th century, refracting telescopes were used for pioneering work on astrophotography and spectroscopy, and the related instrument, the heliometer, was used to calculate the distance to another star for the first time. Their modest apertures did not lead to as many discoveries and typically so
868:
One of the more famous applications of the refracting telescope was when
Galileo used it to discover the four largest moons of Jupiter in 1609. Furthermore, early refractors were also used several decades later to discover Titan, the largest moon of Saturn, along with three more of Saturn's moons.
921:
By the 18th century refractors began to have major competition from reflectors, which could be made quite large and did not normally suffer from the same inherent problem with chromatic aberration. Nevertheless, the astronomical community continued to use doublet refractors of modest aperture in
702:
or special, extra-low dispersion (ED) glass in the objective and produce a very crisp image that is virtually free of chromatic aberration. Due to the special materials needed in the fabrication, apochromatic refractors are usually more expensive than telescopes of other types with a comparable
697:
have objectives built with special, extra-low dispersion materials. They are designed to bring three wavelengths (typically red, green, and blue) into focus in the same plane. The residual color error (tertiary spectrum) can be an order of magnitude less than that of an achromatic lens. Such
251:. The telescope converts a bundle of parallel rays to make an angle α, with the optical axis to a second parallel bundle with angle β. The ratio β/α is called the angular magnification. It equals the ratio between the retinal image sizes obtained with and without the telescope.
416:
in 1611, is an improvement on
Galileo's design. It uses a convex lens as the eyepiece instead of Galileo's concave one. The advantage of this arrangement is that the rays of light emerging from the eyepiece are converging. This allows for a much wider field of view and greater
421:, but the image for the viewer is inverted. Considerably higher magnifications can be reached with this design, but, like the Galilean telescope, it still uses simple single element objective lens so needs to have a very high focal ratio to reduce aberrations (
533:
Dollond achromats were quite popular in the 18th century. A major appeal was they could be made shorter. However, problems with glass making meant that the glass objectives were not made more than about four inches (10 cm) in diameter.
335:. It used a convergent (plano-convex) objective lens and a divergent (plano-concave) eyepiece lens (Galileo, 1610). A Galilean telescope, because the design has no intermediary focus, results in a non-inverted (i.e., upright) image.
800:. Since a lens can only be held in place by its edge, the center of a large lens sags due to gravity, distorting the images it produces. The largest practical lens size in a refracting telescope is around 1 meter (39 in).
254:
Refracting telescopes can come in many different configurations to correct for image orientation and types of aberration. Because the image was formed by the bending of light, or refraction, these telescopes are called
668:
The long achromats, despite having smaller aperture than the larger reflectors, were often favored for "prestige" observatories. In the late 18th century, every few years, a larger and longer refractor would debut.
346:) to limit aberrations, so his telescope produced blurry and distorted images with a narrow field of view. Despite these flaws, the telescope was still good enough for Galileo to explore the sky. He used it to view
113:, then an eyepiece or instrumentation at the rear, where the telescope view comes to focus. Originally, telescopes had an objective of one element, but a century later, two and even three element lenses were made.
537:
In the late 19th century, the Swiss optician Pierre-Louis
Guinand developed a way to make higher quality glass blanks of greater than four inches (10 cm). He passed this technology to his apprentice
342:
objects about 30 times. Galileo had to work with the poor lens technology of the time, and found he had to use aperture stops to reduce the diameter of the objective lens (increase its
650:
In the 1900s a noted optics maker was Zeiss. An example of prime achievements of refractors, over 7 million people have been able to view through the 12-inch Zeiss refractor at
90:. Although large refracting telescopes were very popular in the second half of the 19th century, for most research purposes, the refracting telescope has been superseded by the
487:, a lens with multiple elements that helped solve problems with chromatic aberration and allowed shorter focal lengths. It was invented in 1733 by an English barrister named
1029:
657:
Achromats were popular in astronomy for making star catalogs, and they required less maintenance than metal mirrors. Some famous discoveries using achromats are the planet
819:
is dimmed by reflection and absorption when it crosses the air-glass interfaces and passes through the glass itself. Most of these problems are avoided or diminished in
706:
In the 18th century, Dollond, a popular maker of doublet telescopes, also made a triplet, although they were not really as popular as the two element telescopes.
672:
For example, the Nice
Observatory debuted with 77-centimeter (30.31 in) refractor, the largest at the time, but was surpassed within only a couple of years.
338:
Galileo's most powerful telescope, with a total length of 980 millimeters (39 in; 3 ft 3 in; 1.07 yd; 98 cm; 9.8 dm; 0.98 m),
2696:
639:
includes an objective by
Cauchoix. The Sheepshanks had a 6.7-inch (17 cm) wide lens, and was the biggest telescope at Greenwich for about twenty years.
918:
In 1861, the brightest star in the night sky, Sirius, was found to have smaller stellar companion using the 18 and half-inch
Dearborn refracting telescope.
846:
The "Große
Refraktor" a double telescope with a 80cm (31.5") and 50 cm (19.5") lenses, was used to discover calcium as an interstellar medium in 1904.
385:) after they passed through the eyepiece. This leads to an increase in the apparent angular size and is responsible for the perceived magnification.
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1285:
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The Yerkes Great refractor mounted at the 1893 World's Fair in
Chicago; the tallest, longest, and biggest aperture refractor up to that time.
495:
around 1758. The design overcame the need for very long focal lengths in refracting telescopes by using an objective made of two pieces of
2494:
1697:
was a Swiss who in the late 1700s came up with a breakthrough for making better quality and larger glass, and in time went on to teach
404:
Engraved illustration of a 46 m (150 ft) focal length
Keplerian astronomical refracting telescope built by Johannes Hevelius.
2075:
2048:
1067:
889:
The Galilean moons and many other moons of the solar system, were discovered with single-element objectives and aerial telescopes.
625:
377:) lens intercepts these rays and renders them parallel once more. Non-parallel rays of light from the object traveling at an angle
1925:
1735:
2388:
2021:
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Refracting telescopes were noted for their use in astronomy as well as for terrestrial viewing. Many early discoveries of the
834:
used a 6 centimetres (2.4 in) lens, launched into space in the late 1970s, an example of the use of refractors in space.
2153:
1935:
1856:
1677:
1502:
1436:
1307:
2361:
Morley, T. A. (February 1989). "A catalogue of ground-based astrometric observations of the Martian satellites, 1877-1982".
2245:
2588:
1249:
Albert Van Helden, Sven Dupré, Rob van Gent, The Origins of the Telescope, Amsterdam University Press, 2010, pages 3-4, 15
993:
In 1904, one of the discoveries made using Great Refractor of Potsdam (a double telescope with two doublets) was of the
690:
The Apochromatic lens usually comprises three elements that bring light of three different frequencies to a common focus
400:
2169:
1532:
1374:
1322:
778:
achromatic refractor is likely to show considerable color fringing (generally a purple halo around bright objects); an
753:, the largest achromatic refractor ever put into astronomical use (photo taken on 6 May 1921, as Einstein was visiting)
1351:, 1989, pg. 37, The University of Chicago Press, Albert van Helden tr., (History Dept. Rice University, Houston, TX),
646:
The power and general goodness of this telescope make it a most welcome addition to the instruments of the observatory
2504:
2205:
2121:
2085:
2058:
1745:
1716:
1701:
at Utzschinder's (Joseph von Utzschneider (1763-1840) glassworks, and eventually started his own optical glass works.
1409:
1356:
624:' in the 19th century saw large achromatic lenses, culminating with the largest achromatic refractor ever built, the
971:
The telescope used for the discovery was the 26-inch (66 cm) refractor (telescope with a lens) then located at
823:, which can be made in far larger apertures and which have all but replaced refractors for astronomical research.
717:
designs in the field of photography. The Cooke triplet can correct, with only three elements, for one wavelength,
2413:
1402:
The Mirror, the Window, and the Telescope: How Renaissance Linear Perspective Changed Our Vision of the Universe
392:) is a virtual image, located at infinity and is the same way up (i.e., non-inverted or upright) as the object.
1149:
1142:– the longest refracting telescope ever built (68 cm or 27 in × 21 m or 69 ft focal length)
2195:
726:
632:
592:
425:
built an unwieldy f/225 telescope with a 200-millimetre (8 in) objective and a 46-metre (150 ft)
1814:
642:
An 1840 report from the Observatory noted of the then-new Sheepshanks telescope with the Cauchoix doublet:
1126:
1122:
1063:
Examples of some of the largest achromatic refracting telescopes, over 60 cm (24 in) diameter.
865:
The use of refracting telescopic optics are ubiquitous in photography, and are also used in Earth orbit.
609:
1624:
713:, noted for being able to correct the Seidal aberrations. It is recognized as one of the most important
467:
Alvan Clark polishes the big Yerkes achromatic objective lens, over 1 meter (100 cm) across (1896).
2615:
2593:
941:
475:
This 12-inch (30 cm) refractor is mounted in a dome on a mount that matches the Earth's rotation.
2691:
1173:
1119:
refracting telescope - the largest refractor built by an individual, at Hanwell Community Observatory
17:
554:
The Greenwich 28-inch (71 cm) refractor is a popular tourist attraction in 21st century London.
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141:
116:
Refracting telescopes use technology that has often been applied to other optical devices, such as
2228:
1426:
574:
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1903:
1694:
1193:
1100:
1079:
998:
616:(dating to the late 1700s). A famous refractor was the "Trophy Telescope", presented at the 1851
444:
440:
434:
2438:
Barnard, E. E. (12 October 1892). "Discovery and observations of a fifth satellite to Jupiter".
2145:
975:. In 1893 the lens was remounted and put in a new dome, where it remains into the 21st century.
1178:
1139:
1094:
979:
636:
523:, and then the two pieces are assembled together. Achromatic lenses are corrected to bring two
31:
1899:
1706:
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1116:
964:
that began the day at noon, give the time of discovery as 11 August 14:40 and 17 August 16:06
1698:
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at the focal plane (to determine the angular size and/or distance between objects observed).
2571:
2374:
1787:
1761:
1589:
Tromp, R.M. (December 2015). "An adjustable electron achromat for cathode lens microscopy".
1555:
44:
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2003:
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8:
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2104:
Vasiljević, Darko (2002), "The Cooke triplet optimizations", in Vasiljević, Darko (ed.),
994:
896:
734:
654:
since its opening in 1935; this is the most people to have viewed through any telescope.
500:
240:
155:
2451:
2321:
2284:
2007:
1885:
206:
is used to gather more light than the human eye is able to collect on its own, focus it
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1952:
Astronomical Observations, Made at the Royal Observatory at Greenwich, in the year 1838
1512:
1155:
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1073:
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907:
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714:
530:
Chester More Hall is noted as having made the first twin color corrected lens in 1730.
488:
481:
The next major step in the evolution of refracting telescopes was the invention of the
190:
171:
67:
1228:
1021:
was discovered by looking at photographs (i.e. 'plates' in astronomy vernacular) in a
2500:
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990:. It was discovered by direct visual observation with the doublet-lens refractor.
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359:
321:
163:
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129:
84:
1848:
1669:
1025:
taken with a refracting telescope, an astrograph with a 3 element 13-inch lens.
102:
is calculated by dividing the focal length of the objective lens by that of the
766:
355:
244:
125:
1048:
745:
463:
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222:
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110:
99:
63:
2599:
Angular and Linear Fields of View of Galilean Telescopes and Telemicroscopes
2177:
2106:
Classical and Evolutionary Algorithms in the Optimization of Optical Systems
2077:
Classical and Evolutionary Algorithms in the Optimization of Optical Systems
2641:
1610:
972:
903:
859:
492:
426:
1843:. Astrophysics and Space Science Library. Vol. 397. pp. 77–125.
842:
215:
508:
343:
248:
189:
All refracting telescopes use the same principles. The combination of an
151:
87:
79:). The refracting telescope design was originally used in spyglasses and
550:
369:) would be brought to a focus in the focal plane of the objective lens (
2476:
A Brief Account of the Lick Observatory of the University of California
1208:
1168:
1053:
933:
812:
804:
681:
524:
418:
232:
211:
162:
unsuccessfully tried to patent one. News of the patent spread fast and
117:
1977:"Griffith Observatory - Southern California's gateway to the cosmos!"
1145:
United States Naval Observatory refractor, (66 cm or 26 in)
831:
827:
520:
121:
80:
75:
72:
273:
2496:
The Cosmic Connection: How Astronomical Events Impact Life on Earth
2459:
2334:
Hall, A. (January 1878). "Observations of the Satellites of Mars".
2293:
2268:
1976:
1660:
English, Neil (2011). "The Refracting Telescope: A Brief History".
789:
770:
699:
200:
103:
95:
1872:
King, H. C. (January 1949). "The optical work of Charles Tulley".
1347:
Sidereus Nuncius or The Sidereal Messenger, 1610, Galileo Galilei
1006:
1002:
793:
658:
109:
Refracting telescopes typically have a lens at the front, then a
922:
comparison to modern instruments. Noted discoveries include the
978:
Jupiter's moon Amalthea was discovered on 9 September 1892, by
167:
170:
in the month of May 1609, heard of the invention, constructed
30:"Keplerian telescope" redirects here. Not to be confused with
1664:. Patrick Moore's Practical Astronomy Series. pp. 3–20.
1379:
Museo Galileo: Institute and Museum of the History of Science
1327:
Museo Galileo: Institute and Museum of the History of Science
1030:
Timeline of discovery of Solar System planets and their moons
1018:
803:
There is a further problem of glass defects, striae or small
797:
686:
496:
236:
150:. The first record of a refracting telescope appeared in the
1035:
906:, was discovered on March 25, 1655, by the Dutch astronomer
876:
351:
182:
2636:
2572:"John Wall refractor | Hanwell Community Observatory"
1560:. New York: McGraw-Hill – via The Project Gutenberg.
1535:. Museo Galileo - Istituto e Museo di Storia della Scienza
1070:(1.25 m or 49 in) – dismantled after exhibition
957:
491:, although it was independently invented and patented by
433:" were constructed). The design also allows for use of a
39:
880:
Touristic telescope pointed to Matterhorn in Switzerland
2273:
Publications of the Astronomical Society of the Pacific
527:(typically red and blue) into focus in the same plane.
612:(71 cm). An example of an older refractor is the
2613:
1431:. Chicago: University of Chicago Press. p. 153.
1259:
Science, Lauren Cox 2017-12-21T03:30:00Z; Astronomy.
174:, and applied it to making astronomical discoveries.
1839:
Lequeux, James (2013). "The Observatory: At Last!".
1103:(80 cm (31 in), + 50 cm (20 in))
1097:(83 cm (33 in), + 62 cm (24 in))
788:
In very large apertures, there is also a problem of
604:
Some famous 19th century doublet refractors are the
1492:
2137:
1404:. Ithaca: Cornell University Press. p. 159.
2673:
2472:
2389:"Telescope: Naval Observatory 26-inch Refractor"
2200:. Cambridge University Press. pp. 220–221.
1841:Le Verrier—Magnificent and Detestable Astronomer
1001:determined from observations of the binary star
899:of Jupiter in 1610 with a refracting telescope.
837:
807:trapped within the glass. In addition, glass is
2466:
1994:Hollis, H. P. (June 1914). "Large telescopes".
1564:
1298:Stephen G. Lipson, Ariel Lipson, Henry Lipson,
1189:List of largest optical telescopes historically
749:The 102 centimetres (40 in) refractor, at
545:Noted lens makers of the 19th century include:
447:with a 19 cm (7.5″) single-element lens.
177:
2189:
2187:
2135:
381:to the optical axis travel at a larger angle (
365:Parallel rays of light from a distant object (
43:A 200 mm diameter refracting telescope at the
1923:
1184:List of largest optical refracting telescopes
2697:Science and technology in the Dutch Republic
2363:Astronomy and Astrophysics Supplement Series
2193:
1533:"Galileo's telescope - Chromatic aberration"
1258:
854:Astronaut trains with camera with large lens
709:One of the famous triplet objectives is the
2184:
1924:Tombaugh, Clyde W.; Moore, Patrick (2017).
1284:: CS1 maint: numeric names: authors list (
740:
247:; while those not parallel converge upon a
2414:"The 26-inch "Great Equatorial" Refractor"
2354:
2103:
2073:
1517:: CS1 maint: location missing publisher (
1129:, (71 cm or 28 in) aperture lens
984:36 inches (91 cm) refractor telescope
960:(contemporary sources, using the pre-1925
785:16 achromat has much less color fringing.
675:
2292:
2080:. Springer Science & Business Media.
1815:"The Glassmaker Who Sparked Astrophysics"
1662:Choosing and Using a Refracting Telescope
1572:"Largest optical telescopes of the world"
1036:List of the largest refracting telescopes
291:– Magnified virtual image from eyepiece;
2266:
1987:
1812:
1733:
1477:
1399:
1068:Great Paris Exhibition Telescope of 1900
1047:
1039:
875:
849:
841:
744:
685:
626:Great Paris Exhibition Telescope of 1900
549:
519:. Each side of each piece is ground and
470:
462:
450:
399:
272:
231:The objective in a refracting telescope
181:
154:about 1608, when a spectacle maker from
38:
2437:
2269:"The Beginning of the Astronomical Day"
1838:
1659:
14:
2674:
2492:
2360:
2227:. Cambridge. p. 4. Archived from
2162:
2046:
1993:
1323:"Galileo's telescope - The instrument"
395:
2488:
2486:
2099:
2097:
2074:Vasiljevic, Darko (6 December 2012).
1971:
1969:
1927:Out of the Darkness: The Planet Pluto
1737:History of Astronomy: An Encyclopedia
1655:
1653:
1651:
1649:
1647:
1645:
1588:
1424:
1005:in Orion, that there was the element
278:Optical diagram of Galilean telescope
266:
146:Refractors were the earliest type of
70:to form an image (also referred to a
2333:
1871:
1704:
1553:
1375:"Galileo's telescope - How it works"
1369:
1367:
1365:
1317:
1315:
2609:Introduction to Galileo's Telescope
2479:. The University Press. p. 7–.
1944:
1832:
1629:National Museum of American History
862:were made with singlet refractors.
24:
2483:
2094:
2022:"Starizona's Guide to CCD Imaging"
1966:
1762:"Brashear House Historical Marker"
1642:
1493:Tunnacliffe, AH; Hirst JG (1996).
25:
2708:
2582:
2267:Campbell, W. W. (December 1918).
2108:, Springer US, pp. 187–211,
1813:Ferguson, Kitty (20 March 2014).
1705:King, Henry C. (1 January 2003).
1497:. Kent, England. pp. 233–7.
1362:
1312:
1252:
940:on 12 August 1877 at about 07:48
2659:
2647:
2635:
2623:
2493:Kanipe, Jeff (27 January 2011).
2197:The Cambridge Planetary Handbook
1792:Canvases, Carats and Curiosities
757:Refractors suffer from residual
210:, and present the viewer with a
83:telescopes but is also used for
2564:
2538:
2513:
2431:
2418:United States Naval Observatory
2406:
2381:
2327:
2301:
2260:
2238:
2214:
2129:
2067:
2040:
2024:. Starizona.com. Archived from
2014:
1930:. Stackpole Books. p. 56.
1917:
1892:
1865:
1806:
1780:
1754:
1734:Lankford, John (7 March 2013).
1727:
1686:
1617:
1582:
1547:
1525:
1486:
1482:. Vol. First Part. Auctor.
1471:
1445:
1028:For a chronological guide, see
698:telescopes contain elements of
299:– Virtual exit pupil diameter;
1603:10.1016/j.ultramic.2015.03.001
1418:
1393:
1341:
1302:, Cambridge University Press,
1292:
1243:
1221:
1152:(62.5 cm or 24.6 in)
1150:National Observatory of Athens
1115:(76.20 cm or 30 in)
1056:(27 in) refractor at the
443:built an aerial telescope for
13:
1:
2550:National Air and Space Museum
1261:"Who Invented the Telescope?"
1214:
1076:(101.6 cm or 40 in)
1058:Vienna University Observatory
926:and a fifth moon of Jupiter,
838:Applications and achievements
635:an 1838 instrument named the
373:). The (diverging) eyepiece (
325:
287:– Real image from objective;
2589:nasa.gov – Build a Telescope
2250:Astronomy Picture of the Day
2114:10.1007/978-1-4615-1051-2_13
1708:The History of the Telescope
1136:, (69 cm or 27 in)
633:Royal Observatory, Greenwich
429:, and even longer tubeless "
243:light rays to converge at a
178:Refracting telescope designs
135:
7:
2594:Making a Galilean Telescope
2316:: 181–185. September 1877.
2047:Kidger, Michael J. (2002).
1849:10.1007/978-1-4614-5565-3_4
1670:10.1007/978-1-4419-6403-8_1
1478:Hevelius, Johannes (1673).
1300:Optical Physics 4th Edition
1162:
1127:Royal Greenwich Observatory
1080:Swedish 1-m Solar Telescope
620:in London. The era of the '
610:Greenwich 28 inch refractor
608:(91 cm/36 in) and the
295:– Entrance pupil diameter;
10:
2713:
2050:Fundamental Optical Design
1158:(61 cm or 24 in)
1109:(77 cm or 30 in)
1088:(91 cm or 36 in)
1082:(98 cm or 39 in)
1027:
1009:in the intervening space.
948:on 18 August 1877, at the
902:The planet Saturn's moon,
769:more than longer ones. An
679:
454:
139:
29:
2473:Lick Observatory (1894).
2336:Astronomische Nachrichten
1954:. Clarendon Press. 1840.
239:. This refraction causes
27:Type of optical telescope
2440:The Astronomical Journal
2348:10.1002/asna.18780910103
1788:"Cauchoix, Robert-Aglae"
1457:Intellectual Mathematics
1400:Edgerton, S. Y. (2009).
1229:"Telescope Calculations"
1148:Newall refractor at the
741:Technical considerations
356:largest moons of Jupiter
142:History of the telescope
2546:"Pluto Discovery Plate"
2393:amazing-space.stsci.edu
2375:1989A&AS...77..209M
2144:. Mcgraw-hill. p.
2136:Stan Gibilisco (2002).
1960:2027/njp.32101074839562
1904:Royal Museums Greenwich
1900:"Sheepshanks telescope"
1711:. Courier Corporation.
1194:List of telescope types
1179:Catadioptric telescopes
1123:28-inch Grubb Refractor
1101:Potsdam Great Refractor
962:astronomical convention
765:. This affects shorter
695:Apochromatic refractors
676:Apochromatic refractors
445:Royal Society of London
311:– Virtual exit pupil –
2252:. NASA. Archived from
2222:"Lifting Titan's Veil"
1174:Baden-Powell's unilens
1140:Archenhold Observatory
1095:Meudon Great Refractor
1060:
1045:
980:Edward Emerson Barnard
881:
855:
847:
754:
691:
648:
555:
476:
468:
405:
315:
186:
94:, which allows larger
47:
32:Kepler space telescope
2604:Refracting telescopes
2521:"The Pluto Telescope"
2194:Bakich M. E. (2000).
2180:on 11 September 2016.
1699:Joseph von Fraunhofer
1051:
1043:
879:
853:
845:
821:reflecting telescopes
748:
689:
644:
637:Sheepshanks telescope
553:
540:Joseph von Fraunhofer
474:
466:
451:Achromatic refractors
403:
331:is commonly called a
276:
257:refracting telescopes
185:
166:, happening to be in
42:
2499:. Prometheus Books.
2234:on 22 February 2005.
1981:Griffith Observatory
1766:ExplorePaHistory.com
1695:Pierre-Louis Guinand
1554:Bell, Louis (1922).
1199:Reflecting telescope
966:Washington mean time
950:US Naval Observatory
763:spherical aberration
719:spherical aberration
652:Griffith Observatory
614:Shuckburgh telescope
606:James Lick telescope
517:spherical aberration
457:Achromatic telescope
172:a version of his own
92:reflecting telescope
52:refracting telescope
2452:1892AJ.....12...81B
2322:1877Obs.....1..181.
2285:1918PASP...30..358C
2140:Physics Demystified
2008:1914Obs....37..245H
1886:1949PA.....57...74K
1625:"Dollond Telescope"
1576:www.stjarnhimlen.se
1132:Great Refractor of
995:interstellar medium
897:Galilean satellites
826:The ISS-WAC on the
410:Keplerian telescope
396:Keplerian telescope
2525:Lowell Observatory
2028:on 17 October 2013
1425:Drake, S. (1978).
1156:Lowell Observatory
1134:Vienna Observatory
1074:Yerkes Observatory
1061:
1046:
999:Professor Hartmann
908:Christiaan Huygens
895:'s discovered the
882:
856:
848:
755:
751:Yerkes Observatory
692:
556:
489:Chester Moore Hall
477:
469:
406:
333:Galilean telescope
316:
303:– Objective lens;
283:– Distant object;
267:Galilean telescope
187:
48:
45:Poznań Observatory
2256:on 27 March 2005.
2155:978-0-07-138201-4
1937:978-0-8117-6664-7
1874:Popular Astronomy
1858:978-1-4614-5564-6
1679:978-1-4419-6402-1
1504:978-0-900099-15-1
1480:Machina Coelestis
1453:"Phases of Venus"
1438:978-0-226-16226-3
1308:978-0-521-49345-1
1092:Paris Observatory
997:. The astronomer
956:, at about 09:14
431:aerial telescopes
423:Johannes Hevelius
388:The final image (
199:and some type of
148:optical telescope
60:optical telescope
16:(Redirected from
2704:
2692:Dutch inventions
2664:
2663:
2662:
2652:
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2650:
2640:
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2628:
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2257:
2242:
2236:
2235:
2233:
2226:
2218:
2212:
2211:
2191:
2182:
2181:
2176:. Archived from
2166:
2160:
2159:
2143:
2133:
2127:
2126:
2101:
2092:
2091:
2071:
2065:
2064:
2044:
2038:
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2018:
2012:
2011:
1991:
1985:
1984:
1973:
1964:
1963:
1948:
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1941:
1921:
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1910:
1896:
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1551:
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1529:
1523:
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1397:
1391:
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1388:
1386:
1371:
1360:
1345:
1339:
1338:
1336:
1334:
1319:
1310:
1296:
1290:
1289:
1283:
1275:
1273:
1271:
1256:
1250:
1247:
1241:
1240:
1238:
1236:
1231:. Northern Stars
1225:
1107:Nice Observatory
1086:Lick Observatory
1023:blink comparator
988:Lick Observatory
954:Washington, D.C.
784:
782:
776:
774:
622:great refractors
618:Great Exhibition
330:
327:
313:Telescope equals
307:– Eyepiece lens
98:. A refractor's
21:
2712:
2711:
2707:
2706:
2705:
2703:
2702:
2701:
2687:Telescope types
2672:
2671:
2670:
2660:
2658:
2648:
2646:
2634:
2624:
2622:
2614:
2585:
2580:
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2555:
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2544:
2543:
2539:
2529:
2527:
2519:
2518:
2514:
2507:
2491:
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2436:
2432:
2422:
2420:
2412:
2411:
2407:
2397:
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2382:
2359:
2355:
2332:
2328:
2310:The Observatory
2307:
2306:
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2265:
2261:
2244:
2243:
2239:
2231:
2224:
2220:
2219:
2215:
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2192:
2185:
2174:astronautix.com
2168:
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2156:
2134:
2130:
2124:
2102:
2095:
2088:
2072:
2068:
2061:
2045:
2041:
2031:
2029:
2020:
2019:
2015:
1996:The Observatory
1992:
1988:
1975:
1974:
1967:
1950:
1949:
1945:
1938:
1922:
1918:
1908:
1906:
1898:
1897:
1893:
1870:
1866:
1859:
1837:
1833:
1823:
1821:
1811:
1807:
1797:
1795:
1794:. 31 March 2015
1786:
1785:
1781:
1771:
1769:
1760:
1759:
1755:
1748:
1732:
1728:
1719:
1691:
1687:
1680:
1658:
1643:
1633:
1631:
1623:
1622:
1618:
1591:Ultramicroscopy
1587:
1583:
1570:
1569:
1565:
1552:
1548:
1538:
1536:
1531:
1530:
1526:
1510:
1509:
1505:
1491:
1487:
1476:
1472:
1462:
1460:
1451:
1450:
1446:
1439:
1428:Galileo at Work
1423:
1419:
1412:
1398:
1394:
1384:
1382:
1373:
1372:
1363:
1346:
1342:
1332:
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1297:
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1257:
1253:
1248:
1244:
1234:
1232:
1227:
1226:
1222:
1217:
1165:
1038:
1033:
968:respectively).
893:Galileo Galilei
840:
780:
779:
772:
771:
743:
731:field curvature
684:
678:
570:Chance Brothers
558:
557:
499:with different
484:achromatic lens
479:
478:
459:
453:
414:Johannes Kepler
398:
360:phases of Venus
328:
322:Galileo Galilei
318:
317:
269:
180:
164:Galileo Galilei
160:Hans Lippershey
144:
138:
130:long-focus lens
58:) is a type of
54:(also called a
35:
28:
23:
22:
15:
12:
11:
5:
2710:
2700:
2699:
2694:
2689:
2684:
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2668:
2656:
2644:
2632:
2612:
2611:
2606:
2601:
2596:
2591:
2584:
2583:External links
2581:
2578:
2577:
2563:
2552:. 24 June 2016
2537:
2512:
2505:
2482:
2465:
2460:10.1086/101715
2430:
2405:
2380:
2369:(2): 209–226.
2353:
2326:
2300:
2294:10.1086/122784
2259:
2237:
2213:
2206:
2183:
2161:
2154:
2128:
2122:
2093:
2086:
2066:
2059:
2053:. SPIE Press.
2039:
2013:
1986:
1965:
1943:
1936:
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886:
839:
836:
792:, a result of
742:
739:
680:Main article:
677:
674:
602:
601:
598:
595:
593:Henry Brothers
590:
585:
582:
577:
572:
567:
564:
548:
547:
461:
460:
455:Main article:
452:
449:
412:, invented by
397:
394:
271:
270:
268:
265:
179:
176:
140:Main article:
137:
134:
126:telephoto lens
26:
9:
6:
4:
3:
2:
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2508:
2506:9781591028826
2502:
2498:
2497:
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2477:
2469:
2461:
2457:
2453:
2449:
2446:(11): 81–85.
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2207:9780521632805
2203:
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2125:
2123:9781461510512
2119:
2115:
2111:
2107:
2100:
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2089:
2087:9781461510512
2083:
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2078:
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2060:9780819439154
2056:
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2005:
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1793:
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1749:
1747:9781136508349
1743:
1740:. Routledge.
1739:
1738:
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1720:
1718:9780486432656
1714:
1710:
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1558:
1557:The Telescope
1550:
1534:
1528:
1520:
1514:
1506:
1500:
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1474:
1459:. 2 June 2019
1458:
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1411:9780801474804
1407:
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1357:0-226-27903-0
1354:
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1204:Star diagonal
1202:
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951:
947:
943:
939:
935:
931:
929:
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924:Moons of Mars
919:
913:
912:
911:
909:
905:
900:
898:
894:
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883:
878:
874:
870:
866:
863:
861:
852:
844:
835:
833:
829:
824:
822:
818:
817:visible light
814:
810:
806:
801:
799:
795:
791:
786:
777:
768:
764:
760:
752:
747:
738:
736:
732:
728:
724:
720:
716:
712:
711:Cooke triplet
707:
704:
701:
696:
688:
683:
673:
670:
666:
664:
663:Moons of Mars
660:
655:
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647:
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629:
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623:
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541:
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531:
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522:
518:
514:
511:', to reduce
510:
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494:
490:
486:
485:
473:
465:
458:
448:
446:
442:
438:
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279:
275:
264:
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229:
227:
224:
223:virtual image
221:
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209:
205:
202:
198:
195:
192:
184:
175:
173:
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161:
157:
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149:
143:
133:
131:
127:
123:
119:
114:
112:
107:
105:
101:
100:magnification
97:
93:
89:
88:camera lenses
86:
82:
78:
77:
74:
69:
65:
61:
57:
53:
46:
41:
37:
33:
19:
2666:Solar System
2566:
2554:. Retrieved
2549:
2540:
2528:. Retrieved
2524:
2515:
2495:
2475:
2468:
2443:
2439:
2433:
2421:. Retrieved
2417:
2408:
2396:. Retrieved
2392:
2383:
2366:
2362:
2356:
2342:(1): 11–14.
2339:
2335:
2329:
2313:
2309:
2303:
2279:(178): 358.
2276:
2272:
2262:
2254:the original
2249:
2240:
2229:the original
2216:
2196:
2178:the original
2173:
2164:
2139:
2131:
2105:
2076:
2069:
2049:
2042:
2030:. Retrieved
2026:the original
2016:
1999:
1995:
1989:
1980:
1951:
1946:
1926:
1919:
1907:. Retrieved
1894:
1877:
1873:
1867:
1840:
1834:
1822:. Retrieved
1818:
1808:
1796:. Retrieved
1791:
1782:
1770:. Retrieved
1765:
1756:
1736:
1729:
1707:
1688:
1661:
1632:. Retrieved
1628:
1619:
1594:
1590:
1584:
1575:
1566:
1556:
1549:
1537:. Retrieved
1527:
1494:
1488:
1479:
1473:
1463:27 September
1461:. Retrieved
1456:
1447:
1427:
1420:
1401:
1395:
1385:27 September
1383:. Retrieved
1378:
1348:
1343:
1333:27 September
1331:. Retrieved
1326:
1299:
1294:
1268:. Retrieved
1264:
1254:
1245:
1233:. Retrieved
1223:
1062:
1052:The 68
1016:
992:
977:
973:Foggy Bottom
970:
932:
920:
917:
901:
891:
888:
871:
867:
864:
860:Solar System
857:
825:
802:
790:lens sagging
787:
767:focal ratios
756:
708:
705:
694:
693:
671:
667:
656:
649:
645:
641:
630:
603:
544:
536:
532:
529:
493:John Dollond
482:
480:
439:
427:focal length
409:
407:
389:
387:
382:
378:
374:
370:
366:
364:
337:
332:
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2654:Outer space
2556:19 November
2530:19 November
2002:: 245–252.
1909:27 February
1772:16 November
1768:. WITF, Inc
1634:19 November
1597:: 497–502.
1235:20 December
936:discovered
815:, and even
813:wavelengths
811:to certain
805:air bubbles
727:astigmatism
562:Alvan Clark
525:wavelengths
509:flint glass
354:, the four
344:focal ratio
329: 1609
320:The design
249:focal plane
245:focal point
152:Netherlands
122:zoom lenses
2682:Telescopes
2676:Categories
2423:29 October
2398:29 October
2032:17 October
1824:26 October
1798:26 October
1270:26 October
1215:References
1209:Heliometer
1169:Astrograph
982:using the
934:Asaph Hall
796:deforming
735:distortion
703:aperture.
682:Apochromat
580:Fraunhofer
501:dispersion
435:micrometer
419:eye relief
383:α2 > α1
371:F′ L1 / y′
358:, and the
261:refractors
156:Middelburg
118:binoculars
85:long-focus
2630:Astronomy
2308:"Notes".
2170:"Voyager"
1513:cite book
1265:Space.com
1113:John Wall
828:Voyager 1
759:chromatic
715:objective
597:Lerebours
513:chromatic
340:magnified
235:or bends
220:magnified
191:objective
136:Invention
111:long tube
96:apertures
76:telescope
68:objective
56:refractor
18:Refractor
1819:Nautilus
1611:25825026
1280:cite web
1163:See also
1013:Triplets
928:Amalthea
914:Doublets
885:Singlets
700:fluorite
661:and the
575:Cauchoix
566:Brashear
521:polished
241:parallel
233:refracts
212:brighter
201:eyepiece
104:eyepiece
73:dioptric
2616:Portals
2448:Bibcode
2371:Bibcode
2318:Bibcode
2281:Bibcode
2246:"Titan"
2004:Bibcode
1882:Bibcode
1539:5 March
1117:dialyte
1017:Planet
1007:calcium
1003:Mintaka
794:gravity
659:Neptune
631:In the
584:Gautier
507:' and '
441:Huygens
350:on the
348:craters
216:clearer
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1495:Optics
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1355:
1349:et al.
1329:. 2008
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946:Phobos
938:Deimos
809:opaque
733:, and
600:Tulley
218:, and
168:Venice
158:named
2642:Stars
2232:(PDF)
2225:(PDF)
1019:Pluto
904:Titan
798:glass
588:Grubb
505:crown
497:glass
324:used
237:light
2558:2019
2532:2019
2501:ISBN
2425:2018
2400:2018
2202:ISBN
2150:ISBN
2118:ISBN
2082:ISBN
2055:ISBN
2034:2013
1932:ISBN
1911:2014
1853:ISBN
1826:2019
1800:2019
1774:2021
1742:ISBN
1713:ISBN
1674:ISBN
1636:2019
1607:PMID
1541:2012
1519:link
1499:ISBN
1465:2020
1433:ISBN
1406:ISBN
1387:2020
1353:ISBN
1335:2020
1304:ISBN
1286:link
1272:2019
1237:2013
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515:and
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194:lens
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2456:doi
2344:doi
2289:doi
2146:532
2110:doi
1956:hdl
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