document_title: Timeline of European exploration

question_text: who was the first european to discover the mississippi river

text: Timeline of European exploration

text: 15th century[edit]

text:
1418 – João Gonçalves Zarco and Tristão Vaz Teixeira discover Porto Santo.[1]
1419 – Gonçalves and Vaz discover Madeira.[1]
1427 – Diogo de Silves discovers the Azores.[1]
1434 – Gil Eanes passes Cabo de Não and rounds Cape Bojador.[2]
1443 – Nuno Tristão passes Cape Blanco.[1]
1444 – Dinis Dias reaches the mouth of the Senegal River.[3]
1446 – The Portuguese reach Cape Verde and the Gambia River.[3]
1456 – Alvise Cadamosto and Diogo Gomes explored the Cape Verde Islands.[1]
1460 – Pêro de Sintra reaches Sierra Leone.[1]
1470 – Cape Palmas is passed.[3]
1472 – Fernão do Pó discovers Bioko.[4]
1473 – Lopo Gonçalves is the first to cross the equator.[3][4]
1474–75 – Ruy de Sequeira discovers São Tomé and Príncipe.[4]
1482 – Diogo Cão reaches the Congo River, where he erects a "padrão" (pillar of stone).[4]
1485–86 – Cão reaches Cape Cross, where he erects his last padrão.[4]
1487–92 – Pêro da Covilhã travels to Arabia, down to the mouth of the Red Sea, eastward by sail to the Malabar Coast (visiting Calicut and Goa); later sails down the east coast of Africa (visiting the trading stations of Mombasa, Zanzibar, and Sofala); on his return he visits Mecca and Medina before reaching Ethiopia in search of the mythical Prester John.[5]
1488 – Bartolomeu Dias rounds the "Cape of Storms" (Cape of Good Hope).[4]
1492 – Christopher Columbus discovers the Bahamas, Cuba, and "Española" (Hispaniola).[6]
1493–94 – Columbus discovers Dominica and Guadeloupe, among other islands of the Lesser Antilles; also discovers Puerto Rico and Jamaica.[6]
1497 – John Cabot discovers Newfoundland.[7]
1497–98 – Vasco da Gama sails to India and back.[3]
1498 – Columbus discovers the mainland of South America.[6]
1499 – Alonso de Ojeda explores the South American mainland from about Cayenne (in modern French Guiana) to Cabo de la Vela (in modern Colombia), discovering the mouths of the Orinoco and entering Lake Maracaibo.[2]
1499 – Amerigo Vespucci discovers the mouth of the Amazon River and reaches 6°S, in present-day northern Brazil.[8]
1499 – João Fernandes Lavrador, together with Pêro de Barcelos, sight Labrador.[9]
1499 – Gaspar and Miguel Corte-Real reach and map Greenland.[10]

text: 16th century[edit]

text:
1500 – Vicente Yáñez Pinzón reaches the northeast coast of what today is Brazil at a cape he names "Santa Maria de la Consolación" (Cabo de Santo Agostinho) and sails fifty miles up a river he names the "Marañón" (Amazon).[2]
1500 – Pedro Álvares Cabral makes the "official" discovery of Brazil,[2] leading the first expedition that united Europe, America, Africa, and Asia.[11][12]
1500 – João Fernandes reaches Cape Farewell, Greenland ("Terra do Lavrador", or Land of the Husbandman).[7]
1500–02 – Gaspar and Miguel Corte Real discover and name the coasts of "Terra Verde" (likely Newfoundland) and Labrador.[7][10]
1500-01 – Diogo Dias discovers Madagascar and reaches the gate of the Red Sea, the Bab-el-Mandeb Strait.[2]
1500 – Rodrigo de Bastidas explores the Colombian coast from Cabo de la Vela to the Gulf of Urabá.[2]
1501-02 – Gonçalo Coelho discovers "Rio de Janeiro" (Guanabara Bay).[2]
1502–03 – Columbus explores the North American mainland from Guanaja off modern Honduras to the present-day border of Panama and Colombia.[2][6]
1505 – Juan de Bermúdez discovers Bermuda.[2]
1506 – Lourenço de Almeida reaches the Maldives and Sri Lanka.[13]
1506 – Tristão da Cunha discovers the island of Tristan da Cunha.[citation needed]
1509 – Diogo Lopes de Sequeira reaches Sumatra and Malacca.[14]
1511 – Duarte Fernandes leads a diplomatic mission to Ayutthaya Kingdom (Siam or Thailand).[15]
1511 – Rui Nunes da Cunha leads a diplomatic mission to Pegu (Burma or Myanmar).[15][16]
1511–12 – João de Lisboa and Estevão de Fróis discover the "Cape of Santa Maria" (Punta Del Este) in the River Plate, exploring its estuary, and traveling as far south as the Gulf of San Matias at 42ºS, in present-day Uruguay and Argentina (penetrating 300 km (186 mi) "around the Gulf").[17][18]
1511–12 – António de Abreu sails through the Strait of Malacca, between Sumatra and Bangka, and along the coasts of Java, Bali, Lombok, Sumbawa, and Flores to the "Spice Islands" (Maluku).[19]
1513 – Jorge Álvares lands off the coast of China, on Nei Lingding Island at the Pearl River Delta.[1]
1513 – Vasco Núñez de Balboa crosses the Isthmus of Panama and reaches the Bay of San Miguel, discovering the "Mar del Sur" (Pacific Ocean).[2]
1513 – Juan Ponce de León discovers "La Florida" (Florida) and the Yucatan.[2]
1514–15 – António Fernandes reaches present-day Zimbabwe.[20]
1515 – Gonzalo de Badajoz crosses the Isthmus of Panama at the site of Nombre de Dios, reaching as far as the interior of the Azuero Peninsula.[21]
1516 – Juan Díaz de Solís explores the River Plate estuary and names it "La Mar Dulce" ("The Fresh-Water Sea").[2]
1516 – Portuguese traders land in Da Nang, Champa, naming it Cochinchina (modern Vietnam).[22][23]
1518 – Lourenço Gomes reaches Borneo.[24]
1518 – Juan de Grijalva explores the Mexican coast from "Patouchan" (Champotón) to just north of the Pánuco River.[2]
1519 – Hernán Cortés travels from Villa Rica de la Vera Cruz to the Aztec capital of Tenochtitlan on Lake Texcoco.[25]
1519 – Alonzo Alvarez de Pineda sails around the Gulf of Mexico to the Pánuco, proving its insularity; also discovers the "Father of Waters" (the Mississippi).[2]
1519 – Gaspar de Espinosa sails west along the west coasts of modern Panama and Costa Rica as far as the Gulf of Nicoya.[21]
1519–22 – Ferdinand Magellan's expedition completes the first circumnavigation of the globe, exploring the coast of Patagonia and discovering and traversing the Strait of Magellan.[26]
1520–21 – João Alvares Fagundes explores Burgeo and Saint Pierre and Miquelon in Newfoundland, and Nova Scotia.[27][28]
1521 – Francisco Gordillo and Pedro de Quexos find the mouth of a river they name "Rio de San Juan Bautista" (perhaps Winyah Bay at the mouth of the Pee Dee River in modern South Carolina).[29]
1521 – Cristóvão Jacques explores the Plate River and discovers the Parana River, entering it for about 23 leagues (around 140 km), to near the present city of Rosario.[30]
1522 – Gil González Dávila explores inland from the Gulf of Nicoya, discovering Lake Nicaragua, while his pilot Andrés Niño explores along the coast to the west, discovering the Gulf of Fonseca and perhaps reaching as far as the southwestern coast of modern Guatemala.[21]
1524 – Giovanni da Verrazzano explores the eastern seaboard of the present United States from about Cape Fear to Maine; discovers the mouth of the Hudson River.[7]
c. 1524 – Aleixo Garcia travels westward from Santa Catarina, across the Paraná (perhaps sighting Iguazu Falls) to the Paraguay near the site of Asunción, then across the Gran Chaco to the Andes and the Inca frontier, somewhere between Mizque and Tomina in modern Bolivia.[31]
1524–25 – Francisco Pizarro and Diego de Almagro explore from Punta Piña (7° 56’ N) on the southern coast of Panama to the San Juan River (4° N), on the west coast of Colombia.[32]
1525 – Estêvão Gomes probes Penobscot Bay, Maine.[29]
1525 – The Portuguese reach "Celebes" (Sulawesi).[33]
1525 – Diogo da Rocha and Gomes de Sequeira discover the Caroline Islands.[34]
1526 – Alonso de Salazar discovers the Marshall Islands (Bokak Atoll).[35]
1526–28 – Pizarro and his pilot Bartolomé Ruiz explore the west coast of South America from the San Juan River south to the Santa River (about 9° S), becoming the first to sight the coasts of Ecuador and Peru.[32]
1526–27 – Jorge de Menezes discovers New Guinea.[36]
1527–28 – Sebastian Cabot explores several hundred miles up the Paraná River, past its confluence with the Paraguay.[2]
1528 – Diogo Rodrigues explores the Mascarene Islands (which he names after Pedro Mascarenhas), naming the islands of Réunion, Mauritius, and Rodrigues.[37]
1528–36 – Álvar Núñez Cabeza de Vaca and three others are the only survivors of a group of several hundred colonists who travel from the coast of western Florida to the Rio Sinaloa in northern Mexico, where they encounter Spanish slavers.[38]
1531 – Diego de Ordaz ascends the Orinoco to the Atures rapids, just past its confluence with the Meta.[31]
1532–33 – Pizarro explores and conquers inland to Cajamarca and Cuzco.[31]
1533 – Fortún Ximénez finds the tip of Baja California.[39]
1534 – Jacques Cartier explores the Gulf of St. Lawrence, discovering Anticosti Island and Prince Edward Island.[7]
1535 – Fray Tomás de Berlanga discovers the Galapagos Islands.[40]
1535 – Cartier ascends "La Grande Rivière" or "La Rivière de Hochelaga" (the St. Lawrence River) to the village of Hochelaga (present-day Montreal).[7]
1535–37 – Diego de Almagro leads en expedition from Cuzco to the south, taking the Inca highway to the southwest shore of Lake Titicaca, through the altiplano and the Salta valley to Copiapó; a detachment continues south to the Maule River. Almagro takes the coastal route back, through the Atacama Desert.[31]
1539 – Francisco de Ulloa sails to the head of the Gulf of California and around Baja California to Cedros Island, establishing that Baja is a peninsula.[39]
1539–43 – Hernando de Soto's expedition explores much of the modern American South, becoming the first to cross the Appalachians (over the Blue Ridge Mountains) and the Mississippi.[2][29]
1540–42 – Francisco Vásquez de Coronado searches for the mythical Seven Cities of Cibola, only to find villages of mud and thatch. He sends out smaller parties, one of which, under García López de Cárdenas, discovers the Grand Canyon; another finds a city of gold called Quivira (in modern Kansas), which Coronado later visits — although he finds no gold.[29]
1540 – Hernando de Alarcón ascends the Colorado River to the confluence of the Gila River (near present-day Yuma, Arizona).[39]
1541–42 – Francisco de Orellana sails down the length of the Amazon.[41]
1542–43 – Juan Rodriguez Cabrillo explores the coasts of modern Baja and California from Punta Baja to the Russian River, discovering the Channel Islands; after his death, his second-in-command, Bartolomé Ferrer, reaches Point Arena.[42]
1542 or 1543 – Fernão Mendes Pinto, António Mota and Francisco Zeimoto reach Tanegashima, Japan.[1]
1543 – Ruy López de Villalobos discovers three islands (Fais, Ulithi and Yap) in the Carolines and eight atolls (Kwajalein, Lae, Ujae, Wotho, Likiep, Wotje, Erikub and Maloelap) in the Marshall Islands.[35]
1543 – Jean Alfonce explores up the Saguenay River, believing it to be "la mer du Cattay".[7]
1553 – Hugh Willoughby seeks a Northeast Passage over Russia; reaches either Kolguyev Island or Novaya Zemlya.[43]
1556 – Steven Borough reaches as far as Kara Strait, between Novaya Zemlya and Vaygach Island.[43]
1557–59 – Juan Fernández Ladrillero and Cortés Hojea explore the Chilean coast from Valdivia (39° 48’ S) to Canal Santa Barbara (54° S); the former passes through the western entrance of the Strait of Magellan to its eastern entrance and back.[2]
1565 – Miguel López de Legazpi discovers Mejit, Ailuk and Jemo in the Marshall Islands, while his subordinate Alonso de Arellano discovers Lib in the same island group, as well as five islands (Oroluk, Chuuk, Pulap, Sorol and Ngulu) in the Caroline Islands.[35]
1568 – Álvaro de Mendaña discovers the Solomon Islands.[3]
1576 – Martin Frobisher discovers "Meta Incognita" ("the unknown bourne"; Baffin Island) and what he believes to be a passage to Cathay: "Frobishers Streytes" (Frobisher Bay).[7]
1577–80 – Sir Francis Drake completes the second circumnavigation of the globe.[44]
1578 – Frobisher sails part way up the "Mistaken Straites" (Hudson Strait).[7]
1581–82 – Yermak Timofeyevich and his men cross the Ural Mountains and reach as far as Isker on the banks of the Irtysh (near modern Tobolsk).[45][46]
1585 – John Davis explores Davis Strait, reaching 66°40′ N; also sails up Cumberland Sound, thinking it to be a "passage to Cathay".[7]
1587 – Davis sails up the west coast of Greenland as far as 72°46′ N (about modern Upernavik).[7]
1589 – João da Gama reaches "Yezo" (Hokkaido).[47]
1592 – Davis discovers the Falkland Islands.[48]
1595 – Mendaña discovers the Marquesas.[3]
1596 – Willem Barentsz discovers Spitsbergen.[49]

text: 17th century[edit]

text:
1600–01 – Prince Miron Shakhovskoi and D. Khripunov descend the Ob to the Ob Estuary and ascend the Taz River, establishing the ostrog of Mangazeya about 161 kilometres (100 mi) to 240 kilometres (150 mi) from its mouth.[46][50]
1602–06 – Bento de Góis travels overland from India to China, via Afghanistan and the Pamirs.[51]
1605 – Ketsk serving men ascend the Ket, portage to the Yenisei, and descend it to its confluence with the Sym.[52]
1606 – Willem Janszoon discovers Australia at the mouth of the Pennefather River on the western coast of the Cape York Peninsula, exploring its coast from Badu Island south to Cape Keerweer (13°58′ S).[53]
1606 – Pedro Fernandes de Queirós discovers Espiritu Santo, the largest island in what is now the nation of Vanuatu.[53]
1606 – Luís Vaz de Torres sails through the strait that now bears his name.[53]
1607 – Mangazeyan promyshlenniki and traders reach the lower Yenisei, establish Turukhansk, and ascend the Lower Tunguska, while Ketsk serving men ascend the Yenisei to the Angara, which they also ascend.[52]
1607 – Henry Hudson coasts the east coast of Greenland, naming "Hold-with-Hope" (around 73° N).[54]
1609 – Hudson sails the Halve Maen up the Hudson River as fall north as present day Albany, New York.[55]
1610 – Étienne Brûlé ascends the Ottawa River and reaches Lake Nipissing and Georgian Bay in Lake Huron.[56]
1610 – Kondratiy Kurochkin leads an expedition, sailing in kochi, from Turukhansk to the mouth of the Yenisei and east to the mouth of the Pyasina on the Taymyr Peninsula.[43][46]
1610 – A detachment from Mangazeya ascends the Yenisei a further 640 kilometres (400 mi) to its confluence with the Sym.[52]
1610–11 – Hudson sails through Hudson Strait into Hudson Bay, where he overwinters in James Bay.[57]
1611 – Mangazeyan men reach the Khatanga.[58]
1612–13 – Thomas Button is the first to explore the western shores of Hudson Bay, where he winters in the mouth of the Nelson River; also discovers Coats and Southampton Islands.[59]
1614 – Whalers discover Jan Mayen.[60]
1615–16 – Étienne Brûlé sights the western shore of Lake Ontario, descends the Niagara River, explores what are now parts of modern New York and Pennsylvania, and descends the Susquehanna River to Chesapeake Bay.[56]
1616 – Jacob Le Maire and Willem Schouten discover and name Le Maire Strait, Staten Island, and Cape Horn; also discover Tonga (Niuafo'ou, Niuatoputapu, and Tafahi), Futuna and Alofi (in modern Wallis and Futuna), and several islands in the Tuamotu (Takaroa, Takapoto, Manihi, Ahe and Rangiroa) and Bismarck Archipelagos (including New Hanover and New Ireland).[2][35]
1616 – Robert Bylot and William Baffin reach 77°30′ N, enter Baffin Bay, discover Smith, Jones, and Lancaster Sounds and sight the coasts of Ellesmere, Devon, and Bylot Islands.[61]
1616 – Dirk Hartog explores some 576 kilometres (358 mi) of coastline (the coast of Western Australia from about 22° to 28° S), discovering Dirk Hartog Island and Shark Bay.[62]
1617 – English walrus hunters sight the southern coast of "Sir Thomas Smith's Island" (Nordaustlandet).[49]
1618 – Pedro Páez is believed to be the first European to see and describe the source of the Blue Nile in Ethiopia.[63]
1618 – Lenaert Jacobszoon discovers an "island" at 22° S (the coast of Western Australia from Point Cloates to North West Cape).[53]
1619 – Frederick de Houtman sights the coast of Western Australia near Fremantle and sails along the coast north for over 640 kilometres (400 mi).[53]
1620 – Mangazeyan serving men reach the Vilyuy River and descend it to its confluence with the Lena.[52]
1621–23 – Étienne Brûlé and his companion Grenolle travel along the North Channel of Lake Huron (probably sighting Manitoulin Island) to "Grand Lac" (Lake Superior) via St. Mary's River.[56]
1622 – The Dutch ship Leeuwin discovers land near present-day Cape Leeuwin.[62]
1623 – Jan Carstenszoon discovers the western coast of Cape York Peninsula from Cape Keerweer to the southern mouth of the Gilbert River; while his consort Willem Joosten van Colster discovers "Arnhemsland" and "Speultsland" (modern Arnhem Land and perhaps Groote Eylandt).[62][64]
1624 – António de Andrade crosses the Himalayas through the Mana Pass and reaches Tibet.[51]
1627 – Jesuit missionaries Estêvão Cacella and João Cabral cross the Himalayas and are the first to enter Bhutan.[51][65]
1627 – François Thijssen, accompanied by Pieter Nuyts, discovers over 1,609 kilometres (1,000 mi) of coastline east of Cape Leeuwin to the eastern end of the Great Australian Bight.[53]
1628 – Cabral is the first to enter Nepal.[51]
1628 – Gerrit Frederikszoon de Witt captain of the Vianen discovers "Witsland" about 21° S, sailing 320 kilometres (200 mi) along the coast and discovering Barrow Island and parts of the Dampier Archipelago.[62]
1628–30 – Vasilii Bugor ascends the Upper Tunguska and portages to the upper Lena, descending it to its confluence with the Kirenga.[46][52]
1631–32 – Luke Foxe and Thomas James, in separate expeditions, both circumnavigate Hudson Bay in search of a Northwest Passage; Foxe sails through the channel and into the basin now named after him to 66°47′ N, while James winters in the bay named after him.[59]
1632–33 – Pyotr Beketov descends the Lena as far as its great bend, erects the ostrog Yakutsk, and sends a detachment some 720 kilometres (450 mi) downriver (where the zimovie Zhigansk is built) and another east up the Aldan as far as the Amga (which they also ascend in search of yasak).[46][50]
1633–34 – Jean Nicolet discovers Lake Michigan and likely reaches Green Bay, Wisconsin.[66]
1633–38 – Ilya Perfilyev and Ivan Rebrov sail from Zhigansk in kochi some 800 kilometres (500 mi) downriver to the mouth of the Lena and sail along the coast east and west, reaching the mouths of the Olenyok, Yana, and Indigirka rivers.[46][67]
1638–40 – Poznik Ivanov crosses the Verkhoyansk Range into the upper reaches of the Yana, and then portages over the Chersky Range into the Indigirka River system.[46][67]
1639–40 – Maksim Perfilyev ascends the Vitim River to the Tsipa, which he also ascends (until rapids force him to turn back), becoming the first Russian to enter Transbaikal.[46]
1639–41 – Ivan Moskvitin ascends the Maya, portages across the Dzhugdzhur Mountains, and descends the Ulya to the Sea of Okhotsk; two groups are sent to the north and south, reaching the mouths of the Taui and Uda rivers, respectively.[45][46]
1641 – Dmitri Zyrian discovers the Alazeya, which he ascends as far as the tree line.[46]
1642–43 – Abel Tasman discovers "Anthony van Diemenslandt" (Tasmania) and "Staten Landt" (New Zealand); following year discovers "'t Eylandt Amsterdam" (Tongatapu), Fiji and New Britain.[35][62]
1643 – Kurbat Ivanov reaches the western shores of Lake Baikal, opposite Olkhon.[68]
1643 – Maarten Gerritsz Vries sails along the eastern coast of "Yezo" (Hokkaidō), between Iturup and Urup, to Sakhalin.[3]
1643 – Vasiliy Sychev discovers the Anabar, where he establishes the zimovie Anabarskoye.[58][69]
1643–45 – Vassili Poyarkov crosses the Stanovoy Range and descends the Zeya to the Amur, which he follows to its mouth; from here, he coasts along the Sea of Okhotsk to the Ulya (on the way sighting the Shantar Islands).[70]
1644 – Tasman maps the northern coast of Australia, connecting "Nova Guinea" (the Cape York Peninsula) with "the land of D'Eendracht" (Western Australia).[62]
1644 – Mikhail Stadukhin reaches the Kolyma.[46]
1644–47 – Ivan Pokhabov is the first to ascend the Angara to Lake Baikal, which he crosses to the Selenga; he later ascends it and reaches Urga (in present-day Mongolia).[46][50]
1646 – Isaya Ignatyev reaches Chaunskaya Bay.[43]
1648–49 – Semyon Dezhnyov sails from the Kolyma, rounds Cape Dezhnev (thus proving Asia and America are separate), and reaches the Anadyr River, which he ascends for some 563 kilometres (350 mi) (here he builds the zimovie Anadyrsk).[45]
1649–51 – Yerofey Khabarov ascends the Olyokma River, crosses the northern Yablonoi Mountains, and descends the Amur to its confluence with the Songhua.[45][70]
1650 – Stadukhin and Semen Motora travel from the Kolyma, across the Anyuyskiy Range, to Anadyrsk.[45]
1651–57 – Stadukhin travels from Anadyrsk to the mouth of the Penzhina River, then west along the northern coast of the Sea of Okhotsk to Okhotsk.[46][67]
1653–54 – Beketov ascends the Khilok, crosses the southern Yablonoi Mountains, and descends the Ingoda and Shilka rivers to the latter's confluence with the Nercha (where his men build the ostrog Nerchinsk).[46]
1654 – Médard Chouart des Groseilliers explores the entire western shore of Lake Michigan.[71]
1659 – Groseilliers and Pierre-Esprit Radisson explore the southern shore of Lake Superior as far west as Chequamegon Bay.[71]
1661 – Johann Grueber and Albert Dorville are the first to visit Lhasa.[72]
1669 – Robert de la Salle discovers the Ohio, descending it as far as the Falls of Ohio at the site of modern Louisville, Kentucky.[73]
1673 – Louis Jolliet and Jacques Marquette reach the upper Mississippi, descending it to its confluence with the Arkansas; also discover the Missouri.[73]
1675 – Anthony de la Roché discovers South Georgia.[citation needed]
1682 – Robert de La Salle descends the "Rivière de Colbert" (Mississippi) to its mouth.[73]
1688–89 – Jacques de Noyon discovers Rainy Lake and Lake of the Woods.[71]
1690–92 – Henry Kelsey travels from York Factory southwestward, probably reaching the Saskatchewan and the headwaters of the Assiniboine—in the process becoming the first European to see the Canadian Prairies.[71]
1696 – Luka Morozko travels almost halfway down the west coast of Kamchatka, reaching the Tigil River.[67]
1697–99 – Vladimir Atlasov reaches as far as the Golygina River on the southwest coast of Kamchatka, from which he sights Atlasov Island; also crosses the Sredinny Range (twice), reaching Olyutorsky Gulf and the Kamchatka River.[46][67]

text: 18th century[edit]

text:
1706 – Mikhail Nasedkin reaches Cape Lopatka and sights Shumshu, northernmost of the Kuril Islands.[67]
1710 – Yakov Permyakov discovers Bolshoy Lyakhovsky Island.[citation needed]
1713 – Ivan Kozyrevsky reaches Shumshu and Paramushir.[67]
1714 – Étienne de Veniard, Sieur de Bourgmont ascends the Missouri as far as the Platte, becoming the first to enter the present-day Nebraska.[29]
1720 – Pedro de Villasur travels from Santa Fe, through what is now part of southeastern Colorado, to the lower Platte in eastern Nebraska.[29]
1722 – Jakob Roggeveen discovers "Paasch Eiland" (Easter Island) and Tutuila and Upolu.[74][75]
1728 – Vitus Bering sails through the strait that now bears his name; also discovers and names Saint Lawrence Island.[43]
1732 – Mikhail Gvozdev discovers the "Large Country" (Alaska).[70]
1734 – Jean Baptiste de La Vérendrye discovers Lake Winnipeg.[71]
1734–37 – Stepan Muravev and Mikhail Pavlov chart the Russian coast from Arkhangelsk to just east of the Pechora, while Stepan Malygin charts it from there to the Ob River, including the Yamal Peninsula.[45]
1735–36 – Vasili Pronchishchev charts the Russian coast from the Lena west to the Khatanga.[45]
1737 – Dmitry Ovtsyn charts the Russian coast from the mouth of the Ob to the Yenisei.[45]
1738 – Pierre de La Vérendrye visits Mandan villages near the site of present-day Bismarck, North Dakota.[76]
1738–40 – Fyodor Minin charts the Russian coast from the Yenisei to the Pyasina.[45]
1739 – Jean Bouvet de Lozier discovers "Cape Circumcision" (Bouvet Island).[77]
1739–41 – Dmitry Laptev charts the Russian coast from the Lena to just east of the Kolyma.[45]
1741 – Bering sights Mount St. Elias, the entrance of Prince William Sound, the Alaska Peninsula (from Cape Providence to Chignik Bay) and several of the Aleutian Islands (discovering Great Sitkin, Atka, and Kiska), as well as discovering Kayak, Montague, Hinchinbrook, Sitkalidak, and the Shumagin and Commander Islands; his second-in-command, Aleksei Chirikov, sights Mounts Fairweather and Douglas and discovers Noyes and Baker Islands (both off the west coast of Prince of Wales Island), as well as Baranof, Chichagof, Kruzof, Yakobi, Kodiak, Afognak, the Aleutian Islands (Umnak, Adak, Agattu, Attu, and the Islands of Four Mountains), and the Kenai Peninsula.[78]
1741–42 – Khariton Laptev and Semion Chelyuskin chart the Taymyr Peninsula, with the latter reaching Cape Chelyuskin, the northernmost point of Asia.[45]
1742 – Christopher Middleton discovers Wager Bay and Repulse Bay.[79]
1742–43 – Louis-Joseph Gaultier de La Vérendrye and his brother François reach the Big Horn Mountains of modern Wyoming; on their return they reach the vicinity of present-day Pierre, South Dakota.[76][80]
1747 – Jeremiah Westall discovers Chesterfield Inlet and sails about sixty miles up it.[79]
1761–62 – William Christopher sails 370 kilometres (230 mi) into Chesterfield Inlet to the western end of Baker Lake.[79]
1767 – Samuel Wallis discovers "King George's Land" (Tahiti).[81]
1769 – José Ortega discovers San Francisco Bay.[39]
1769–70 – James Cook circumnavigates both islands of New Zealand, proving they aren't part of Terra Australis Incognita; also discovers the east coast of Australia from Cape Howe to Cape York.[81]
1771–72 – Samuel Hearne reaches the Coppermine, descending it to what would become known as Coronation Gulf; the following year, on his way back, he becomes the first to sight and cross Great Slave Lake.[29]
1772 – Yves-Joseph de Kerguelen-Trémarec discovers the Kerguelen Islands.[77]
1772 – Pedro Fages sights the Sierra Nevada.[82]
1773 – Ivan Lyakhov reaches Kotelny Island.[43]
1773–75 – Cook is the first to cross the Antarctic Circle, reaching 71° 10’ S, thus finally disproving the existence of Terra Australis Incognita; also discovers New Caledonia and the South Sandwich Islands.[81]
1774 – Juan José Pérez Hernández explores the western coast of North America from Cape Mendocino northwards, discovering the Queen Charlotte Islands, Vancouver Island, and Dall Island.[83]
1775 – Bruno de Heceta discovers the mouth of the Columbia River; his consort Juan Francisco de la Bodega y Quadra discovers Prince of Wales Island (Bucareli Bay).[84]
1776 – Francisco Atanasio Domínguez and Silvestre Vélez de Escalante follow the Rio Grande north to the modern state of Colorado, where they travel west, discovering Utah Lake.[29]
1777–78 – Cook discovers Christmas Island and Hawaii; also explores the Alaskan coast as far north as Icy Cape, discovering Cook Inlet and Prince William Sound.[81]
1787 – Charles William Barkley discovers the Strait of Juan de Fuca.[79]
1788 – Captain Arthur Phillip arrives with The First Fleet in Botany Bay on the coast of Sydney, Australia.
1789 – Alexander Mackenzie descends the Mackenzie River to its mouth in the Arctic Ocean.[85]
1791 – Francisco de Eliza discovers the "Canal de Nuestra Señora del Rosario" (Strait of Georgia); José María Narváez explores up it, passing the mouth of the Fraser River and reaching as far north as Texada Island.[84]
1791–94 – George Vancouver, together with William Broughton, Peter Puget, Joseph Whidbey, and James Johnstone, charts the modern states of Oregon and Washington, the coast of British Columbia, and the Alaska Panhandle, discovering Admiralty, Mitkof and Wrangell Islands in the Alexander Archipelago, as well as proving the insularity of Kuiu and Revillagigedo Islands; also charts Admiralty Inlet and Puget Sound and discovers the Chatham Islands and The Snares.[86]
1792 – Dionisio Alcalá Galiano and Cayetano Valdés y Flores circumnavigate Vancouver Island, proving its insularity.[29]
1792 – Jacinto Caamaño enters Clarence Strait, showing that much of the Alaska Panhandle is an archipelago, not mainland, as had been presumed; also sights the southwest coast of Revillagigedo Island.[29]
1792–93 – Mackenzie ascends the Peace and Parsnip, crosses the Canadian Rockies to the headwaters of the Fraser, ascends the West Road River and crosses the Coast Mountains, reaching the Bella Coola, which he descends to North Bentinck Arm and Dean Channel.[85]
1796 – Mungo Park reaches the upper Niger, exploring it from Ségou to Silla.[87]
1797–98 – George Bass explores from Cape Howe to Western Port, discovering Bass Strait.[62]
1798 – John Fearn discovers "Pleasant Island" (Nauru).[35]
1798 – Francisco de Lacerda travels from Tete northwest to Lake Mweru.[88]
1798–99 – Matthew Flinders and George Bass circumnavigate Tasmania, proving its insularity.[62]

text: 19th century[edit]

text:
1800 – James Grant discovers the Australian coastline from Cape Banks to Cape Otway.[62]
c. 1801–04 – A fur trading post is built on Great Bear Lake.[89]
1802 – John Murray discovers Port Phillip Bay.[62]
1802 – Matthew Flinders explores the coast from Fowlers Bay to Encounter Bay, discovering Spencer Gulf, Kangaroo Island, and Gulf St. Vincent.[62]
1802 – Nicolas Baudin explores the coast from Cape Banks to Encounter Bay, where he meets Flinders.[62]
1802–03 – Flinders circumnavigates Australia.[62]
1805–06 – Meriwether Lewis and William Clark, from Fort Mandan, ascend the Missouri to its headwaters, cross the Continental Divide via Lemhi Pass in the Bitterroot Range to enter the present state of Idaho, and descend the Clearwater and Snake rivers to the Columbia, which they descend to its mouth; on the way back Lewis explores the Blackfoot and Sun rivers, as well as the headwaters of the Marias, while Clark travels through Bozeman Pass and descends the Yellowstone to its confluence with the Missouri.[90]
1805–06 – Mungo Park descends the Niger as far as the Bussa rapids, where he is drowned.[87]
1806 – Yakov Sannikov discovers New Siberia Island.[77]
1806 – Abraham Bristow discovers the Auckland Islands.[91]
1808 – Simon Fraser descends the Fraser River for some 800 kilometres (500 mi) to its mouth, reaching the Strait of Georgia.[29]
1810 – Frederick Hasselborough discovers Campbell and Macquarie Islands.[77]
1811–12 – Wilson Price Hunt discovers Union Pass in the Wind River Range and reaches the upper Snake River, while Robert Stuart discovers South Pass—his route would later become the Oregon Trail.[29]
1816 – Otto von Kotzebue discovers Kotzebue Sound.[29]
1819 – William Smith discovers the South Shetland Islands.[92]
1819–20 – William Edward Parry enters Lancaster Sound and reaches Melville Island, discovering and naming Cornwallis, Bathurst, and Somerset Islands; the following year sights "Banks Land" (Banks Island).[93]
1820 – Edward Bransfield sights the Antarctic Peninsula; also discovers northernmost islands of the South Shetlands.[77]
1820–21 – Fabian Gottlieb von Bellingshausen discovers the northernmost islands of the South Sandwich group; following year discovers Peter I and Alexander Islands.[94]
1821 – John Franklin explores over 800 kilometres (500 mi) of coastline from the mouth of the Coppermine River to Point Turnagain on the Kent Peninsula.[95]
1821 – Sealers Nathaniel Palmer and George Powell discover "Powell's Islands" (South Orkney Islands).[96]
1821–23 – Parry explores the eastern side of the Melville Peninsula, reaching the western entrance of Fury and Hecla Strait; also explores the northern coast of Foxe Basin.[97]
1823 – Dixon Denham, Walter Oudney, and Hugh Clapperton are the first Europeans to sight Lake Chad.[98]
1823 – Sealer James Weddell sails to 74°15′ S into "King George IV's Sea" (Weddell Sea).[99]
1824 – Samuel Black ascends the Finlay to Thutade Lake, source of the Finlay-Peace-Slave-Mackenzie river system; then portages to the Stikine and Turnagain.[100]
1824–25 – Étienne Provost, Jim Bridger, and Peter Skene Ogden independently reach Great Salt Lake.[29]
1825–26 – Franklin explores the Arctic coastline from the mouth of the Mackenzie River west to Point Beechey, while his partner John Richardson explores east to the Coppermine River, naming Dolphin and Union Strait and discovering "Wollaston Land" (part of the southern coast of Victoria Island) — combining to chart over 1,930 kilometres (1,200 mi) of coastline; Richardson also surveys the five arms of Great Bear Lake.[101]
1826 – Frederick William Beechey charts the Alaskan coastline from Icy Cape to Point Barrow; also discovers Vanavana, Fangataufa, and Ahunui in the Tuamotu archipelago.[102]
1826 – Alexander Gordon Laing becomes the first European to reach the fabled city of Timbuktu.[98]
1827 – Jedediah Smith crosses the Sierra Nevada (via Ebbetts Pass) and Great Basin.[29]
1828 – René Caillié is the first European to return alive from Timbuktu.
1829–30 – John Ross discovers "Boothia Felix" (the Boothia Peninsula); the following year his nephew James Clark Ross crosses its narrow isthmus and reaches King William Island.[103]
1830 – Richard Lander and his brother John descend the Niger for more than 643 kilometres (400 mi) from Bussa to its mouth.[5]
1831–32 – John Biscoe discovers Enderby Land; following year discovers Adelaide, Anvers, and Biscoe Islands.[77]
1833 – Andrei Glazunov and Semyon Lukin discover the mouth of the Yukon River.[29]
1833–35 – Pyotr Pakhtusov and Avgust Tsivolko chart the entire east coast of Yuzhny Island, as well as the east coast of Severny Island north to nearly 74°24’ N.[77]
1834 – George Back descends the Back River to Chantrey Inlet.[104]
1837 – Glazunov ascends the Unalakleet and portages to the middle Yukon.[105]
1837–39 – Peter Warren Dease and Thomas Simpson reach Point Barrow from the east; following two summers they map the region from Point Turnagain to just north of the Castor and Pollux River on the Boothia Peninsula and chart the coastline of "Victoria Land" (Victoria Island) from Point Back to Point Parry.[106]
1838 – Pyotr Malakhov reaches Nulato, near the confluence of the Koyukuk and Yukon.[105]
1838–40 – Jules Dumont d'Urville discovers the Joinville Island group and Adélie Land (138°21′ E).[77]
1839 – John Balleny discovers the Balleny Islands and sights the Sabrina Coast (121° E).[91]
1840 – Charles Wilkes discovers Wilkes Land, mapping 2,414 kilometres (1,500 mi) of the Antarctic coast from Piner Bay (140° E) to the Shackleton Ice Shelf (97° E), proving that Antarctica is a continent.[107]
1841–43 – James Clark Ross discovers the Ross Sea, reaches 78°09′30″ S, and discovers the active volcano Mount Erebus on Ross Island, the Ross Ice Shelf, and Victoria Land; also sights Snow Hill, Seymour, and James Ross Islands.[108]
1845 – John Bell discovers the Porcupine, which he descends to its confluence with the Yukon.[105]
1846 – Candido José da Costa Cardoso discovers Lake Malawi.[88]
1846 – Rodrigues Graça travels from Angola to southwestern Katanga.[88]
1846–47 – John Rae maps over 1,046 kilometres (650 mi) of coastline, from Lord Mayor Bay to Cape Crozier, discovering Committee Bay.[109]
c. 1847–48 – António da Silva Porto reaches the upper Zambezi.[88]
1848 – Johannes Rebmann is the first to sight Mount Kilimanjaro.[110]
1849 – David Livingstone and William Cotton Oswell cross the Kalahari Desert to Lake Ngami.[88]
1849 – James Clark Ross charts 240 kilometres (150 mi) of the west coast of Somerset Island south to Cape Coulman, discovering Peel Sound.[111]
1850 – Edwin De Haven sails up Wellington Channel, discovering and naming "Grinnell Land" (the Grinnell Peninsula, which forms the northwestern corner of Devon Island).[111]
1850–54 – Robert McClure transits the Northwest Passage (by boat and sledge); he and his men also chart some 2,736 kilometres (1,700 mi) of new coastline, consisting of the entire coast of Banks Island and much of the northwestern coast of Victoria Island (from just east of Point Reynolds in the north to Prince Albert Sound in the south), in the process discovering Prince of Wales Strait and McClure Strait.[112][113]
1851 – Rae charts over 965 kilometres (600 mi) of the southern coastline of Victoria Island, from Cape Back to Pelly Point.[109]
1851 – Erasmus Ommanney, Sherard Osborn and William Browne chart the northern half of Prince of Wales Island, Osborn west to Sherard Osborn Point (72°20’ N) and Browne east to Pandora Island; meanwhile, Robert D. Aldrich charts the west coast of the Bathurst Island group north to Cape Aldrich (about 76°11’ N, on Île Vanier) and Dr. Abraham Bradford charts the east coast of Melville Island north to Bradford Point.[77][114]
1851 – Robert Campbell descends the Pelly to the Yukon, which he descends to its confluence with the Porcupine, reaching Fort Yukon.[105]
1851–52 – William Kennedy and Joseph René Bellot discover Bellot Strait and cross Prince of Wales Island east to west, reaching Ommanney Bay.[111]
1852 – Edward Augustus Inglefield reaches 78° 28’ N, entering Smith Sound; also charts Jones Sound as far west as 84° 10’ W.[115]
1852–53 – Edward Belcher sails two of his squadron to the northwestern coast of the Grinnell Peninsula, wintering at 77° 52’ N, 97° W; later circumnavigates the peninsula via Arthur Strait (now Fiord), discovering Cornwall and North Kent.[111]
1853 – Richard Vesey Hamilton and George Henry Richards chart the Sabine Peninsula of Melville Island from Cape Mudge east to Bradford Point; the latter, along with Sherard Osborn, also charts the northern coast of Bathurst Island.[111][116]
1853 – George Mecham discovers Prince Patrick and Eglinton Islands and charts the southwest corner of Melville Island; along with Francis Leopold McClintock, he charts nearly the entire coast of Prince Patrick; McClintock also charts the northwest coast of Melville Island, from Cape Fisher northwest to Cape Scott and south along its west coast to Cape Purchase.[116][117]
1853–54 – Elisha Kent Kane and his men chart the Kane Basin and discover Kennedy Channel; one of his men, William Morton, reaches as far north as Kap Constitution (81° 22’ N).[118]
1853–56 – Livingstone becomes the first to traverse Africa from west to east, traveling from Luanda in Angola to Quelimane in Mozambique; also explores much of the upper Zambezi and discovers and names Victoria Falls.[88]
1854 – Rae charts the Boothia Peninsula from the Castor and Pollux River north to Point de la Guiche, discovering Rae Strait and proving the insularity of King William Island.[109]
1858 – Richard Francis Burton and John Hanning Speke discover Lake Tanganyika and Lake Victoria.[119]
1859 – McClintock charts the remaining 193 kilometres (120 mi) of the continental coastline of America (on the west coast of the Boothia Peninsula), while his companion Allen Young charts the southern half of Prince of Wales Island.[111]
1860–61 – Robert O'Hara Burke and William Wills are the first to cross Australia from south to north, traveling from Melbourne to the Flinders River.[5]
1862 – Speke discovers the Nile flowing from the northern end of Lake Victoria.[5]
1862 – Ivan Lukin ascends the Yukon to Fort Yukon.[105]
1864 – Samuel Baker discovers "Luta Nzige" (Lake Albert); in the distance he sights the Mountains of the Moon (the Rwenzori).[5]
1865 – Edward Whymper is the first to ascend the Matterhorn.[5]
1869–70 – Carl Koldewey and Julius von Payer explore the east coast of Greenland from 74°18’ to 77°01’N.[120]
1871 – Charles Francis Hall reaches Robeson Channel, sailing his ship as far north as 82° 11’ N; he later travels by sledge to 83° 05’ N.[121]
1872 – William Adams proves the insularity of Bylot Island.[77]
1873–74 – Karl Weyprecht and Von Payer discover and name Franz Josef Land.[120]
1875–76 – George Nares sails as far north as 82° 24’ N; following year Albert Hastings Markham sledges to 83° 20’ 26" N, while Pelham Aldrich sledges along the northern coast of Ellesmere Island east to Alert Point and Lewis A. Beaumont explores the northwestern coast of Greenland.[121]
1875–77 – Henry Morton Stanley circumnavigates both Lakes Tanganyika and Victoria, sights Lake George, and descends the Lualaba and Congo to the sea.[122]
1876 – Luigi D'Albertis ascends over 800 kilometres (500 mi) up the Fly River in New Guinea.[123]
1878–79 – Adolf Erik Nordenskiöld is the first to transit the Northeast Passage.[124]
1881–83 – Adolphus Greely explores the interior of Ellesmere Island, discovering Lake Hazen; one of his men, James Booth Lockwood, crosses the island and reaches Greely Fiord, as well as sledging eastwards to the vicinity of Kap Washington (reaching 83° 23’08" N in the process).[121]
1883–84 – Franz Boas is the first to see Nettilling Lake.[77]
1887–89 – Stanley traverses the Ituri Rainforest, explores the Rwenzori, and follows the Semliki to its source (which he names Lake Edward).[122]
1892 – Robert Peary discovers and names Independence Bay and Peary Land.[120]
1893–96 – Fridtjof Nansen and Hjalmar Johansen sledge to 86°13'06" N; their ship, the Fram, under Otto Sverdrup, drifts in the ice from the New Siberian Islands west to the northwest coast of Spitsbergen, reaching 85°55'05" N—a new record for a ship.[120]
1898–1902 – Sverdrup and Gunnar Isachsen chart the western coast of Ellesmere Island and discover and name Axel Heiberg, Ellef Ringnes, Amund Ringnes, and King Christian Islands.[125]

text: 20th century[edit]

text:
1900 – Peary explores the north coast of Greenland from Kap Washington to Kap Clarence Wyckoff, on the way reaching Cape Morris Jesup, the most northern point of mainland Greenland.[126]
1902–04 – Robert Falcon Scott traces the length of the Ross Ice Shelf, discovers the Edward VII Peninsula, reaches about 82°11’ S (in the process tracing 600 kilometres (370 mi) of the west coast of the shelf), crosses the Transantarctic Mountains and discovers the Antarctic Plateau, penetrating nearly 240 kilometres (150 mi) into it; he is also the first to see the dry valleys of the Antarctic.[127]
1903–06 – Roald Amundsen transits the Northwest Passage in the sloop Gjøa; Godfred Hansen, his second-in-command, charts the east coast of Victoria Island north to Cape Nansen (72°02' N, 104°45' W).[128]
1906–07 – Ludvig Mylius-Erichsen and Johan Peter Koch chart the northeast coast of Greenland from Kap Bismarck (76°42' N) to Kap Clarence Wyckoff (82°52' N), discovering Danmark Fjord.[77]
1908–09 – Frederick Cook and Peary each claim to have reached the North Pole—the former is a fraud, the latter widely doubted.[120]
1910–11 – Bernhard Hantzsch crosses Baffin Island from Cumberland Sound to the Koukdjuak River, exploring the west coast of the island north to 68°45’N.[77]
1911–12 – Amundsen is the first to reach the South Pole; Scott and his team reach the Pole over a month later, all perishing on the return journey.[127]
1913–14 – Boris Vilkitsky and Per Novopashennyy discover Severnaya Zemlya, surveying parts of its eastern coast from Mys Arkticheskiy to Mys Vaygacha (its southeast point), as well as much of its south coast west to Mys Neupokoyeva.[129]
1915–17 – Vilhjalmur Stefansson discovers Brock, Mackenzie King, Borden, Meighen, and Lougheed Islands; one of his men, Storker T. Storkerson, charts part of the northeast coast of Victoria Island, discovering the Storkerson Peninsula and Stefansson Island.[77][130]
1924–29 – Joseph Dewey Soper explores the interior of Baffin Island before surveying its west coast north to Hantzsch River.[77]
1926 – Amundsen, Lincoln Ellsworth and Umberto Nobile in the airship Norge are the first definitely known to have sighted the North Pole.[120]
1927 – George P. Putnam charts the north coast of the Foxe Peninsula from Cape Dorchester to Bowman Bay.[77]
1930–32 – Georgy Ushakov and Nikolay Urvantsev survey the entire coast of Severnaya Zemlya, showing it to be made up of four main islands: October Revolution, Komsomolets, Pioneer, and Bolshevik Islands—in all surveying some 2,200 kilometres (1,400 mi) of coastline and interior.[129]
1932 – W. A. Poole discovers Prince Charles Island.[131]
1934 – Richard E. Byrd discovers and names Roosevelt Island.
1937–41 – Thomas and Ella Manning map the west coast of Baffin Island from the Hantzsch River to Steensby Inlet.[77]
1940 – Byrd discovers Thurston Island, believing it to be a peninsula.
1948 – E. C. Kerslake charts Prince Charles, Air Force, and Foley Islands.[29]
1950 – Maurice Herzog and Louis Lachenal are the first to ascend Annapurna.[132]
1953 – Edmund Hillary and Tenzing Norgay are the first to ascend Mount Everest.[133]
1954 – Lino Lacedelli and Achille Compagnoni are the first to ascend K2.[134]
1957 – Finn Ronne discovers Berkner Island.


document_title: Sing (2016 American film)

question_text: who does the voice for meena in sing

question_tokens: who does the voice for meena in sing

root

text: Sing (2016 American film)

text: Plot[edit]

text: In a world of anthropomorphic animals, koala Buster Moon owns a theater, having been interested in show business since his father took him to his first music show as a child. Following financial problems brought up by the bank representative Judith, he tells his wealthy friend Eddie that he will host a singing competition with a prize of $1,000. But Buster's assistant, Miss Crawly, accidentally appends two extra zeroes, and the promotional fliers showing $100,000 are blown out of Buster's office into the city streets.

tag: p

text: Animals from all around the city gather for auditions. Those selected include: housewife and mother of 25 piglets Rosita; street musician mouse Mike; mobster's son gorilla Johnny; and punk-rock porcupine Ash. Shy teenage elephant Meena fails her audition out of stage fright, while Ash's boyfriend Lance is dismissed from the contest. Rosita is paired with another contestant, an exuberant pig named Gunter, for a dance routine. Although Buster discovers the flyers show a prize of $100,000 (money he does not have), he remains optimistic. Buster convinces Eddie to arrange a visit with Eddie's grandmother, former opera singer and theater actress Nana Noodleman, to persuade her to sponsor the prize money. She is hesitant to contribute, but agrees to see a private screening of the show.

text: Encouraged by her grandfather, Meena tries to ask Buster for another chance, but becomes his stage hand instead. When one of the acts quits, and another is injured, Meena is added as an act. The performers' individual problems begin to hinder rehearsals: Rosita flounders in her dance routine with Gunter, after having been distracted by her parenting duties that have fallen into disarray. After discovering Lance broke up with her for not being around anymore, with a new girlfriend named Becky and evicting them from her apartment, Ash is devastated and breaks down while singing her assigned song, Carly Rae Jepsen's "Call Me Maybe." Johnny is torn between having to help his father as the driver of a getaway car in a heist and making the practices. When he tries to do both, he does not show up for the planned pickup in time, and his father and his gang are arrested. Meena does not get any help in overcoming her stage fright, and Mike, certain that the prize money is as good as his, buys a fancy car to impress a female mouse, and then swindles a group of bears in a card game at a nightclub.

text: The day of the screening, the bears interrupt the show, demanding the money from Mike, who in turn, points to Buster. The bears open the chest containing the prize money, but it is nowhere near $100,000. The glass tank full of luminescent squids that Buster got to light up the theater breaks under all their weight, flooding the theater, which then comes crashing down. With the lot repossessed by Judith, Buster, who had been living in his theater's office desk, takes up residence at Eddie's place (his parents' pool house). Although the contestants (besides Mike, who saw Buster as a fraud) visit him and try to cheer him up, Buster is too despondent to listen to them. He tries to start over by opening a car wash, using the same bucket that his father had used to earn money for Buster's theater.

text:
When Meena goes to the theater's rubble lot and sings Leonard Cohen's "Hallelujah", Buster hears her and is inspired to reinstate the show without the prize money. They perform on a makeshift stage on the lot in front of Rosita and Meena's family members. As Rosita and Gunter perform Taylor Swift's "Shake It Off", which finally gets her husband Norman's attention to her, more animals are attracted to the scene as the show is broadcast on the news. Johnny's rendition of Elton John's "I'm Still Standing" impresses his father, who then escapes from prison to reconcile with him. Despite an interruption by Judith, Ash sings her original rock song "Set It All Free." Mike returns to the show and sings Frank Sinatra's "My Way." Meena finally overcomes her fears and sings Stevie Wonder's "Don't You Worry 'bout a Thing", which literally brings down the house.
The show becomes a success and impresses Nana, who was in the audience. Nana buys the lot and the theater is rebuilt and reopened.

text: Voice cast[edit]

text:
Matthew McConaughey as Buster Moon, an optimistic koala who plans to save his theater from closure by holding a singing competition.[3][5]
Reese Witherspoon as Rosita, a pig who gave up her teenage music dreams to become a devoted wife to Norman, and mother to their 25 piglets.[5]
Seth MacFarlane as Mike, a white mouse with a big Frank Sinatra-esque voice and an arrogant attitude.[5]
Scarlett Johansson as Ash, a teenage porcupine punk rocker who takes part in an alternative-rock music duo with her boyfriend Lance.[1][5]
John C. Reilly as Eddie Noodleman, a sheep and Buster's friend who doubts the future of the theater.[5][6]
Taron Egerton as Johnny, a teenage gorilla who wants to sing, though his father would rather have him follow his criminal footsteps.[5]
Tori Kelly as Meena, a teenage elephant with an exquisite voice and severe stage fright.[5]
Jennifer Saunders as Nana Noodleman, a sheep and Eddie's grandmother who was a singer in her glory days.[7][8]
Jennifer Hudson[1] as Young Nana
Garth Jennings as Miss Crawly, an elderly iguana with a glass eye who is Buster's administrative assistant.[1]
Peter Serafinowicz as Big Daddy, a gorilla gang leader who wants his son Johnny to follow in his crime business.[1]
Nick Kroll as Gunter, a passionate dancing pig who is partnered with Rosita for the show.[9][7]
Beck Bennett as Lance, a porcupine and Ash's boyfriend.[1]
Jay Pharoah[7] as Meena's grandfather who pressures her to overcome her stage fright.
Nick Offerman[7] as Norman, a pig and Rosita's husband.
Leslie Jones as Meena's mother
Rhea Perlman as Judith,[1][10] a brown llama from the bank who warns Buster that his theater will be repossessed if he does not pay.
Laraine Newman as Meena's grandmother
Adam Buxton as Stan, a gorilla who is a member of Big Daddy's gang.
Brad Morris as Baboon, whom Mike attacks for not donating more money to his street performances.
Bill Farmer as News Reporter Dog, who documents Buster's singing competition.

tag: ul

text: The voices of Rosita's piglet children were provided by Oscar, Leo, Caspar, and Asa Jennings, the children of Garth Jennings, the film's writer and director.  Jennings had directors Edgar Wright and Wes Anderson provide  "additional voices", continuing a tradition of the three friends appearing in each other's films.[11]

text: Production[edit]

text: In January 2014, it was announced that Garth Jennings would write and direct an animated comedy film for Universal Pictures and Illumination Entertainment, about "courage, competition and carrying a tune,"[12] which was originally titled Lunch,[13] and then retitled as Sing.[5]

text: On January 14, 2015, Matthew McConaughey was cast in the film's lead voice role.[3] Chris Meledandri and Janet Healy produced the film.[3] On June 17, 2015, it was confirmed that McConaughey's character is named Buster and that John C. Reilly would voice Eddie, a sheep and Buster's best friend.[6] In November 2015, it was announced that Reese Witherspoon, Seth MacFarlane, Scarlett Johansson, Tori Kelly and Taron Egerton had joined the cast of the film.[5]

text: The film features 65 pop songs, the rights to which cost 15 percent of the film's $75 million budget.[14] The animation was created entirely in France by Illumination MacGuff.[15]

text: Soundtrack[edit]

text: A soundtrack album for the film was released on December 21, 2016.

text: Release[edit]

text: The almost complete[16] film was screened as a work in progress beginning September 11, 2016 at the Toronto International Film Festival.[17] Universal Studios released the film on December 21, 2016.[18]

text: Home media[edit]

text: Sing was released on Blu-ray, Blu-ray 3D, Ultra HD Blu-ray and DVD on March 21, 2017. It includes three short films: Gunter Babysits, Love at First Sight, and Eddie's Life Coach.[19]

text:
In Gunter Babysits, Gunter offers to watch over Rosita and Norman's piglets while they are away as he works to prove himself to be a good babysitter.
In Love at First Sight, Johnny sets Miss Crawly up with an online dating website where she manages to score a date with a lizard named Herman.
In Eddie's Life Coach, Eddie's mother sets Eddie up for a digital training seminar where he will be assigned to a dachshund named Garry "The Winner" Wishman.

text: Reception[edit]

text: Box office[edit]

text: Sing grossed $270.3 million in the United States and Canada, and $363.8 million in other territories, for a worldwide total of $634.1 million, against a production budget of $75 million.[2] Deadline Hollywood calculated the net profit of the film to be $194.2 million, when factoring together all expenses and revenue for the film, making it the 7th most profitable release of 2016.[20]

text: In North America, the film opened alongside Passengers and Assassin's Creed, and was expected to gross around $70 million from 4,022 theaters over its first six days of release.[21] The film made $1.7 million during its Tuesday night previews.[22] It went on to gross $35.2 million in its opening weekend (a six-day total of $75.5 million), finishing second at the box office behind Rogue One: A Star Wars Story, which was in its second week.[23] It rose 21% in its second weekend to $42.9 million, remaining in second, and grossed $20.8 million in its third week and finishing third.[24] Sing holds the record for being the highest-grossing film to never finish first at the North American box office, besting My Big Fat Greek Wedding ($241.4 million in 2002).[25]

text: Critical response[edit]

text: On the aggregate site Rotten Tomatoes, the film has an approval rating of 73% based on 168 reviews, and an average rating of 6.5/10. The site's critical consensus reads, "Sing delivers colorfully animated, cheerfully undemanding entertainment with a solid voice cast and a warm-hearted – albeit familiar – storyline that lives up to its title."[26] On Metacritic, the film has a weighted average score of 59 out of 100 based on 37 critics, indicating "mixed or average reviews."[27] Audiences polled by CinemaScore gave the film an average grade of "A" on an A+ to F scale.[28]

text: Brian Truitt of USA Today gave the film three-and-a-half out of four stars and wrote, "In a year full of talking-animal hits, Sing isn't quite as strong a number. It's a tale that might not be particularly thought-provoking but sure is toe-tapping."[29] In her review for the Los Angeles Times, Katie Walsh called Sing, "a cute movie with genuinely funny moments (keep an eye out for the koala car wash), and some great tunes to boot."[30] The Arizona Republic's Bill Goodykoontz was rather mixed about the movie in his review and overall said, "Sing is like an album with a good song here and there, but too much filler and not enough hits."[31] Reviewing the version of the film screened at the Toronto International Film Festival, Stefan Pape of the British website HeyUGuys gave the film a mixed review of 2/5, stating that "Garth Jennings's Sing effectively acknowledges early on that it's following a completely unoriginal formula, and yet carries on regardless."[32] While Peter Debruge of Variety, who also saw the film during the same festival, did not find the subplots to have any "profound life lessons," he overall praised Jennings' direction, the cast's voice performances and the film's silliness.[33]

text: Accolades[edit]

text:
List of awards and nominations

Award

Date of ceremony

Category

Recipient(s)

Result

Ref(s)

AARP Annual Movies for Grownups Awards

February 6, 2017

Best Movie for Grownups who Refuse to Grow Up

Sing

Nominated

[34]

Annie Awards

February 4, 2017

Outstanding Achievement, Music in an Animated Feature Production

Joby Talbot

[35]

Golden Globe Awards

January 8, 2017

Best Animated Feature Film

Sing

[36]

Best Original Song

"Faith" – Ryan Tedder, Stevie Wonder and Francis Farewell Starlite

Hollywood Music in Media Awards

November 17, 2016

Best Song – Animated Film

[37][38]

Best Soundtrack Album

Sing: Original Motion Picture Soundtrack

Outstanding Music Supervision – Film

Jojo Villanueva

Won

Nickelodeon Kids' Choice Awards

March 11, 2017

Favorite Animated Movie

Sing

Nominated

[39]

Favorite Voice From an Animated Movie

Reese Witherspoon

Most Wanted Pet

Favorite Soundtrack

Sing

Saturn Awards

June 28, 2017

Best Animated Film

Nominated

[40]

tag: table

text: Sequel[edit]

text: Universal and Illumination have announced plans for a sequel, tentatively titled Sing 2, slated for December 25, 2020. [41]


document_title: Yuga

question_text: according to hindu mythology how many yugas are there

text: Yuga

text: Four yugas[edit]

text: There are four Yugas in one cycle:

text:
Satya Yuga
Treta Yuga
Dwapara Yuga
Kali Yuga

text: Characteristics of each Yuga[edit]

text:
Satya Yuga (also known as Krita Yuga "Golden Age"): The first and best Yuga. It was the age of truth and perfection. The Krita Yuga was so named because there was but one religion, and all men were saintly: therefore they were not required to perform religious ceremonies. Humans were gigantic, powerfully built, honest, youthful, vigorous, erudite and virtuous. The Vedas were one. All mankind could attain to supreme blessedness. There was no agriculture or mining as the earth yielded those riches on its own. Weather was pleasant and everyone was happy. There were no religious sects. There was no disease, decrepitude or fear of anything.[citation needed]
Treta Yuga: Is considered to be the second Yuga in order, however Treta means the "Third". In this age, virtue diminishes slightly. At the beginning of the age, many emperors rise to dominance and conquer the world. Wars become frequent and weather begins to change to extremities. Oceans and deserts are formed.  People become slightly diminished compared to their predecessors. Agriculture, labour and mining become existent.[citation needed]
Dvapara Yuga: Is considered to be the third Yuga in order.  Dvapara means "two pair" or "after two". In this age, people become tainted with Tamasic qualities and aren't as strong as their ancestors. Diseases become rampant. Humans are discontent and fight each other. Vedas are divided into four parts. People still possess characteristics of youth in old age. Average lifespan of humans is around a few centuries.
Kali Yuga: The final age. It is the age of darkness and ignorance. People become sinners and lack virtue. They become slaves to their passions and are barely as powerful as their earliest ancestors in the Satya Yuga. Society falls into disuse and people become liars and hypocrites. Knowledge is lost and scriptures are diminished. Humans eat forbidden and dirty food. The environment is polluted, water and food become scarce. Wealth is heavily diminished.  Families become non-existent. By the end of Kali Yuga the average lifespan of humans will be as low as 70 years.[citation needed]

text: Durations of the four Yugas[edit]

text: According to one Puranic astronomical estimate, the four Yuga have the following durations:[3]

text:
Satya Yuga equals 1,728,000 Human years[4]
Treta Yuga equals 1,296,000 Human years[4]
Dvapara Yuga equals 864,000 Human years[4]
Kali Yuga equals 432,000 Human years[4]

text: Together, these four yuga constitute one Mahayuga and equal 4.32 million human years.[3] According to one version, there are 1,000 Mahayugas in one day of Brahma or 4.32 billion human years. A Mahakalpa consists of 100 years of Brahma.[3]

text: According to Srimad Bhagavatam 3.11.19, which is dated around the 400–500 BC,[5] the Yugas are much longer, using a divine year in which one day is equal to one human year, thus:

text: one year of the demigods is equal to 360 years of the human beings. The duration of the Satya-yuga is therefore 4,800 x 360, or 1,728,000 years. The duration of the Tretā-yuga is 3,600 x 360, or 1,296,000 years. The duration of the Dvāpara-yuga is 2,400 x 360, or 864,000 years.[6]

text: The Viṣṇu Purāṇa Time measurement section of the Viṣṇu Purāṇa Book I Chapter III adds:

text:
2 Ayanas (6-month periods, see above) = 1 human year or 1 day of the devas.
12,000 divine years = 4 Yugas (= 4,320,000 human years) = 1 Mahā-Yuga (also is equal to 12,000 Daiva (divine) Yuga).
2*12,000 = 24,000 divine year = 12000 revolutions of sun around its dual.

text: While the long yuga count is the most popular, it does not correlate to any known celestial motion found in the Astronomical Almanac. The value of 24,000 years fits relatively close with the modern astronomical calculation of one full precession of the equinox, which takes 25,772 years.[a] Thus the yuga cycle may have some basis in known terrestrial cycles. Srimad Bhagavatam 3.11.19 describes the timespans of the demigods, in which a year of a yuga is a year of the demigods. It is this second sloka which appears to have been modified over the years.

text: Decline[edit]

text: The ages see a gradual decline of dharma, wisdom, knowledge, intellectual capability, life span, emotional and physical strength.

text:
Satya Yuga –  Virtue reigns supreme. Human stature was 21 cubits. Average human lifespan was 100,000 years.
Treta Yuga – There was 3 quarter virtue and 1 quarter sin. Normal human stature was 14 cubits. Average human lifespan was 10,000 years.
Dwapara Yuga – There was 1 half virtue & 1 half sin. Normal human stature was 7 cubits. Average human lifespan was 1,000 years.
Kali Yuga – There is 1 quarter virtue & 3 quarter sin. Normal human stature is 3.5 cubits. Average human lifespan will be 100 years.

text: In the present days we may be said to live in a Kali Yuga, which is said to have started in 3102 BCE[7] with the end of the Mahabharata war. This date is also considered by many Hindus to be the day that Krishna left Earth and went to his abode.[b]


document_title: Optical telescope

question_text: the ability of a telescope to see details is called

question_tokens: the ability of a telescope to see details is called

text: Optical telescope

text: History[edit]

text: The telescope is more a discovery of optical craftsmen than an invention of a scientist.[1][2] The lens and the properties of refracting and reflecting light had been known since antiquity and theory on how they worked were developed by ancient Greek philosophers, preserved and expanded on in the medieval Islamic world, and had reached a significantly advanced state by the time of the telescope's invention in early modern Europe.[3][4] But the most significant step cited in the invention of the telescope was the development of lens manufacture for spectacles,[2][5][6] first in Venice and Florence in the thirteenth century,[7] and later in the spectacle making centers in both the Netherlands and Germany.[8] It is in the Netherlands in 1608 where the first recorded optical telescopes (refracting telescopes) appeared. The invention is credited to the spectacle makers Hans Lippershey and Zacharias Janssen in Middelburg, and the instrument-maker and optician Jacob Metius of Alkmaar.[9]

text: Galileo greatly improved[citation needed] on these designs the following year, and is generally credited as the first to use a telescope for astronomy. Galileo's telescope used Hans Lippershey's design of a convex objective lens and a concave eye lens, and this design is now called a Galilean telescope. Johannes Kepler proposed an improvement on the design[10] that used a convex eyepiece, often called the Keplerian Telescope.

text: The next big step in the development of refractors was the advent of the Achromatic lens in the early 18th century,[11] which corrected the chromatic aberration in Keplerian telescopes up to that time—allowing for much shorter instruments with much larger objectives.

text: For reflecting telescopes, which use a curved mirror in place of the objective lens, theory preceded practice. The theoretical basis for curved mirrors behaving similar to lenses was probably established by Alhazen, whose theories had been widely disseminated in Latin translations of his work.[12] Soon after the invention of the refracting telescope Galileo, Giovanni Francesco Sagredo, and others, spurred on by their knowledge that curved mirrors had similar properties as lenses, discussed the idea of building a telescope using a mirror as the image forming objective.[13] The potential advantages of using parabolic mirrors (primarily a reduction of spherical aberration with elimination of chromatic aberration) led to several proposed designs for reflecting telescopes,[14] the most notable of which was published in 1663 by James Gregory and came to be called the Gregorian telescope,[15][16] but no working models were built. Isaac Newton has been generally credited with constructing the first practical reflecting telescopes, the Newtonian telescope, in 1668[17] although due to their difficulty of construction and the poor performance of the speculum metal mirrors used it took over 100 years for reflectors to become popular. Many of the advances in reflecting telescopes included the perfection of parabolic mirror fabrication in the 18th century,[18] silver coated glass mirrors in the 19th century, long-lasting aluminum coatings in the 20th century,[19] segmented mirrors to allow larger diameters, and active optics to compensate for gravitational deformation. A mid-20th century innovation was catadioptric telescopes such as the Schmidt camera, which uses both a lens (corrector plate) and mirror as primary optical elements, mainly used for wide field imaging without spherical aberration.

text: The late 20th century has seen the development of adaptive optics and space telescopes to overcome the problems of astronomical seeing.

text: Principles[edit]

text: The basic scheme is that the primary light-gathering element the objective (1) (the convex lens or concave mirror used to gather the incoming light), focuses that light from the distant object (4) to a focal plane where it forms a real image (5). This image may be recorded or viewed through an eyepiece (2), which acts like a magnifying glass. The eye (3) then sees an inverted magnified virtual image (6) of the object.

text: Inverted images[edit]

text: Most telescope designs produce an inverted image at the focal plane; these are referred to as inverting telescopes. In fact, the image is both turned upside down and reversed left to right, so that altogether it is rotated by 180 degrees from the object orientation. In astronomical telescopes the rotated view is normally not corrected, since it does not affect how the telescope is used. However, a mirror diagonal is often used to place the eyepiece in a more convenient viewing location, and in that case the image is erect, but still reversed left to right. In terrestrial telescopes such as spotting scopes, monoculars and binoculars, prisms (e.g., Porro prisms) or a relay lens between objective and eyepiece are used to correct the image orientation. There are telescope designs that do not present an inverted image such as the Galilean refractor and the Gregorian reflector. These are referred to as erecting telescopes.

text: Design variants[edit]

text: Many types of telescope fold or divert the optical path with secondary or tertiary mirrors. These may be integral part of the optical design (Newtonian telescope, Cassegrain reflector or similar types), or may simply be used to place the eyepiece or detector at a more convenient position. Telescope designs may also use specially designed additional lenses or mirrors to improve image quality over a larger field of view.

text: Characteristics[edit]

text: Design specifications relate to the characteristics of the telescope and how it performs optically. Several properties of the specifications may change with the equipment or accessories used with the telescope; such as Barlow lenses, star diagonals and eyepieces. These interchangeable accessories don't alter the specifications of the telescope, however they alter the way the telescopes properties function, typically magnification, angular resolution and FOV.

text: Surface resolvability[edit]

text:
The smallest resolvable surface area of an object, as seen through an optical telescope, is the limited physical area that can be resolved. It is analogous to angular resolution, but differs in definition: instead of separation ability between point-light sources it refers to the physical area that can be resolved. A familiar way to express the characteristic is the resolvable ability of features such as Moon craters or Sun spots. Expression using the formula is given by the sum of twice the resolving power

R

{\displaystyle R}

 over aperture diameter

D

{\displaystyle D}

 multiplied by the objects diameter

D

o
b

{\displaystyle D_{ob}}

 multiplied by the constant

Φ

{\displaystyle \Phi }

 all divided by the objects apparent diameter

D

a

{\displaystyle D_{a}}

.[20][21]

text:
Resolving power

R

{\displaystyle R}

 is derived from the wavelength

λ

{\displaystyle {\lambda }}

 using the same unit as aperture; where 550 nm to mm is given by:

R
=

λ

10

6

=

550

10

6

=
0.00055

{\displaystyle R={\frac {\lambda }{10^{6}}}={\frac {550}{10^{6}}}=0.00055}

.
The constant

Φ

{\displaystyle \Phi }

 is derived from radians to the same unit as the objects apparent diameter; where the Moons apparent diameter of

D

a

=

313
Π

10800

{\displaystyle D_{a}={\frac {313\Pi }{10800}}}

 radians to arcsecs is given by:

D

a

=

313
Π

10800

∗
206265
=
1878

{\displaystyle D_{a}={\frac {313\Pi }{10800}}*206265=1878}

.

text:
An example using a telescope with an aperture of 130 mm observing the Moon in a 550 nm wavelength, is given by:

F
=

2
R

D

∗

D

o
b

∗
Φ

D

a

=

2
∗
0.00055

130

∗
3474.2
∗
206265

1878

≈
3.22

{\displaystyle F={\frac {{\frac {2R}{D}}*D_{ob}*\Phi }{D_{a}}}={\frac {{\frac {2*0.00055}{130}}*3474.2*206265}{1878}}\approx 3.22}

text: The unit used in the object diameter results in the smallest resolvable features at that unit. In the above example they are approximated in kilometers resulting in the smallest resolvable Moon craters being 3.22 km in diameter. The Hubble Space Telescope has a primary mirror aperture of 2400 mm that provides a surface resolvability of Moon craters being 174.9 meters in diameter, or sunspots of 7365.2 km in diameter.

text: Angular resolution[edit]

text: Ignoring blurring of the image by turbulence in the atmosphere (atmospheric seeing) and optical imperfections of the telescope, the angular resolution of an optical telescope is determined by the diameter of the primary mirror or lens gathering the light (also termed its "aperture").

text:
The Rayleigh criterion for the resolution limit

α

R

{\displaystyle \alpha _{R}}

 (in radians) is given by

text:
where

λ

{\displaystyle \lambda }

 is the wavelength and

D

{\displaystyle D}

 is the aperture. For visible light (

λ

{\displaystyle \lambda }

 = 550 nm) in the small-angle approximation, this equation can be rewritten:

text:
Here,

α

R

{\displaystyle \alpha _{R}}

 denotes the resolution limit in arcseconds and

D

{\displaystyle D}

 is in millimeters. In the ideal case, the two components of a double star system can be discerned even if separated by slightly less than

α

R

{\displaystyle \alpha _{R}}

. This is taken into account by the Dawes limit

text: The equation shows that, all else being equal, the larger the aperture, the better the angular resolution. The resolution is not given by the maximum magnification (or "power") of a telescope. Telescopes marketed by giving high values of the maximum power often deliver poor images.

text: For large ground-based telescopes, the resolution is limited by atmospheric seeing. This limit can be overcome by placing the telescopes above the atmosphere, e.g., on the summits of high mountains, on balloon and high-flying airplanes, or in space. Resolution limits can also be overcome by adaptive optics, speckle imaging or lucky imaging for ground-based telescopes.

text: Recently, it has become practical to perform aperture synthesis with arrays of optical telescopes. Very high resolution images can be obtained with groups of widely spaced smaller telescopes, linked together by carefully controlled optical paths, but these interferometers can only be used for imaging bright objects such as stars or measuring the bright cores of active galaxies.

text: Focal length and focal ratio[edit]

text:
The focal length of an optical system is a measure of how strongly the system converges or diverges light. For an optical system in air, it is the distance over which initially collimated rays are brought to a focus. A system with a shorter focal length has greater optical power than one with a long focal length; that is, it bends the rays more strongly, bringing them to a focus in a shorter distance. In astronomy, the f-number is commonly referred to as the focal ratio notated as

N

{\displaystyle N}

. The focal ratio of a telescope is defined as the focal length

f

{\displaystyle f}

 of an objective divided by its diameter

D

{\displaystyle D}

 or by the diameter of an aperture stop in the system. The focal length controls the field of view of the instrument and the scale of the image that is presented at the focal plane to an eyepiece, film plate, or CCD.

text:
An example of a telescope with a focal length of 1200 mm and aperture diameter of 254 mm is given by:

N
=

f
D

=

1200
254

≈
4.7

{\displaystyle N={\frac {f}{D}}={\frac {1200}{254}}\approx 4.7}

text: Numerically large Focal ratios are said to be long or slow. Small numbers are short or fast. There are no sharp lines for determining when to use these terms, an individual may consider their own standards of determination. Among contemporary astronomical telescopes, any telescope with a focal ratio slower (bigger number) than f/12 is generally considered slow, and any telescope with a focal ratio faster (smaller number) than f/6, is considered fast. Faster systems often have more optical aberrations away from the center of the field of view and are generally more demanding of eyepiece designs than slower ones. A fast system is often desired for practical purposes in astrophotography with the purpose of gathering more photons in a given time period than a slower system, allowing time lapsed photography to process the result faster.

text: Wide-field telescopes (such as astrographs), are used to track satellites and asteroids, for cosmic-ray research, and for astronomical surveys of the sky. It is more difficult to reduce optical aberrations in telescopes with low f-ratio than in telescopes with larger f-ratio.

text: Light-gathering power[edit]

text:
The light-gathering power of an optical telescope, also referred to as light grasp or aperture gain, is the ability of a telescope to collect a lot more light than the human eye. Its light-gathering power is probably its most important feature. The telescope acts as a light bucket, collecting all of the photons that come down on it from a far away object, where a larger bucket catches more photons resulting in more received light in a given time period, effectively brightening the image. This is why the pupils of your eyes enlarge at night so that more light reaches the retinas. The gathering power

P

{\displaystyle P}

 compared against a human eye is the squared result of the division of the aperture

D

{\displaystyle D}

 over the observer's pupil diameter

D

p

{\displaystyle D_{p}}

,[20][21] with an average adult having a pupil diameter of 7mm. Younger persons host larger diameters, typically said to be 9mm, as the diameter of the pupil decreases with age.

text:
An example gathering power of an aperture with 254 mm compared to an adult pupil diameter being 7 mm is given by:

P
=

(

D

D

p

)

2

=

(

254
7

)

2

≈
1316.7

{\displaystyle P=\left({\frac {D}{D_{p}}}\right)^{2}=\left({\frac {254}{7}}\right)^{2}\approx 1316.7}

text:
Light-gathering power can be compared between telescopes by comparing the areas

A

{\displaystyle A}

 of the two different apertures.

text:
As an example, the light-gathering power of a 10 meter telescope is 25x that of a 2 meter telescope:

p
=

A

1

A

2

=

π

5

2

π

1

2

=
25

{\displaystyle p={\frac {A_{1}}{A_{2}}}={\frac {\pi 5^{2}}{\pi 1^{2}}}=25}

text: For a survey of a given area, the field of view is just as important as raw light gathering power. Survey telescopes such as the Large Synoptic Survey Telescope try to maximize the product of mirror area and field of view (or etendue) rather than raw light gathering ability alone.

text: Magnification[edit]

text: The magnification through a telescope magnifies a viewing object while limiting the FOV. Magnification is often misleading as the optical power of the telescope, its characteristic is the most misunderstood term used to describe the observable world. At higher magnifications the image quality significantly reduces, usage of a Barlow lens—which increases the effective focal length of an optical system—multiplies image quality reduction.

text: Similar minor effects may be present when using star diagonals, as light travels through a multitude of lenses that increase or decrease effective focal length. The quality of the image generally depends on the quality of the optics (lenses) and viewing conditions—not on magnification.

text: Magnification itself is limited by optical characteristics. With any telescope or microscope, beyond a practical maximum magnification, the image looks bigger but shows no more detail. It occurs when the finest detail the instrument can resolve is magnified to match the finest detail the eye can see. Magnification beyond this maximum is sometimes called empty magnification.

text: To get the most detail out of a telescope, it is critical to choose the right magnification for the object being observed. Some objects appear best at low power, some at high power, and many at a moderate magnification. There are two values for magnification, a minimum and maximum. A wider field of view eyepiece may be used to keep the same eyepiece focal length whilst providing the same magnification through the telescope. For a good quality telescope operating in good atmospheric conditions, the maximum usable magnification is limited by diffraction.

text: Visual[edit]

text:
The visual magnification

M

{\displaystyle M}

 of the field of view through a telescope can be determined by the telescopes focal length

f

{\displaystyle f}

 divided by the eyepiece focal length

f

e

{\displaystyle f_{e}}

 (or diameter).[20][21] The maximum is limited by the diameter of the eyepiece.

text:
An example of visual magnification using a telescope with a 1200 mm focal length and 3 mm eyepiece is given by:

M
=

f

f

e

=

1200
3

=
400

{\displaystyle M={\frac {f}{f_{e}}}={\frac {1200}{3}}=400}

text: Minimum[edit]

text:
There is a lowest usable magnification on a telescope. The increase in brightness with reduced magnification has a limit related to something called the exit pupil. The exit pupil is the cylinder of light coming out of the eyepiece, hence the lower the magnification, the larger the exit pupil. The minimum

M

m

{\displaystyle M_{m}}

 can be calculated by dividing the telescope aperture

D

{\displaystyle D}

 over the exit pupil diameter

D

e
p

{\displaystyle D_{ep}}

.[22] Decreasing the magnification past this limit cannot increase brightness, at this limit there is no benefit for decreased magnification. Likewise calculating the exit pupil

D

e
p

{\displaystyle D_{ep}}

 is a division of the aperture diameter

D

{\displaystyle D}

 and the visual magnification

M

{\displaystyle M}

 used. The minimum often may not be reachable with some telescopes, a telescope with a very long focal length may require a longer-focal-length eyepiece than is possible.

text:
An example of the lowest usable magnification using a 254 mm aperture and 7 mm exit pupil is given by:

M

m

=

D

D

e
p

=

254
7

≈
36

{\displaystyle M_{m}={\frac {D}{D_{ep}}}={\frac {254}{7}}\approx 36}

, whilst the exit pupil diameter using a 254 mm aperture and 36x magnification is given by:

D

e
p

=

D
M

=

254
36

≈
7

{\displaystyle D_{ep}={\frac {D}{M}}={\frac {254}{36}}\approx 7}

text: Optimum[edit]

text: A useful reference is:

text:
For small objects with low surface brightness (such as galaxies), use a moderate magnification.
For small objects with high surface brightness (such as planetary nebulae), use a high magnification.
For large objects regardless of surface brightness (such as diffuse nebulae), use low magnification, often in the range of minimum magnification.

text: Only personal experience determines the best optimum magnifications for objects, relying on observational skills and seeing conditions.

text: Field of view[edit]

text: Field of view is the extent of the observable world seen at any given moment, through an instrument (e.g., telescope or binoculars), or by naked eye. There are various expressions of field of view, being a specification of an eyepiece or a characteristic determined from and eyepiece and telescope combination. A physical limit derives from the combination where the FOV cannot be viewed larger than a defined maximum, due to diffraction of the optics.

text: Apparent[edit]

text: Apparent FOV is the observable world observed through an ocular eyepiece without insertion into a telescope. It is limited by the barrel size used in a telescope, generally with modern telescopes that being either 1.25 or 2 inches in diameter. A wider FOV may be used to achieve a more vast observable world given the same magnification compared with a smaller FOV without compromise to magnification. Note that increasing the FOV lowers surface brightness of an observed object, as the gathered light is spread over more area, in relative terms increasing the observing area proportionally lowers surface brightness dimming the observed object. Wide FOV eyepieces work best at low magnifications with large apertures, where the relative size of an object is viewed at higher comparative standards with minimal magnification giving an overall brighter image to begin with.

text: True[edit]

text:
True FOV is the observable world observed though an ocular eyepiece inserted into a telescope. Knowing the true FOV of eyepieces is very useful since it can be used to compare what is seen through the eyepiece to printed or computerized star charts that help identify what is observed. True FOV

v

t

{\displaystyle v_{t}}

 is the division of apparent FOV

v

a

{\displaystyle v_{a}}

 over magnification

M

{\displaystyle M}

.[20][21]

text:
An example of true FOV using an eyepiece with 52° apparent FOV used at 81.25x magnification is given by:

v

t

=

v

a

M

=

52
81.25

=

0.64

∘

{\displaystyle v_{t}={\frac {v_{a}}{M}}={\frac {52}{81.25}}=0.64^{\circ }}

text: Maximum[edit]

text:
Max FOV is a term used to describe the maximum useful true FOV limited by the optics of the telescope, it is a physical limitation where increases beyond the maximum remain at maximum. Max FOV

v

m

{\displaystyle v_{m}}

 is the barrel size

B

{\displaystyle B}

 over the telescopes focal length

f

{\displaystyle f}

 converted from radian to degrees.[20][21]

text:
An example of max FOV using a telescope with a barrel size of 31.75 mm (1.25 inches) and focal length of 1200 mm is given by:

v

m

=
B
∗

180
π

f

≈
31.75
∗

57.2958
1200

≈

1.52

∘

{\displaystyle v_{m}=B*{\frac {\frac {180}{\pi }}{f}}\approx 31.75*{\frac {57.2958}{1200}}\approx 1.52^{\circ }}

text: Observing through a telescope[edit]

text: There are many properties of optical telescopes and the complexity of observation using one can be a daunting task; experience and experimentation are the major contributors to understanding how to maximize one's observations. In practice, only two main properties of a telescope determine how observation differs: the focal length and aperture. These relate as to how the optical system views an object or range and how much light is gathered through an ocular eyepiece. Eyepieces further determine how the field of view and magnification of the observable world change.

text: Observable world[edit]

text: Observable world describes what can be seen using a telescope, when viewing an object or range the observer may use many different techniques. Understanding what can be viewed and how to view it depends on the field of view. Viewing an object at a size that fits entirely in the field of view is measured using the two telescope properties—focal length and aperture, with the inclusion of an ocular eyepiece with suitable focal length (or diameter). Comparing the observable world and the angular diameter of an object shows how much of the object we see. However, the relationship with the optical system may not result in high surface brightness. Celestial objects are often dim because of their vast distance, and detail may be limited by diffraction or unsuitable optical properties.

text: Field of view and magnification relationship[edit]

text:
Finding what can be seen through the optical system begins with the eyepiece providing the field of view and magnification; the magnification is given by the division of the telescope and eyepiece focal lengths. Using an example of an amateur telescope such as a Newtonian telescope with an aperture

D

{\displaystyle D}

 of 130 mm (5") and focal length

f

{\displaystyle f}

 of 650 mm (25.5 inches), one uses an eyepiece with a focal length

d

{\displaystyle d}

 of 8 mm and apparent field of view

v

a

{\displaystyle v_{a}}

 of 52°. The magnification at which the observable world is viewed is given by:

M
=

f
d

=

650
8

=
81.25

{\displaystyle M={\frac {f}{d}}={\frac {650}{8}}=81.25}

. The true field of view

v

t

{\displaystyle v_{t}}

 requires the magnification, which is formulated by its division over the apparent field of view:

v

t

=

v

a

M

=

52
81.25

=
0.64

{\displaystyle v_{t}={\frac {v_{a}}{M}}={\frac {52}{81.25}}=0.64}

. The resulting true field of view is 0.64°, allowing an object such as the Orion nebula, which appears elliptical with an angular diameter of 65 × 60 arcminutes, to be viewable through the telescope in its entirety, where the whole of the nebula is within the observable world. Using methods such as this can greatly increase one's viewing potential ensuring the observable world can contain the entire object, or whether to increase or decrease magnification viewing the object in a different aspect.

text: Brightness factor[edit]

text: The surface brightness at such a magnification significantly reduces, resulting in a far dimmer appearance. A dimmer appearance results in less visual detail of the object. Details such as matter, rings, spiral arms, and gases may be completely hidden from the observer, giving a far less complete view of the object or range. Physics dictates that at the theoretical minimum magnification of the telescope, the surface brightness is at 100%. Practically, however, various factors prevent 100% brightness; these include telescope limitations (focal length, eyepiece focal length, etc.) and the age of the observer.

text:
Age plays a role in brightness, as a contributing factor is the observer's pupil. With age the pupil naturally shrinks in diameter; generally accepted a young adult may have a 7 mm diameter pupil, an older adult as little as 5 mm, and a younger person larger at 9 mm. The minimum magnification

m

{\displaystyle m}

 can be expressed as the division of the aperture

D

{\displaystyle D}

 and pupil

p

{\displaystyle p}

 diameter given by:

m
=

D
d

=

130
7

≈
18.6

{\displaystyle m={\frac {D}{d}}={\frac {130}{7}}\approx 18.6}

. A problematic instance may be apparent, achieving a theoretical surface brightness of 100%, as the required effective focal length of the optical system may require an eyepiece with too large a diameter.

text:
Some telescopes cannot achieve the theoretical surface brightness of 100%, while some telescopes can achieve it using a very small-diameter eyepiece. To find what eyepiece is required to get minimum magnification one can rearrange the magnification formula, where it is now the division of the telescope's focal length over the minimum magnification:

F
m

=

650
18.6

≈
35

{\displaystyle {\frac {F}{m}}={\frac {650}{18.6}}\approx 35}

. An eyepiece of 35 mm is a non-standard size and would not be purchasable; in this scenario to achieve 100% one would require a standard manufactured eyepiece size of 40 mm. As the eyepiece has a larger focal length than the minimum magnification, an abundance of wasted light is not received through the eyes.

text: Exit pupil[edit]

text:
The increase in surface brightness as one reduces magnification is limited; that limitation is what is described as the exit pupil: a cylinder of light that projects out the eyepiece to the observer. An exit pupil must match or be smaller in diameter than one's pupil to receive the full amount of projected light; a larger exit pupil results in the wasted light. The exit pupil

e

{\displaystyle e}

 can be derived with from division of the telescope aperture

D

{\displaystyle D}

 and the minimum magnification

m

{\displaystyle m}

, derived by:

e
=

D
m

=

130
18.6

≈
7

{\displaystyle e={\frac {D}{m}}={\frac {130}{18.6}}\approx 7}

. The pupil and exit pupil are almost identical in diameter, giving no wasted observable light with the optical system. A 7 mm pupil falls slightly short of 100% brightness, where the surface brightness

B

{\displaystyle B}

 can be measured from the product of the constant 2, by the square of the pupil

p

{\displaystyle p}

 resulting in:

B
=
2
∗

p

2

=
2
∗

7

2

=
98

{\displaystyle B=2*p^{2}=2*7^{2}=98}

. The limitation here is the pupil diameter; it's an unfortunate result and degrades with age. Some observable light loss is expected and decreasing the magnification cannot increase surface brightness once the system has reached its minimum usable magnification, hence why the term is referred to as usable.

text: Image Scale[edit]

text: When using a CCD to record observations, the CCD is placed in the focal plane. Image scale (sometimes called plate scale) describes how the angular size of the object being observed is related to the physical size of the projected image in the focal plane

text:
i
=

α
s

,

{\displaystyle i={\frac {\alpha }{s}},}

text:
where

i

{\displaystyle i}

 is the image scale,

α

{\displaystyle \alpha }

 is the angular size of the observed object, and

s

{\displaystyle s}

 is the physical size of the projected image. In terms of focal length image scale is

text:
i
=

1
f

,

{\displaystyle i={\frac {1}{f}},}

text:
where

i

{\displaystyle i}

 is measured in radians per meter (rad/m), and

f

{\displaystyle f}

 is measured in meters. Normally

i

{\displaystyle i}

 is given in units of arcseconds per millimeter ("/mm). So if the focal length is measured in millimeters, the image scale is

text:
i

(
″

/

m
m
)
=

1

f
(
m
m
)

[

180
×
3600

π

]

.

{\displaystyle i(''/mm)={\frac {1}{f(mm)}}\left[{\frac {180\times 3600}{\pi }}\right].}

text:
The derivation of this equation is fairly straightforward and the result is the same for reflecting or refracting telescopes. However, conceptually it is easier to derive by considering a reflecting telescope. If an extended object with angular size

α

{\displaystyle \alpha }

 is observed through a telescope, then due to the Laws of reflection and Trigonometry the size of the image projected onto the focal plane will be

text:
s
=
tan

(
α
)
f
.

{\displaystyle s=\tan(\alpha )f.}

text: Thefore, the image scale (angular size of object divided by size of projected image) will be

text:
i
=

α
s

=

α

tan

(
α
)
f

,

{\displaystyle i={\frac {\alpha }{s}}={\frac {\alpha }{\tan(\alpha )f}},}

text:
and by using the small angle relation

tan

(
a
)
≈
a

{\displaystyle \tan(a)\approx a}

, when

a
<<
1

{\displaystyle a<<1}

 (N.B. only valid if

a

{\displaystyle a}

 is in radians), we obtain

text:
i
=

α

α
f

=

1
f

.

{\displaystyle i={\frac {\alpha }{\alpha f}}={\frac {1}{f}}.}

text: Imperfect images[edit]

text: No telescope can form a perfect image. Even if a reflecting telescope could have a perfect mirror, or a refracting telescope could have a perfect lens, the effects of aperture diffraction are unavoidable. In reality, perfect mirrors and perfect lenses do not exist, so image aberrations in addition to aperture diffraction must be taken into account. Image aberrations can be broken down into two main classes, monochromatic, and polychromatic. In 1857, Philipp Ludwig von Seidel (1821–1896) decomposed the first order monochromatic aberrations into five constituent aberrations. They are now commonly referred to as the five Seidel Aberrations.

text: The five Seidel aberrations[edit]

text: Optical defects are always listed in the above order, since this expresses their interdependence as first order aberrations via moves of the exit/entrance pupils. The first Seidel aberration, Spherical Aberration, is independent of the position of the exit pupil (as it is the same for axial and extra-axial pencils). The second, coma, changes as a function of pupil distance and spherical aberration, hence the well-known result that it is impossible to correct the coma in a lens free of spherical aberration by simply moving the pupil. Similar dependencies affect the remaining aberrations in the list.

text: Chromatic aberrations[edit]

text: Astronomical research telescopes[edit]

text: Optical telescopes have been used in astronomical research since the time of their invention in the early 17th century. Many types have been constructed over the years depending on the optical technology, such as refracting and reflecting, the nature of the light or object being imaged, and even where they are placed, such as space telescopes. Some are classified by the task they perform such as Solar telescopes.

text: Large reflectors[edit]

text: Nearly all large research-grade astronomical telescopes are reflectors. Some reasons are:

text:
In a lens the entire volume of material has to be free of imperfection and inhomogeneities, whereas in a mirror, only one surface has to be perfectly polished.
Light of different colors travels through a medium other than vacuum at different speeds. This causes chromatic aberration.
Reflectors work in a wider spectrum of light since certain wavelengths are absorbed when passing through glass elements like those found in a refractor or catadioptric.
There are technical difficulties involved in manufacturing and manipulating large-diameter lenses. One of them is that all real materials sag in gravity. A lens can only be held by its perimeter. A mirror, on the other hand, can be supported by the whole side opposite to its reflecting face.

text: Most large research reflectors operate at different focal planes, depending on the type and size of the instrument being used. These including the prime focus of the main mirror, the cassegrain focus (light bounced back down behind the primary mirror), and even external to the telescope all together (such as the Nasmyth and coudé focus).[23]

text: A new era of telescope making was inaugurated by the Multiple Mirror Telescope (MMT), with a mirror composed of six segments synthesizing a mirror of 4.5 meters diameter. This has now been replaced by a single 6.5 m mirror. Its example was followed by the Keck telescopes with 10 m segmented mirrors.

text: The largest current ground-based telescopes have a primary mirror of between 6 and 11 meters in diameter. In this generation of telescopes, the mirror is usually very thin, and is kept in an optimal shape by an array of actuators (see active optics). This technology has driven new designs for future telescopes with diameters of 30, 50 and even 100 meters.

text: Relatively cheap, mass-produced ~2 meter telescopes have recently been developed and have made a significant impact on astronomy research. These allow many astronomical targets to be monitored continuously, and for large areas of sky to be surveyed. Many are robotic telescopes, computer controlled over the internet (see e.g. the Liverpool Telescope and the Faulkes Telescope North and South), allowing automated follow-up of astronomical events.

text: Initially the detector used in telescopes was the human eye. Later, the sensitized photographic plate took its place, and the spectrograph was introduced, allowing the gathering of spectral information. After the photographic plate, successive generations of electronic detectors, such as the charge-coupled device (CCDs), have been perfected, each with more sensitivity and resolution, and often with a wider wavelength coverage.

text: Current research telescopes have several instruments to choose from such as:

text:
imagers, of different spectral responses
spectrographs, useful in different regions of the spectrum
polarimeters, that detect light polarization.

text: The phenomenon of optical diffraction sets a limit to the resolution and image quality that a telescope can achieve, which is the effective area of the Airy disc, which limits how close two such discs can be placed. This absolute limit is called the diffraction limit (and may be approximated by the Rayleigh criterion, Dawes limit or Sparrow's resolution limit). This limit depends on the wavelength of the studied light (so that the limit for red light comes much earlier than the limit for blue light) and on the diameter of the telescope mirror. This means that a telescope with a certain mirror diameter can theoretically resolve up to a certain limit at a certain wavelength. For conventional telescopes on Earth, the diffraction limit is not relevant for telescopes bigger than about 10 cm. Instead, the seeing, or blur caused by the atmosphere, sets the resolution limit. But in space, or if adaptive optics are used, then reaching the diffraction limit is sometimes possible. At this point, if greater resolution is needed at that wavelength, a wider mirror has to be built or aperture synthesis performed using an array of nearby telescopes.

text: In recent years, a number of technologies to overcome the distortions caused by atmosphere on ground-based telescopes have been developed, with good results. See adaptive optics, speckle imaging and optical interferometry.