81. Murale Translate this page fatti di grandi dimensioni. Il quadrante della Specola è opera delcelebre costruttore inglese jesse ramsden. Il raggio è di 8 http://www.pd.astro.it/museo/Pagine/Strumenti/murale.htm

Quadrante Murale 1776 - Jesse Ramsden, Londra / In ottone / Raggio: 244 cm / Con rifrattore acromatico; lunghezza focale: 87 cm; apertura: 70 mm. Lo strumento prende il nome di quadrante per la forma a quarto di cerchio, mentre murale sta a significare che esso è fissato solidamente ad un muro. Serve a determinare l’altezza degli astri nell’istante del loro passaggio in meridiano. Prima dell’invenzione della macchina a dividere, le divisioni della fascia circolare chiamata lembo, venivano incise a mano. Per garantire la massima esattezza nell’incisione manuale delle graduazioni, e quindi evitare che errori nella suddivisione si ripercuotessero nelle misure di posizione, i quadranti murali venivano fatti di grandi dimensioni. Il quadrante della Specola è opera del celebre costruttore inglese Jesse Ramsden. Il raggio è di 8 piedi inglesi (244 cm), mentre il lembo è largo 4 pollici (circa 10 cm); in esso sono riportati due tipi di divisione: il bordo interno è graduato di 5 in 5 primi, secondo la divisione sessagesimale del circolo, mentre quello esterno è in 96 parti, ciascuna suddivisa in sedicesimi; sia la scala interna che quella esterna hanno l’origine alla base del raggio verticale. L’angolo veniva letto su entrambe le scale, convertendo la misura esterna in gradi grazie ad apposite tavole di corrispondenza. Questa procedura consentiva la riduzione degli eventuali errori di misura. Il cannocchiale, scorrevole lungo il lembo, ha lunghezza focale pari a 87 cm e obiettivo acromatico di 70 mm di apertura; sul piano focale giace il reticolo filare per il preciso puntamento della stella osservata.

82. Untitled1 Translate this page Puissant, Louis 448. Raab, CJC 480. Rabiqueau, Charles 425. ramsden, jesse 419.Reichard, Heinrich August Ottokar 485,623, 651. Reilly 664. Reynier, Louis 652. http://homepage.iprolink.ch/~moi/regaukt23.htm

Register Adam, Jean-Victor 489, 501, 502 Amrein, Kaspar Konstantin 430 Apianus, Petrus 378 Aristarch von Samos 456 Asselineau 492 Aubry, Charles 490, 491 Audiganne, Armand 478 Auger, D. 509 Aurach, Joseph Christian Auracher von 455 Auzout, Adrien 395 Bachofen 459, 460, 461 Bacler d'Albe, Louis Albert Ghislain 447 Balfour, Robert 382 Barillon, F. G. 551 Barnard, G. 494 Barrot, Odilon 552 Bassentin, Jacques 385 Bauernfeind, Carl Max von 470 Bavier, Simon 631 Beccaria, Giovanni Battista 418 Beckh, A. 636 Bel, Pierre 428, 663 Benedicti, Hieronymus 617 Bennewitz, Petrus 378 Bienewitz, Petrus 378 Binet 593 Bion, Nicolas 391, 407 Bodenehr, G. 614 Bole, M. 552 Bonne, Rigobert 422, 432 Bors, Johann Jakob 530 Boscovich, Ruggiero Giuseppe 412, 416 Bouguer, Pierre 403 Bradel 434 Bressanini 459, 460, 461 Brion 627 Buache, Phil. 658 Camus 396 Cassini de Thury, Jacques-Dominique 398 Cassini, Giovanni Domenico 389, 395 Cassini, Jacques 393, 395

83. Firstname Surname Events H Raadal 1 Marja Raatikka 9 Karen Rabe 1 Mitchell, ramsden, 25. Peter, ramsden, 27. Tessa, ramsden, 21. S, Ramstom, 1. Paul,Rand, 1. Will, Robbins, 1. Mark, Robers, 1. jesse, Roberston, 1. Alison, Roberton,1. D, Roberts, 4. http://bteahan.www1.dotnetplayground.com/Orienteering/ShowNames.asp?Letter=R

84. NL20 years earlier by Jeremiah Sisson, one of the foremost precision instrument makersin London but, incredibly enough, was redivided by jesse ramsden in 1782 on http://www.abdn.ac.uk/~nph126/items/nl20.htm

No. 20 Equatorial Telescope by Sisson and Ramsden This weighty 19 th John S Reid Back to Index Pages designed by Jill Macdonald Last updated 24 th August 1999

85. 600000 People Connected With European Royalty Father jesse Lee (17401831) Mother Susannah Johnson (1753-1840) Born1766 Christened Died 22 Nov 1857 Buried Spouse John ramsden Bt. http://www.e-familytree.net/f4995.htm

SPECULATIVE TREE . Most of the information in this tree is unverified by me - it's been traded freely on the internet. All corrections and additions would be greatfully accepted. This data changes often. If you've arrived from a search engine, it's likely you don't see the information you're looking for. If you go here you can use my index to find who you're looking for. Sign my guestbook or Send me an email It costs me $50.00 (US) a month to host e-familytree.net. It currently gets 3000 unique visitors a day. If only 10% of the people (300) donated .05 of their local currency each, I'd almost cover my costs. So if you can, please donate a bit to keep this place going! Thanks for your help! Rob Salzman e-familytree.net 4130 SW 117th Ave #415 Beaverton, OR 600000 people connected with European Royalty Husband Samuel Mcgowan Robertson Born: - Pickens Co., SC Christened: Died: Buried: Father: Thomas Lafayette Robertson (1840-1902) Mother: S Artemissa Clayton (1837-1907) Married: Wife Nancy Hutchinson Born: Christened: Died: Buried: Husband Olin Fulmer Hutchinson (details suppressed for this living person) Born: Christened: Died: Buried: Married: Wife Alma Rogers (details suppressed for this living person) Born: Christened: Died: Buried: Father: Henry Andrew Rogers ( - ) Mother: Fannie Smith (1898-1974) Husband Red Hutchinson (details suppressed for this living person)

86. AIP Historische Geräte Translate this page Universal-I. (Theodolit) mit Stativ (gesondert), 005, Achromatisches Fernrohr,2 1/2 Fuß, von jesse ramsden (Schwiegersohn von John Dollond), Baujahr 1787, http://www.aip.de/~lie/AUS/KAT/HG/hg.html

Den Anfang hat Gesamtschule Marie Curie , Potsdam) im Oktober 2000 gemacht, Stephan Schulze Hermann-von-Helmholtz Gymnasium erstellt. Im November 2001 hat Steven Meinhardt ( Gesamtschule Marie Curie Nr Beschreibung Abbildung Himmelsglobus auf Holzgestell von C. Adami 1873 Verlag D. Reimer Sternglobus von Johann Gabriel Doppelmaier Himmelsglobus von Ernst Schotte et Co Berlin Kl. Erdglobus im Holzgestell, 8 Leipziger Zoll, entworfen von M. Riedig, Berlin Richtungsfernrohr von Pistor Okular-Mikrometer von Otto Fennel (Cassel), 1889 Carl Bamberg , Nr. 55207 Sonnenprojektor mit Grundplatte im Transportkasten von Carl Bamberg , Nr. 10496 Pistor et P, 1851 Spiegelgalvanometer von Ruhstrat, Typ HSG1 Nr 212174 Spiegelgalvanometer von Ruhstrat, Typ HSG1 Nr 197081 Spiegelgalvanometer vom IfG Typ SPG2 st Nr 06914 Passagei. von Pistor und Schiek, Baujahr 1826 Okularspektroskop mit eingeblendeter Skala und einblendbarem Vergleichsspektrum von Carl Zeiss Jena, Nr 846 Libellen- Sextant Graukeil-Photometer von Otto Toepfer Zerlegbares Modell des menschlichen Auges im Holzkasten mit Beschreibung. August Oertling Mikrometer mit doppeltbrechendem Kristall nach Viktor Wellmann Heliotrop nach ; im Originalkasten von Carl Bamberg (Berlin-Friedenau), ca. 1890

87. Wiener Zeitung Suche Translate this page Dann reist er nach London, wo jesse ramsden die allerfeinsten Geräte herstellt.ramsden verbindet Linsenteleskope mit hochgenauen, weiten Kreisskalen. http://www.wienerzeitung.at/frameless/suche.htm?ID=9211&typ=Extra

88. I16266 Joshua Scott BRADY (Private - ) _William EWING _+ _John EWING _ _Anna SHANNON jesse EWING _Phebe DAVIDSON _ INDEX. HOME Joseph ramsden. http://www.netcr.com/pub/djw/d0012/g0000007.html

89. Ramsden Family History Page jesse ramsden (17351800). HARRY ramsden FISH AND CHIPS (UK). http://www.stephenramsden.com/ramsden.html

t THE RAMSDEN's JESSE RAMSDEN (1735-1800) HARRY RAMSDEN FISH AND CHIPS (UK)

90. Tumbling Stone 1 - The Night Piazzi Discovered Ceres instruments. jesse ramsden was an instrumentmaker without peer, buthe was notorious for failing to produce on time. Piazzi persuaded http://spaceguard.ias.rm.cnr.it/tumblingstone/issues/num1/piazzi.htm

The night Piazzi discovered Ceres by Nanni Riccobono Astronomer G. Piazzi Piazzi was born in 1746 in Valtellina (which at that time, was part of Switzerland). As a young man, Piazzi joined the Theatine Order, and afterwards taught mathematics in a number of Italian cities. In 1780 he was invited to take the chair of higher mathematics at the Academy of Palermo. Arriving at Palermo, Piazzi, although inexperienced in astronomy, expressed a wish to found an astronomical observatory: Palermo was further south than any existing European observatory and so offered access to regions of the sky inaccessible elsewhere. Piazzi accordingly set off for England where he might obtain good instruments. Jesse Ramsden was an instrument-maker without peer, but he was notorious for failing to produce on time. Piazzi persuaded him to attempt a 5ft vertical circle of unique design. The circle, which has been described as ``a masterpiece of eighteenth-century technology'', was twice abandoned by Ramsden, and he completed it eventually in August 1789 only because Piazzi himself was present in London - indeed, in Ramsden's workshop, and quite literally breathing down Ramdsen's neck as the work proceeded. The circle gave readings in azimuth by micrometer microscope, and readings in altitude by two diametrically opposed microscopes. The divisions on the circles were illuminated by an inclined silver mirror fixed to each microscope, and the wires in the telescope eyepiece by transmitting light from a small lamp through the hollow tube-axis.

91. Torna Alla Pagina Principale Torna Alla Pagina Precedente MUSEO Translate this page In particolare l'altazimutale del celeberrimo jesse ramsden, il più abile costruttoredi strumenti della seconda metà del XVIII secolo, costituisce un unicum http://www.guidastudentepalermo.net/musei/astrono/

MUSEO DELL'OSSERVATORIO ASTRONOMICO Osservatorio Astronomico di Palermo G.S. Vaiana Dipartimento di Scienze Fisiche ed Astronomiche Visualizza le immagini La Collezione di Antichi Strumenti dell'Osservatorio Astronomico di Palermo L'Osservatorio Astronomico di Palermo, occupa, sin dal 1790, alcuni locali del Real Palazzo concessi dal Re Ferdinando di Borbone a Giuseppe Piazzi (1746-1826), fondatore e primo Direttore dell'Osservatorio, per stabilirvi l'osservatorio e darvi l'abitazione al Professore. La Specola propriamente detta tu eretta sulla Torre di Santa Ninfa perché riconosciuta come la più adatta per l'elevazione del sito e per la sodezza delle fonda menta. Giuseppe Piazzi era appena ritornato (agosto 1789) da un soggiorno di due anni in Francia ed in Inghilterra dove si era recato per acquistare gli strumenti necessari ad istabilire codest'Osservatorio che certamente potrà essere de' migliori. Ed in effetti così tu, poiché gli strumenti acquistati da Piazzi, che costituiscono il nucleo più antico della collezione, furono tutti commissionati alle più celebri officine inglesi. In particolare l'altazimutale del celeberrimo Jesse Ramsden, il più abile costruttore di strumenti della seconda metà del XVIII secolo, costituisce un unicum, uno strumento di concezione nuovissima, considerato il prototipo di una nuova generazione di strumenti astronomici, gli strumenti a scala circolare, che soppianteranno nel corso del secolo successivo i tradizionali quadranti di cui ci si era serviti durante tutto il corso del XVIII secolo. La sua importanza per la storia dell'Astronomia e dello sviluppo della tecnologia dei grandi strumenti astronomici è oggi universalmente riconosciuta. L'altazimutale di Ramsden tu collocato nella

92. BAR101 philosphical instrument maker at 199 Piccadilly. He took over the businessof jesse ramsden in Piccadilly when ramsden died in 1800. http://www.allan-smith-antique-clocks.co.uk/Barometers/Bar101/BAR101.htm

Barometer by Berge of London M. (Matthew) Berge recorded working in 1800 (died 1819) was an optical, mathematical and philosphical instrument maker at 199 Piccadilly. He took over the business of Jesse Ramsden in Piccadilly when Ramsden died in 1800. Berge made stick and marine barometers and some are signed "Berge London, late Ramsden". He was, no doubt, trading on the very high reputation that Ramsden had built up over the years "Flat to the wall" bow front stick barometers of the late 18th and early 19th century are among the finest produced and most sought after. This is one such. Height: 38.25" (97cms)

93. OPE-MAT - Historique Translate this page Rosanes, Jakob Picard, Jean Rajagopal, C Rosenhain, Johann Pieri, Mario Ramanujan,Srinivasa Roth, Leonard Pincherle, Salvatore ramsden, jesse Routh, Edward http://www.gci.ulaval.ca/PIIP/math-app/Historique/mat.htm

A Abel , Niels Akhiezer , Naum Anthemius of Tralles Abraham bar Hiyya al'Battani , Abu Allah Antiphon the Sophist Abraham, Max al'Biruni , Abu Arrayhan Apollonius of Perga Abu Kamil Shuja al'Haitam , Abu Ali Appell , Paul Abu'l-Wafa al'Buzjani al'Kashi , Ghiyath Arago , Francois Ackermann , Wilhelm al'Khwarizmi , Abu Arbogast , Louis Adams , John Couch Albert of Saxony Arbuthnot , John Adelard of Bath Albert , Abraham Archimedes of Syracuse Adler , August Alberti , Leone Battista Archytas of Tarentum Adrain , Robert Albertus Magnus, Saint Argand , Jean Aepinus , Franz Alcuin of York Aristaeus the Elder Agnesi , Maria Alekandrov , Pavel Aristarchus of Samos Ahmed ibn Yusuf Alexander , James Aristotle Ahmes Arnauld , Antoine Aida Yasuaki Amsler , Jacob Aronhold , Siegfried Aiken , Howard Anaxagoras of Clazomenae Artin , Emil Airy , George Anderson , Oskar Aryabhata the Elder Aitken , Alexander Angeli , Stefano degli Atwood , George Ajima , Chokuyen Anstice , Robert Richard Avicenna , Abu Ali B Babbage , Charles Betti , Enrico Bossut , Charles Bachet Beurling , Arne Bouguer , Pierre Bachmann , Paul Boulliau , Ismael Bacon , Roger Bhaskara Bouquet , Jean Backus , John Bianchi , Luigi Bour , Edmond Baer , Reinhold Bieberbach , Ludwig Bourgainville , Louis Baire Billy , Jacques de Boutroux , Pierre Baker , Henry Binet , Jacques Bowditch , Nathaniel Ball , W W Rouse Biot , Jean-Baptiste Bowen , Rufus Balmer , Johann Birkhoff , George Boyle , Robert Banach , Stefan Bjerknes, Carl

94. Administrative Information Bob Thompson, Glendale CC. Betsy Ivester, Scottsdale CC. Julie ramsden, ASU West.September 21, 2000. ASU Main. jesse Alberts, ASU Main. jesse Alberts, ASU Main. http://az.transfer.org/cas/atass/admin/atfcalendar0001.htm

ATF Meetings for 2000-01 DATE ATF SITE HOST CHAIR ATAC Member August 29, 2000 GEATF, 10:00 a.m. - 2:00 p.m. Coconino Community College Coconino Community College N/A September 15, 2000 Geology Glendale CC Bob Thompson, Glendale CC Betsy Ivester, Scottsdale CC Julie Ramsden, ASU West September 21, 2000 Hospitality -continues to Sept 22 NAU Paul Weiner, NAU Janice Pratt, CAC Patrick Martin or Danye Johnson, NAU September 22, 2000 English ASU-East David Schwalm, ASU East David Schwalm, ASU East Zoila Gamero de Tovar, ASU September 22, 2000 TSO meeting, 8:00 a.m. - 10 a.m.; Academic Advising, 10:30 a.m. - 2:30 p.m. NAU NAU N/A September 29, 2000 Engineering Scottsdale CC Keith Worth, SCC Keith Worth, SCC Bill Fee, UA September 29, 2000 Languages ASU Main Gary Tipton and Teresa Valdivieso, ASU Main Melissa Fitch, UA Zoila Gamero de Tovar, ASU October 6, 2000 Art NAU Helaine McLain, NAU Alan Peterson, Coconino Patrick Martin, NAU October 6, 2000 Communication ASU Main Jesse Alberts, ASU Main Jesse Alberts, ASU Main Roger Johnson, Mohave CC October 6, 2000

95. West Sea Co. TELESCOPES & OPTICS Catalog Page 21 Born in 1759, William was apprenticed to the legendary jesse ramsden, and set uphis own practice as an optician and nautical instrument maker at 277 The Strand http://www.westsea.com/tsg3/catlocker/cat21chart.htm

West Sea Company Catalog Page 21 Click on photos for larger images. Prices are in BOLD If shown, use the Price On Request button to request pricing information. Click for ordering details. 21.30 MARINE SURVEYING INSTRUMENT. The renown instrument making family of Cary, London dates to 1765. The brief partnership of William Cary and Henry Porter was established in 1890. IN BOX LABEL SIGNATURE BOX 21.29 IMPORTANT EARLY TELESCOPE. Museum quality, late 1600's or very early 1700's mariner's 3 draw telescope signed "Oliuo, Venezia" on the textured vellum main tube. This exceptional early telescope is constructed of vellum (hard paper suggestive of lambskin) with an embossed floral design fitted with end caps of decoratively turned horn with a telling early style "nipple" eye cup. The original simple optics are of the monochromatic type with turned boxwood retainers, producing a magnified upright image with a narrow field of view. Each of the three draws is marked with a ring at the point of focus to facilitate use. Amazingly both the objective and eyepiece screw-on dust covers are still present! These covers consist of turned horn caps which thread on to their respective ends. This incredible telescope is in an outstanding state of preservation for its age. It evidences expected wear and patina from use. The horn rings are sound and exhibit virtually no worming as is typical of such early material. This telescope measures exactly one foot long when closed and extends to 31 inches long at infinity. An extremely desirable early mariner's telescope with origins in the cradle of early navigation Venice, Italy!

96. Ramsden, Jessé Lien vers la nouvelle version des pages web du patrimoine ramsden, Jessé. (17301800). ramsden, Jessé http://www.polytechnique.fr/bcx/patrimoine/collectionhomme/BioRamsden.html

Lien vers la nouvelle version des pages web du patrimoine : sont des chefs-d'oeuvre de construction.

97. Ramsden, Jessé ramsden, Jessé. (17301800). Opticien anglais, né près de Halifax (comté d'York) en 1735, mort à Brighton en 1800. http://www.patrimoine.polytechnique.fr/collectionhomme/BioRamsden.html

98. Story: Jesse's Gift To Bill Gates - ZDNet jesse's Gift to Bill Gates. jesse Berst, Editorial Director ZDNet AnchorDeskFriday, December 15, 2000, Talk back! People often accuse http://www.zdnet.com/anchordesk/stories/story/0,10738,2664965,00.html

Reviews Hardware Software Personal Tech ... Prices Jesse's Gift to Bill Gates Jesse Berst, Editorial Director ZDNet AnchorDesk Friday, December 15, 2000 People often accuse me of picking on Bill Gates. So much so that I have to defend myself now and again. Click for more But since it's the season of giving, I'll declare my Christmas wishes for the man I so routinely mock. I'll tell you about the good I think he's done and just one small thing that I wish for him to get this holiday season. My apologies in advance to Charles Dickens. WHAT BILL'S GOT It's a tired question: What do you get the man who's got everything? There may be no one for whom that is more true than Bill Gates. He's got a lot: A $65 billion fortune Click for more A $100 million home on Lake Washington Click for more 40,000 bright employees Click for more Offices in 59 countries A great set of bridge partners Click for more WHAT HE NEEDS What Gates may not have, I'm sorry to say, is a conscience. If I had the power to do it, I'd give Bill Gates a trio of visitations a la Scrooge. I know what you're going to say. Bill Gates created the largest charitable foundation on the planet. For that, he and his wife Melinda should be heartily applauded. Click for more Bill Gates is the most important philanthropist of the last 100 years.

99. ”ü¯’¬@¯‚̃f[ƒ^ƒx[ƒX The summary for this Japanese page contains characters that cannot be correctly displayed in this language/character set. http://www.town.bisei.okayama.jp/stardb/dat/jinmei/dat_j_ra_02.html

¡ l–¼Ž«“Ty‚çz ƒy[ƒW@ ‚P ‚Q ƒ‰ƒbƒZƒ‹ Lassell, William i1799-1880j ƒgƒŠƒgƒ“ ‚ð”­Œ©D‚³‚ç‚ɁC1851”N‚ɂ́C “V‰¤¯ ‚̉q¯ƒAƒŠƒGƒ‹‚ƃEƒ“ƒuƒŠƒGƒ‹‚ð”­Œ©‚µ‚Ä‚¢‚éD ƒ‰ƒh[ Radau,J.C.R. i1835-1911j ƒhƒCƒc¶‚Ü‚ê‚̃tƒ‰ƒ“ƒX‚Ì“V•¶ŠwŽÒD‰¹‹¿ŠwC‘¾—z‚ÌŒ¤‹†‚Å’m‚ç‚ê‚éD‘¾—z‚ÌŽ©“]ŽüŠú‚ªˆÜ“x‚ňႤ‚±‚Æ‚ð”­Œ©D ‘å‹C· ƒ‰ƒ”ƒFƒ‹ Lovell,Alfred Charles Bernard i1913-@@j ƒCƒMƒŠƒX‚Ì“d”g“V•¶ŠwŽÒDƒŒ[ƒ_[‚ð—p‚¢‚½“V•¶ŠwDP¯‚̃tƒŒƒA‚É‚Æ‚à‚È‚¤“d”gƒo[ƒXƒg‚ðÅ‰‚ÉŠÏ‘ªD ƒWƒ‡ƒhƒŒƒ‹ƒoƒ“ƒN“V•¶‘ä ‚É‚¨‚¯‚é“d”g“V•¶Šw‚̃Š[ƒ_[‚Æ‚µ‚Ä‹ÆÑ‚ð‚ ‚°‚½D ƒ‰ƒvƒ‰ƒX Laplace,Pierre Simon,Marquis de i1749-1827j ƒJƒ“ƒg ƒ‰ƒ“ƒxƒ‹ƒg Lambert, Johann Heinrich i1728-1777j ƒ‰ƒ“ƒxƒ‹ƒg‚Í•n‚µ‚¢‰Æ‚̏og‚Å‚ ‚èC‚Ù‚Æ‚ñ‚Ç“ÆŠw‚ÅŠw–â‚ðC‚߁C‹³Žt‚â•ë‹LŒW‚È‚Ç—lX‚ȐE‹Æ‚ɂ‚«‚È‚ª‚ç—]‰É‚ɉȊw‚ðŠy‚µ‚ñ‚¾D1764”N‚Ƀxƒ‹ƒŠƒ“‚ɈڂèCƒtƒŠ[ƒhƒŠƒbƒq‘剤‚É‚æ‚Á‚ăxƒ‹ƒŠƒ“ƒAƒJƒfƒ~[‚̉ïˆõ‚Æ‚È‚Á‚½D ƒ‰ƒ€ƒXƒfƒ“ Ramsden, Jesse i1735-1800j ƒCƒMƒŠƒX‚ÌŠÏ‘ª‹@Ší»ìŽÒDƒo[ƒgƒ“‚Ì’íŽqD ƒVƒ‡[ƒg ‚Ì–]‰“‹¾‚̉ü—ǁD1775”N1/2•b‚̌덷‚ÅŠp“x‚ß‚à‚è‚ð‚«‚´‚ށC–ڐ·‚荏ˆó‹@‚ð”­–¾D1795”N‚Ɂu‰ÈŠw‘•’u‚̉ü—Ç‚Æ”­–¾v‚É‚æ‚èƒRƒvƒŠ[Eƒƒ_ƒ‹‚ðŽóÜDƒ‰ƒ€ƒXƒfƒ“ÚŠá‹¾”­–¾D ƒ‰ƒ‚ƒ“ƒg Lamont,J.von

100. L'EVOLUZIONE DEL TELESCOPIO A RIFLESSIONE http://www.orsapa.it/saggi/evtele.htm

L'EVOLUZIONE DEL TELESCOPIO A RIFLESSIONE: DA NEWTON A LORD ROSSE di Fredi De Maria Fig. 1: Sir Isaac Newton Nuova Teoria sulla Luce e i Colori presentata alla Royal Society nel 1672, verrà definitivamente ed organicamente esposta, trent'anni più tardi, nel trattato " Optics ", dato alle stampe nel 1704. Allorché mise mano a tali esperimenti, Newton era ormai pronto ad andare oltre Cartesio e Keplero: perfettamente padrone del trattamento matematico della luce, come molti altri scienziati suoi contemporanei era estremamente interessato al perfezionamento delle lenti, per le quali, allo scopo di correggerne l'aberrazione sferica, Cartesio stesso aveva correttamente proposto curvature asferiche, e più precisamente paraboliche. Newton seguì la stessa via, e costruì diversi cannocchiali basati sulla rifrazione. Ma le ragioni che gli avevano suggerito l'acquisto di quel prisma, e gli esperimenti che ne seguirono, lo persuasero ad accantonare le sue ricerche sulle lenti. Lo spazio non consente di entrare nel dettaglio del suo racconto dell'esperimento grazie al quale pervenne alla comprensione e alla descrizione della natura della luce; quel che conta è che egli si rese conto dell'impossibilità di concentrare esattamente la luce bianca in un punto focale mediante una lente, dato che la distanza focale risultava diversa per ciascuno dei colori componenti la luce bianca stessa: di qui le fastidiose frange colorate (iridazioni) che si osservavano nelle immagini fornite da cannocchiali e microscopi. Benché le lenti asferiche fossero in grado di correggere l'aberrazione sferica, esse non avrebbero potuto fornire alcun aiuto nei confronti di quelle frange.

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

Page 5     81-100 of 100    Back | 1  | 2  | 3  | 4  | 5