{"id":6719,"date":"2018-09-19T13:42:42","date_gmt":"2018-09-19T13:42:42","guid":{"rendered":"http:\/\/uni.hi.is\/einar\/?p=6719"},"modified":"2018-09-19T13:42:42","modified_gmt":"2018-09-19T13:42:42","slug":"halastjornur-fyrr-og-nu-2-atjanda-og-nitjanda-old","status":"publish","type":"post","link":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/?p=6719","title":{"rendered":"Halastj\u00f6rnur fyrr og n\u00fa &#8211; 2. \u00c1tj\u00e1nda og n\u00edtj\u00e1nda \u00f6ld"},"content":{"rendered":"<p><span style=\"font-size: 10pt\">\u00deessi f\u00e6rsla er \u00f6nnur \u00ed r\u00f6\u00f0inni af fj\u00f3rum og beint framhald af \u00feeirri fyrstu:<\/span><em><span style=\"font-size: 10pt\"> Halastj\u00f6rnur fyrr og n\u00fa &#8211; 1. Fr\u00e1 mi\u00f0\u00f6ldum til loka sautj\u00e1ndu aldar.<\/span><\/em><\/p>\n<p>\u00c1 \u00e1tj\u00e1ndu \u00f6ld og fyrri hluta \u00feeirrar n\u00edtj\u00e1ndu snerust ranns\u00f3knir \u00e1 halastj\u00f6rnum fyrst og fremst um leitina a\u00f0 n\u00fdjum lei\u00f0um til \u00feess a\u00f0 \u00e1kvar\u00f0a brautir \u00feeirra me\u00f0 sem mestri n\u00e1kv\u00e6mni. Til \u00feess \u00feurfti b\u00e6\u00f0i vanda\u00f0ar athuganir og n\u00fdjar og betri reiknia\u00f0fer\u00f0ir.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-6958 aligncenter\" src=\"http:\/\/uni.hi.is\/einar\/files\/2018\/08\/comet1737-262x300.jpg\" alt=\"\" width=\"444\" height=\"509\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/comet1737-262x300.jpg 262w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/comet1737-893x1024.jpg 893w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/comet1737-768x880.jpg 768w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/comet1737-1340x1536.jpg 1340w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/comet1737-1787x2048.jpg 1787w\" sizes=\"auto, (max-width: 444px) 100vw, 444px\" \/><\/p>\n<p>Eins og fram kom \u00ed fyrstu f\u00e6rslunni, nota\u00f0i <a href=\"https:\/\/en.wikipedia.org\/wiki\/Isaac_Newton\">Newton<\/a> fleygbogan\u00e1lgun og r\u00famfr\u00e6\u00f0ilegar reiknia\u00f0fer\u00f0ir til a\u00f0 \u00e1kvar\u00f0a <a href=\"https:\/\/en.wikipedia.org\/wiki\/Great_Comet_of_1680\">braut halastj\u00f6rnunnar 1680<\/a> \u00fat fr\u00e1 \u00feremur sta\u00f0arm\u00e6lingum. Hi\u00f0 sama ger\u00f0i <a href=\"https:\/\/en.wikipedia.org\/wiki\/Edmond_Halley\">Halley<\/a> vi\u00f0 s\u00edna brautarreikninga, en vegna \u00feess hversu fl\u00f3knir reikningarinir voru, lei\u00f0 talsver\u00f0ur t\u00edmi \u00fear til a\u00f0rir st\u00e6r\u00f0fr\u00e6\u00f0ilegir l\u00e6rd\u00f3msmenn n\u00e1\u00f0u t\u00f6kum \u00e1 \u00feeim.\u00a0 M\u00f6nnum var\u00f0 \u00fev\u00ed flj\u00f3tlega lj\u00f3st, a\u00f0 frekari \u00farb\u00f3ta var \u00fe\u00f6rf og \u00e1 seinni hluta \u00e1tj\u00e1ndu aldar endurb\u00e6ttu og \u00fatv\u00edkku\u00f0u spekingarnir <a href=\"https:\/\/en.wikipedia.org\/wiki\/Leonhard_Euler\">L. Euler<\/a>, <a href=\"https:\/\/en.wikipedia.org\/wiki\/Johann_Heinrich_Lambert\">J. H. Lambert<\/a>, <a href=\"https:\/\/en.wikipedia.org\/wiki\/Joseph-Louis_Lagrange\">J. L. Lagrange<\/a>, <a href=\"https:\/\/en.wikipedia.org\/wiki\/Pierre-Simon_Laplace\">P. S. Laplace<\/a>, <a href=\"https:\/\/de.wikipedia.org\/wiki\/Heinrich_Wilhelm_Olbers\">H. W. Olbers<\/a> og fleiri a\u00f0fer\u00f0 Newtons, \u00feannig a\u00f0 h\u00e6gt v\u00e6ri a\u00f0 frumreikna brautir halastjarna \u00ed fleygbogan\u00e1lgun \u00e1n mj\u00f6g fl\u00f3kinna og t\u00edmafrekra r\u00famfr\u00e6\u00f0ilegra a\u00f0fer\u00f0a. Jafnframt voru \u00fer\u00f3a\u00f0ar a\u00f0fer\u00f0ir til a\u00f0 taka tillit til truflandi \u00feyngdar\u00e1hrifa reikistjarnanna.\u00a0 Flj\u00f3tlega upp \u00far aldam\u00f3tunum 1800 fann <a href=\"https:\/\/en.wikipedia.org\/wiki\/Carl_Friedrich_Gauss\">C. F. Gauss<\/a> svo almenna a\u00f0fer\u00f0 til a\u00f0 finna hva\u00f0a keilusni\u00f0s-braut sem er \u00fat fr\u00e1 \u00feremur sta\u00f0arm\u00e6lingum.<\/p>\n<ul>\n<li>J. M. Vinter Hansen, 1944: <a href=\"http:\/\/adsbit.harvard.edu\/\/full\/1944PA.....52..370H\/0000370.000.html\">The Orbits of Comets.<\/a><\/li>\n<li>D. Teets og K. Whitehead, 1999: <a href=\"http:\/\/people.math.yorku.ca\/pcgibson\/math4400\/math4400files\/Ceres.pdf\">The Discovery of Ceres: How Gauss Became Famous.<\/a><\/li>\n<li>W. Olbers, 1797:\u00a0 <a href=\"https:\/\/books.google.is\/books?id=8ptSAAAAcAAJ&amp;source=gbs_navlinks_s\">Abhandlung \u00fcber die leichteste und bequemste Methode die Bahn eines Cometen zu berechnen.<\/a> (\u00fatg\u00e1fa Enckes fr\u00e1 1847).<\/li>\n<li>C. F. Gauss, 1809: <a href=\"https:\/\/books.google.is\/books?id=ORUOAAAAQAAJ&amp;source=gbs_navlinks_s\">Theoria motus corporum coelestium in sectionibus conicis solem ambientium.<\/a><\/li>\n<li>T. Bugge, 1796:\u00a0 <a href=\"https:\/\/books.google.is\/books?id=eoVaAAAAcAAJ&amp;hl=is&amp;source=gbs_navlinks_s\">De f\u00f8rste Grunde til den sph\u00e6riske og theoretiske Astronomie, samt den mathematiske Geographie.<\/a> (bls. 194-209)<\/li>\n<li>J. E. Bode, 1808: <a href=\"https:\/\/books.google.is\/books?id=m3D9ieNduNoC&amp;source=gbs_navlinks_s\">Erl\u00e4uterung der Sternkunde und der dazu geh\u00f6rigen Wissenschaften<\/a>\u00a0 (bls. 222-282).<\/li>\n<\/ul>\n<p>Reikningarnir sn\u00faast um \u00fea\u00f0 a\u00f0 \u00e1kvar\u00f0a svokalla\u00f0ar <a href=\"https:\/\/en.wikipedia.org\/wiki\/Orbital_elements\">grunnst\u00e6r\u00f0ir brautarinnar<\/a> (stundum kalla\u00f0ar <em>brautarstikar<\/em>) \u00fat fr\u00e1 st\u00f6\u00f0u halastj\u00f6rnunnar \u00e1 stj\u00f6rnuhimninum \u00e1 \u00feremur mismunandi t\u00edmum. Gengi\u00f0 er \u00fat fr\u00e1 \u00fev\u00ed a\u00f0 grunnbrautin s\u00e9 <a href=\"https:\/\/en.wikipedia.org\/wiki\/Conic_section\">keilusni\u00f0<\/a>, \u00fea\u00f0 er sporbaugur (ellipsa), fleygbogi (parab\u00f3la) e\u00f0a glei\u00f0bogi (h\u00fdperb\u00f3la), me\u00f0 s\u00f3lina \u00ed brennipunkti. \u00deessi forsenda er \u00ed samr\u00e6mi vi\u00f0 hina fr\u00e6gu ni\u00f0urst\u00f6\u00f0u Newtons um <a href=\"https:\/\/en.wikipedia.org\/wiki\/Kepler_orbit\">hreyfingar \u00ed s\u00f3lkerfinu<\/a>, sem r\u00e6tt var um \u00ed s\u00ed\u00f0ustu f\u00e6rslu. B\u00e6\u00f0i sporbaug og glei\u00f0boga m\u00e1 n\u00e1lga me\u00f0 fleygboga umhverfis s\u00f3ln\u00e1nd, sem einfaldar frumreikningana verulega. Frekari m\u00e6lingar \u00e1kvar\u00f0a brautina betur og \u00ed framhaldinu er jafnframt beitt svok\u00f6llu\u00f0um <a href=\"https:\/\/en.wikipedia.org\/wiki\/Perturbation_(astronomy)\">truflanareikningi<\/a>. til a\u00f0 meta \u00e1hrif reikistjarnanna \u00e1 braut halastj\u00f6rnunnar.<\/p>\n<figure id=\"attachment_5371\" aria-describedby=\"caption-attachment-5371\" style=\"width: 484px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-5371\" src=\"http:\/\/uni.hi.is\/einar\/files\/2018\/07\/OrbElem-300x270.png\" alt=\"\" width=\"484\" height=\"435\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/07\/OrbElem-300x270.png 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/07\/OrbElem.png 555w\" sizes=\"auto, (max-width: 484px) 100vw, 484px\" \/><figcaption id=\"caption-attachment-5371\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">Grunnst\u00e6r\u00f0ir brautar halastj\u00f6rnu (og reyndar s\u00e9rhvers hnattar \u00ed s\u00f3lkerfinu): \u00c1 myndinni t\u00e1knar gr\u00e1a sv\u00e6\u00f0i\u00f0 (plane of reference) jar\u00f0brautarplani\u00f0 me\u00f0 s\u00f3lina \u00ed mi\u00f0junni. Rau\u00f0a l\u00ednan til h\u00e6gri (reference direction) stefnir \u00e1 vorpunktinn\u00a0<span style=\"font-size: 8pt\"><big>\u2648\ufe0e<\/big><\/span>. Svarti ferillinn sem afmarkar gula sv\u00e6\u00f0i\u00f0 er braut (orbit)\u00a0 halastj\u00f6rnunnar um s\u00f3lina. \u00cd \u00feessu tilviki gengur halastjarnan (celestial body) rangs\u00e6lis eftir brautinni, fr\u00e1 okkur s\u00e9\u00f0. Fj\u00f3lubl\u00e1a l\u00ednan tengir saman s\u00f3lina og s\u00f3ln\u00e1ndarpunkt halastj\u00f6rnunnar. Skur\u00f0l\u00edna jar\u00f0brautarplansins og brautarplans halastj\u00f6rnunnar s\u00e9st greinilega \u00e1 myndinni. Halastj\u00f6rnubrautin sker jar\u00f0brautarplani\u00f0 \u00ed tveimur gagnst\u00e6\u00f0um punktum: rishn\u00fatnum (ascending node) og sighn\u00fatnum (descending node).\u00a0 &#8211;\u00a0 G<em>runnst\u00e6r\u00f0ir<\/em> brautarinnar eru sex, og eru fj\u00f3rar \u00feeirra s\u00fdndar \u00e1 myndinni, \u00fe.e. hornin\u00a0 <strong>\u03a9<\/strong> = <em>s\u00f3lbaugslengd rishn\u00fats<\/em> (longitude of ascending node), <strong>i<\/strong> =\u00a0 <em>brautarhalli<\/em> (inclination),\u00a0 <strong>\u03bd<\/strong> = <em>r\u00e9tt brautarhorn<\/em> (true anomaly) og\u00a0<strong>\u03c9<\/strong> = <em>st\u00f6\u00f0uhorn s\u00f3ln\u00e1ndar<\/em> (argument of periapsis). S\u00ed\u00f0ustu tv\u00e6r grunnst\u00e6r\u00f0irnar eru svo <strong>e<\/strong> = <em>mi\u00f0skekkj<\/em>a (eccentricity) og <strong>a<\/strong> = <em>h\u00e1lfur lang\u00e1s<\/em> (semimajor axis) halastj\u00f6rnubrautarinnar.\u00a0 &#8211;\u00a0\u00a0 Mynd: Wikipedia.<br \/><\/span><\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<h3 style=\"text-align: center\"><span style=\"font-size: 14pt\">\u00ddmis verk um halastj\u00f6rnur, \u00e6tlu\u00f0 \u00edslenskri al\u00fe\u00fd\u00f0u \u00e1 18. og 19. \u00f6ld<\/span><\/h3>\n<p>\u00dea\u00f0 var ekki fyrr en vel var li\u00f0i\u00f0 \u00e1 \u00edslenska uppl\u00fdsingart\u00edmann, sem fyrstu fr\u00e6\u00f0sluritin um stj\u00f6rnufr\u00e6\u00f0i bygg\u00f0a \u00e1 s\u00f3lmi\u00f0jukenningunni og heimsmynd Newtons t\u00f3ku a\u00f0 birtast h\u00e9r \u00e1 landi.<\/p>\n<p style=\"text-align: center\"><em>Lok \u00e1tj\u00e1ndu aldar:<\/em><\/p>\n<ul>\n<li>Hannes Finnson, 1797: <a href=\"http:\/\/baekur.is\/bok\/000160591\/2\/57\/Kvoldvokurnar_Bindi_2_Bls_57\">Um halastj\u00f6rnur<\/a>. V\u00f6ndu\u00f0 hugvekja um halstj\u00f6rnufr\u00e6\u00f0i s\u00edns t\u00edma.<\/li>\n<li>Magn\u00fas Stephensen, 1797: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=970311\">Vorir s\u00f3lheimar<\/a> (halastj\u00f6rnur: bls. 62-64).<\/li>\n<li><a href=\"https:\/\/da.wikipedia.org\/wiki\/Peter_Frederik_Suhm\">P.F.Suhm<\/a>\u00a0 og J\u00f3n J\u00f3nsson, 1798: <a href=\"http:\/\/baekur.is\/bok\/000380271\/0\/138\/Sa_gudlega_thenkjandi_Bls_138\">S\u00e1 gu\u00f0lega \u00feenkjandi n\u00e1tt\u00farusko\u00f0ari<\/a> (halastj\u00f6rnur: bls. 118-120).\u00a0 Ne\u00f0anm\u00e1lsgreinar J\u00f3ns eru mikilv\u00e6gur hluti \u00feessa verks og \u00fev\u00ed er hann skr\u00e1\u00f0ur h\u00e9r sem me\u00f0h\u00f6fundur.<\/li>\n<\/ul>\n<figure id=\"attachment_7610\" aria-describedby=\"caption-attachment-7610\" style=\"width: 273px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-7610\" src=\"http:\/\/uni.hi.is\/einar\/files\/2018\/09\/HannesFinnsson.jpg\" alt=\"\" width=\"273\" height=\"375\" \/><figcaption id=\"caption-attachment-7610\" class=\"wp-caption-text\">Hannes Finnsson biskup skrifa\u00f0i fyrstu \u00edslensku fr\u00e6\u00f0slugreinina um halastj\u00f6rnur, sem kom \u00e1 prenti.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p style=\"text-align: center\"><em>Mi\u00f0bik n\u00edtj\u00e1ndu aldar:<\/em><\/p>\n<ul>\n<li><a href=\"https:\/\/da.wikipedia.org\/wiki\/G.F._Ursin\">G. F. Ursin<\/a>, 1842: <a href=\"http:\/\/baekur.is\/bok\/000402495\/0\/127\/Stjornufraedi__lett_og_handa_Bls_127\">Stj\u00f6rnufr\u00e6\u00f0i<\/a> (halastj\u00f6rnur: bls. 115-135). V\u00f6ndu\u00f0 umfj\u00f6llun, bygg\u00f0 \u00e1 \u00feekkingu stjarnv\u00edsindamanna \u00e1 fyrri hluta 19. aldar. Ekki skemmir \u00fea\u00f0 fyrir, a\u00f0 \u00fe\u00fd\u00f0andi b\u00f3karinnar var J\u00f3nas Hallgr\u00edmsson.<\/li>\n<\/ul>\n<p style=\"text-align: center\"><em>S\u00ed\u00f0asti fj\u00f3r\u00f0ungur n\u00edtj\u00e1ndu aldar:<\/em><\/p>\n<ul>\n<li>\u00de\u00f3rarinn B\u00f6\u00f0varsson, 1874: <a href=\"https:\/\/archive.org\/details\/Lestrarbokhandaa000241121v0THoraReyk\">Lestrarb\u00f3k handa al\u00fe\u00fd\u00f0u \u00e1 \u00cdslandi<\/a> (halastj\u00f6rnur: bls. 137).<\/li>\n<li>P\u00e1ll J\u00f3nsson, 1883: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=2041721\">Halastj\u00f6rnur<\/a>.<\/li>\n<li>\u00deorvaldur Thoroddsen, 1883: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?gegnirId=000587484\">Halastj\u00f6rnur og stj\u00f6rnuhr\u00f6p<\/a>.<\/li>\n<li>Bj\u00f6rn Jensson, 1889: <em>Stj\u00f6rnufr\u00e6\u00f0i<\/em> (halastj\u00f6rnur: bls. 45-50).<\/li>\n<li><a href=\"https:\/\/fr.wikipedia.org\/wiki\/Henri_de_Parville\">H. de Parville<\/a>, 1891-93: <em>Hvers vegna?-Vegna \u00feess!<\/em> (halastj\u00f6rnur: bls. 210-212).<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h3 style=\"text-align: center\"><span style=\"font-size: 14pt\">Nokkrar \u00e1hugaver\u00f0ar halastj\u00f6rnur \u00e1 \u00e1tj\u00e1ndu \u00f6ld<\/span><\/h3>\n<figure id=\"attachment_5801\" aria-describedby=\"caption-attachment-5801\" style=\"width: 392px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-5801\" src=\"http:\/\/uni.hi.is\/einar\/files\/2018\/07\/Maupertuis1732-200x300.jpg\" alt=\"\" width=\"392\" height=\"588\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/07\/Maupertuis1732-200x300.jpg 200w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/07\/Maupertuis1732.jpg 532w\" sizes=\"auto, (max-width: 392px) 100vw, 392px\" \/><figcaption id=\"caption-attachment-5801\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">\u00c1 meginlandi Evr\u00f3pu voru \u00fea\u00f0 Frakkar, sem fyrstir t\u00f3ku hugmyndir Newtons til til umr\u00e6\u00f0u og alvarlegrar umfj\u00f6llunar. \u00deessi skemmtilega mynd af fj\u00f6lda s\u00f3lkerfa me\u00f0 reikistj\u00f6rnum, tunglum og halastj\u00f6rnum er \u00far b\u00f3kinni\u00a0<a href=\"https:\/\/archive.org\/details\/bub_gb_y5qVVilqBv8C\">Discours sur les differentes figures des astres<\/a> eftir <a href=\"https:\/\/en.wikipedia.org\/wiki\/Pierre_Louis_Maupertuis\">M. de Maupertuis<\/a> fr\u00e1 1742.<\/span><\/figcaption><\/figure>\n<p>Samkv\u00e6mt athugunum \u00c1rna Hjartarsonar er a\u00f0eins geti\u00f0 um tv\u00e6r halastj\u00f6rnur \u00ed\u00a0 <a href=\"http:\/\/wayback.vefsafn.is\/wayback\/20060522183933\/http:\/\/www.isor.is\/~ah\/comet\/hali16.htm\">\u00edslenskum ann\u00e1lum \u00e1 18. \u00f6ld<\/a>, \u00fea\u00f0 er \u00e1rin 1742 og 1744. \u00cdslendingar h\u00e9r heima vir\u00f0ast jafnvel hafa misst af hinni fr\u00e6gu endurkomu Halley halastj\u00f6rnunnar \u00e1ri\u00f0 1759, hvernig sem \u00e1 \u00fev\u00ed stendur. Hins vegar eru til \u00edslenskar heimildir um halastj\u00f6rnuna miklu 1769 eins og viki\u00f0 ver\u00f0ur a\u00f0 h\u00e9r \u00e1 eftir.<\/p>\n<p>Anna\u00f0 sem vekur athygli, er a\u00f0 <a href=\"http:\/\/uni.hi.is\/einar\/2018\/04\/22\/rasmus-lievog-og-stjornuathuganirnar-i-lambhusum\/\">Rasmus Lievog stj\u00f6rnumeistari<\/a>, sem vann meira e\u00f0a minna samfellt a\u00f0 stj\u00f6rnuathugunum h\u00e9r \u00e1 landi fr\u00e1 haustinu 1779 til loka \u00e1tj\u00e1ndu aldar, nefnir ekki halastj\u00f6rnur \u00ed skj\u00f6lum s\u00ednum. Allavega rakst \u00e9g ekki \u00e1 neinar f\u00e6rslur um halastj\u00f6rnur \u00ed sjarnm\u00e6lingab\u00f3kum hann, \u00feegar \u00e9g renndi n\u00fdlega \u00ed gegnum \u00fe\u00e6r \u00e1 handritadeild \u00dej\u00f3\u00f0arb\u00f3khl\u00f6\u00f0u. \u00de\u00f3 er sk\u00fdrt teki\u00f0 fram \u00ed erindisbr\u00e9fi stj\u00f6rnumeistarans, a\u00f0 eitt af verkefnum hans s\u00e9 a\u00f0 fylgjast me\u00f0 sl\u00edkum fyrirb\u00e6rum og senda uppl\u00fdsingar um \u00feau til Kaupmannahafnar. Sk\u00fdringuna \u00e1 \u00feessari halastj\u00f6rnu\u00feurr\u00f0 \u00feekki \u00e9g ekki.<\/p>\n<hr \/>\n<p><strong>\u25ca Halastjarnan 1742:<\/strong><\/p>\n<p>\u00cd \u00edslenskum ann\u00e1lum m\u00e1 finna tv\u00e6r umsagnir um stj\u00f6rnuna: \u201e<em>\u00deennan vetur s\u00e1st halastjarna b\u00e6\u00f0i h\u00e9r og \u00ed Kh\u00f6fn<\/em>\u201c (<em>Dj\u00e1knaann\u00e1lar<\/em> 1742) og \u201e<em>\u00deann vetr s\u00e1u menn halastj\u00f6rnu, ok \u00e6tlu\u00f0u \u00fe\u00e1 enn flestir at nokkut mundi bo\u00f0a<\/em>\u201c (<em>\u00c1rb\u00e6kur Esp\u00f3l\u00edns<\/em> 1742).<\/p>\n<figure id=\"attachment_6988\" aria-describedby=\"caption-attachment-6988\" style=\"width: 382px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-6988\" src=\"http:\/\/uni.hi.is\/einar\/files\/2018\/08\/c-1742Zurich-copy-300x261.jpg\" alt=\"\" width=\"382\" height=\"332\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/c-1742Zurich-copy-300x261.jpg 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/c-1742Zurich-copy-1024x889.jpg 1024w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/c-1742Zurich-copy-768x667.jpg 768w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/c-1742Zurich-copy.jpg 1200w\" sizes=\"auto, (max-width: 382px) 100vw, 382px\" \/><figcaption id=\"caption-attachment-6988\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">Halastjarnan 1742 yfir Z\u00fcrich \u00ed Sviss.<\/span><\/figcaption><\/figure>\n<p>\u00dearna mun um a\u00f0 r\u00e6\u00f0a halastj\u00f6rnuna C\/1742 C1, sem n\u00fa er einkum \u00feekkt fyrir a\u00f0 hafa vaki\u00f0 s\u00e9rstakan \u00e1huga Eulers. Gl\u00edman vi\u00f0 a\u00f0 \u00e1kvar\u00f0a braut hennar var\u00f0 til \u00feess, a\u00f0 hann \u00fer\u00f3a\u00f0i n\u00fdjar reiknia\u00f0fer\u00f0ir, sem \u00e1 s\u00ed\u00f0ustu \u00e1ratugum \u00e1tj\u00e1ndu aldar l\u00f6g\u00f0u aftur grunninn a\u00f0 einfaldari lei\u00f0um til a\u00f0 finna brautir halastjarna:<\/p>\n<ul>\n<li>L. Euler, 1743:\u00a0 <a href=\"https:\/\/archive.org\/details\/euler-e058\">Determinatio orbitae cometae qui mense Martio huius anni 1742 potissimum fuit observatus.<\/a><\/li>\n<li>L. Euler, 1744: <a href=\"https:\/\/books.google.is\/books?id=WG7ggKrPvCwC&amp;source=gbs_navlinks_s\"> Theoria motuum planetarum et cometarum.<\/a><\/li>\n<\/ul>\n<hr \/>\n<p><strong>\u25ca <a href=\"https:\/\/en.wikipedia.org\/wiki\/Great_Comet_of_1744\">Halastjarnan mikla \u00e1ri\u00f0 1744:<\/a>\u00a0<\/strong><\/p>\n<p>\u00deessarar halastj\u00f6rnu er geti\u00f0 \u00ed nokkrum \u00edslenskum heimildum. Me\u00f0al annars segir \u00ed <span lang=\"IS\"><em>H\u00f6skuldssta\u00f0aann\u00e1l<\/em> 1744: <\/span><\/p>\n<blockquote><p><span lang=\"IS\">\u00deann vetur s\u00e1st jafnan, \u00fe\u00e1 hei\u00f0r\u00edkt var, comete me\u00f0 l\u00f6ngum vendi fr\u00e1 s\u00e9r, er st\u00f3\u00f0 til su\u00f0vesturs, \u00fe\u00e1 s\u00fa stjarna \u00ed n\u00f3nsta\u00f0 var. \u00dea\u00f0 vara\u00f0i fr\u00e1 j\u00f3lum fram til g\u00f3i. \u00ddmisleg himinteikn \u00f6nnur s\u00e1ust \u00fe\u00e1 a\u00f0 m\u00f6rgum \u00feann vetur og \u00e1ri\u00f0 fyrirfarandi, l\u00edka vel fyrri, og munu \u00feau bo\u00f0a\u00f0 hafa eftirkomandi har\u00f0indi til lands og sj\u00f3var og \u00fear af r\u00edsandi f\u00f3lksfelli, fyrst nor\u00f0austur \u00e1 landinu, hvert hall\u00e6ri \u00fear byrja\u00f0i 1741. <\/span><\/p><\/blockquote>\n<p>\u00cd \u00e1\u00f0urnefndri hugvekju sinni um halastj\u00f6rnur minnist Hannes Finnsson \u00e1 stj\u00f6rnuna og segir (bls. 53-54):<\/p>\n<blockquote><p>Halinn \u00e1 \u00feeirri <em>[stj\u00f6rnu]<\/em>, sem s\u00e1st 1744, hver \u00fe\u00f3 var ei n\u00e6rri svo st\u00f3r, sem \u00e1 \u00feeim er \u00e9g fyrr nefndi <em>[1618 og 1680]<\/em>, var m\u00e6ldur a\u00f0 vera 1 millj\u00f3n og 400 \u00fe\u00fasund \u00feingmannalei\u00f0ir.<\/p><\/blockquote>\n<p>\u00de\u00f3tt \u00feess s\u00e9 ekki geti\u00f0 \u00ed \u00edslenskum heimildum, var gl\u00e6silegur hali eitt helsta einkenni \u00feessarar bj\u00f6rtu halastj\u00f6rnu. Halinn klofna\u00f0i \u00feegar stjarnan var \u00ed s\u00f3ln\u00e1nd og mynda\u00f0i um skei\u00f0 einskonar bl\u00e6v\u00e6ng me\u00f0 sex fj\u00f6\u00f0rum.<\/p>\n<figure id=\"attachment_6664\" aria-describedby=\"caption-attachment-6664\" style=\"width: 598px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-6664\" src=\"http:\/\/uni.hi.is\/einar\/files\/2018\/08\/Cheseaux1744-300x217.jpg\" alt=\"\" width=\"598\" height=\"433\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/Cheseaux1744-300x217.jpg 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/Cheseaux1744-1024x739.jpg 1024w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/Cheseaux1744.jpg 1193w\" sizes=\"auto, (max-width: 598px) 100vw, 598px\" \/><figcaption id=\"caption-attachment-6664\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">Franski stj\u00f6rnufr\u00e6\u00f0ingurinn <a href=\"https:\/\/en.wikipedia.org\/wiki\/Jean-Philippe_de_Ch%C3%A9seaux\">J.P. de Cheseaux<\/a> fylgdist vel me\u00f0 halastj\u00f6rnunni 1744. Myndin er \u00far ritsm\u00ed\u00f0 hans um stj\u00f6rnuna og s\u00fdnir vel sexfaldan hala hennar eftir s\u00f3ln\u00e1nd.<\/span><\/figcaption><\/figure>\n<ul>\n<li>J. P. de Cheseaux, 1744:\u00a0 <a href=\"https:\/\/books.google.is\/books?id=BK4UAAAAQAAJ&amp;source=gbs_navlinks_s\">Trait\u00e9 de la comete qui a paru en decembre 1743 &amp; en janvier, fevrier &amp; mars 1744<\/a>.<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h3 style=\"text-align: center\"><span style=\"font-size: 14pt\">Halastjarna Halleys sn\u00fdr aftur<\/span><\/h3>\n<p>Eins og fram kom \u00ed fyrri f\u00e6rslu, sp\u00e1\u00f0i Halley \u00fev\u00ed opinberlega \u00e1ri\u00f0 1705 a\u00f0 halastjarna, sem hann haf\u00f0i fylgst n\u00e1i\u00f0 me\u00f0 1682, myndi birtast \u00e1 n\u00fdjan leik \u00e1ri\u00f0 1758. \u00deegar sp\u00e1in r\u00e6ttist, t\u00f3ku stj\u00f6rnufr\u00e6\u00f0ingar flj\u00f3tlega a\u00f0 tengja nafn Halleys vi\u00f0 stj\u00f6rnuna. \u00cd dag, 260 \u00e1rum s\u00ed\u00f0ar, ber h\u00fan enn nafn hans og er \u00e1n efa fr\u00e6gasta halastjarna allra t\u00edma.<\/p>\n<p>\u00c1 sj\u00f6tta \u00e1ratug \u00e1tj\u00e1ndu aldar var endurkomu stj\u00f6rnunnar be\u00f0i\u00f0 me\u00f0 mikilli eftirv\u00e6ntingu, ekki a\u00f0eins \u00ed Englandi heldur um alla Evr\u00f3pu. \u00c1st\u00e6\u00f0an var fyrst og fremst s\u00fa, a\u00f0 sp\u00e1 Halleys var bygg\u00f0 \u00e1 kenningum Newtons um \u00feyngdina og \u00feeirri tilg\u00e1tu hans \u00ed <a href=\"https:\/\/en.wikipedia.org\/wiki\/Philosophi%C3%A6_Naturalis_Principia_Mathematica\">Princip\u00edum<\/a>, a\u00f0 hreyfing halastjarna v\u00e6ri h\u00e1\u00f0 \u00feyngdarl\u00f6gm\u00e1linu \u00e1 sama h\u00e1tt og hreyfing annarra hnatta \u00ed s\u00f3lkerfinu. Endurkoman var \u00fev\u00ed mikilv\u00e6gur pr\u00f3fsteinn \u00e1 kenningu Newtons um \u00feyngdina. \u00deegar svo halastjarnan birtist nokkurn veginn \u00e1 tilteknum sta\u00f0 og t\u00edma, var henni teki\u00f0 me\u00f0 miklum f\u00f6gnu\u00f0i.<\/p>\n<ul>\n<li>R. Wallis, 1984: <a href=\"https:\/\/www.tandfonline.com\/doi\/abs\/10.1080\/00033798400200271?journalCode=tasc20\">The Glory of Gravity &#8211; Halley&#8217;s Comet 1759.<\/a><\/li>\n<li>C. B. Waff, 1986:\u00a0 <a href=\"http:\/\/adsbit.harvard.edu\/\/full\/1986JHA....17....1W\/0000001.000.html?high=59678436d723218\">Comet Halley&#8217;s First Expected Return: English Public Apprehensions, 1755-58.<\/a><\/li>\n<li>P. Broughton, 1985:\u00a0 <a href=\"http:\/\/adsbit.harvard.edu\/\/full\/1985JHA....16..123B\/0000123.000.html\">The First Predicted Return of Comet Halley.<\/a><\/li>\n<li>C. Wilson, 1993: <a href=\"http:\/\/adsbit.harvard.edu\/\/full\/1993JHA....24....1W\/0000001.000.html\"> Clairaut&#8217;s Calculation of the Eighteenth-Century Return of Halley&#8217;s Comet.<\/a><\/li>\n<li>Wikipedia:\u00a0 <a href=\"https:\/\/en.wikipedia.org\/wiki\/Halley%27s_Comet\">Halley&#8217;s Comet<\/a>.<\/li>\n<li>G. W. Kronk: <a href=\"http:\/\/cometography.com\/pcomets\/001p.html\">1P\/Halley.<\/a><\/li>\n<\/ul>\n<figure id=\"attachment_6601\" aria-describedby=\"caption-attachment-6601\" style=\"width: 514px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-6601\" src=\"http:\/\/uni.hi.is\/einar\/files\/2018\/08\/Halley1759-300x221.jpg\" alt=\"\" width=\"514\" height=\"379\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/Halley1759-300x221.jpg 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/Halley1759-768x567.jpg 768w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/Halley1759.jpg 890w\" sizes=\"auto, (max-width: 514px) 100vw, 514px\" \/><figcaption id=\"caption-attachment-6601\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">Halastjarna Halleys yfir \u00e1nni Thames \u00e1ri\u00f0 1759. M\u00e1lverk eftir Samuel Scott.<\/span><\/figcaption><\/figure>\n<p>Eins og \u00e1\u00f0ur hefur komi\u00f0 fram, vir\u00f0ist Halley-stjarnan ekki hafa s\u00e9st \u00e1 \u00cdslandi \u00e1ri\u00f0 1759. Hennar er \u00fe\u00f3 geti\u00f0 \u00ed hugvekju Hannesar Finnssonar fr\u00e1 1797 (bls. 48-49):<\/p>\n<blockquote><p>Halastj\u00f6rnurnar hafa svo vissan, reglubundinn og afmarka\u00f0ann gang, a\u00f0 l\u00e6r\u00f0ir menn geta reikna\u00f0 n\u00e6r \u00fe\u00e6r komi aftur \u00e1 sama sta\u00f0, og \u00feannig hafa \u00feeir reikna\u00f0 gang h\u00e9rum 80 halastjarna, sem s\u00e9st hafa s\u00ed\u00f0an 837. Halley, mikill stj\u00f6rnuspekingur \u00ed Englandi, reikna\u00f0i \u00fe\u00e6r manna fyrstur fyrir 100 \u00e1rum, og \u00fe\u00e1 \u00feegar 24 af \u00feeim. Hann sag\u00f0i l\u00edka fyrir, a\u00f0 halastjarnan sem s\u00e1st 1682 mundi aftur koma 1759, og muna\u00f0i einum m\u00e1nu\u00f0i \u00ed reikningi hans, hvar til stj\u00f6rnuspekingar hafa s\u00ed\u00f0an sagt ors\u00f6kina, svo a\u00f0 raunar skeika\u00f0i ekki reikningur hans \u00ed hinu allra minnsta.<\/p><\/blockquote>\n<p>Einnig m\u00e1 benda \u00e1 \u00e1g\u00e6ta umfj\u00f6llun um endurkomuna og a\u00f0dragandann a\u00f0 henni \u00ed <a href=\"http:\/\/baekur.is\/bok\/000402495\/0\/127\/Stjornufraedi__lett_og_handa_Bls_127\">Stj\u00f6rnufr\u00e6\u00f0i<\/a> Ursins (bls. 118-121).<\/p>\n<p style=\"text-align: left\"><span style=\"font-size: 12pt\">\u00deess m\u00e1 og geta, a\u00f0 \u00e1ri\u00f0 1758 h\u00e9lt <\/span><a href=\"http:\/\/uni.hi.is\/einar\/2017\/10\/18\/aflfraedi-i-verkum-stefans-bjornssonar\/\">Stef\u00e1n Bj\u00f6rnsson<\/a>, s\u00ed\u00f0ar reiknimeistari, fyrirlestur vi\u00f0 Hafnarh\u00e1sk\u00f3la um halastj\u00f6rnur, sem hann gaf jafnframt \u00fat \u00e1 prenti:<\/p>\n<ul>\n<li>Stef\u00e1n Bj\u00f6rnsson, 1758: <a href=\"https:\/\/notendur.hi.is\/einar\/SAGA\/SB_cometae_1758.pdf\">De effectu cometarum descendentium in systema nostrum planetarium<\/a>.<\/li>\n<\/ul>\n<figure id=\"attachment_1216\" aria-describedby=\"caption-attachment-1216\" style=\"width: 305px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1216 \" src=\"http:\/\/uni.hi.is\/einar\/files\/2017\/10\/halastSB-242x300.jpg\" alt=\"\" width=\"305\" height=\"378\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2017\/10\/halastSB-242x300.jpg 242w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2017\/10\/halastSB.jpg 610w\" sizes=\"auto, (max-width: 305px) 100vw, 305px\" \/><figcaption id=\"caption-attachment-1216\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">Fors\u00ed\u00f0an \u00e1 disp\u00fatat\u00edu Stef\u00e1ns Bj\u00f6rnssonar fr\u00e1 1758. \u00c1 \u00edslensku er titill hennar: <em>Um verkan halastjarna sem ganga ni\u00f0ur \u00ed reikistj\u00f6rnukerfi vort<\/em>.<\/span><\/figcaption><\/figure>\n<p>\u00dea\u00f0 er ekki \u00f3sennilegt, a\u00f0 Stef\u00e1n hafi vali\u00f0 \u00feetta efni vegna umr\u00e6\u00f0unnar um endurkomu Halley-stj\u00f6rnunnar. Umfj\u00f6llunin er \u00f6ll\u00a0bygg\u00f0 \u00e1 n\u00e1tt\u00faruspeki og heimsmynd Newtons og vitnar Stef\u00e1n me\u00f0al annars \u00ed verk hans. Fjalla\u00f0 er \u00edtarlega um \u00feyngdarl\u00f6gm\u00e1li\u00f0 og \u00fev\u00ed l\u00fdst, hvernig halastj\u00f6rnur hreyfast vegna \u00feyngdarhrifa fr\u00e1 s\u00f3linni. Jafnframt r\u00e6\u00f0ir Stef\u00e1n \u00e1hrif halastjarna \u00e1 hreyfingu s\u00f3lar og reikistjarna og einnig um sj\u00e1varf\u00f6ll af \u00feeirra v\u00f6ldum.<\/p>\n<hr \/>\n<p style=\"text-align: left\"><span style=\"font-size: 14pt\"><strong><span style=\"font-size: 12pt\">\u25ca <a href=\"https:\/\/en.wikipedia.org\/wiki\/C\/1769_P1\">Halastjarnan mikla \u00e1ri\u00f0 1769:<\/a> <\/span><\/strong><br \/>\n<\/span><\/p>\n<p>Einn af \u00feeim, sem s\u00e1u \u00feessa halastj\u00f6rnu h\u00e9r \u00e1 landi, var Hannes Finnsson, \u00fe\u00e1 staddur t\u00edmabundi\u00f0 \u00ed Sk\u00e1lholti. \u00cd hugvekju sinni um halastj\u00f6rnur fr\u00e1 1797 segir hann um stj\u00f6rnuna (bls. 54):<\/p>\n<blockquote><p>Halastjarnan, sem s\u00e1st 1769, og sem \u00e9g h\u00e9r \u00ed landi s\u00fdndi nokkrum, s\u00e1st \u00ed 4 m\u00e1nu\u00f0i. Hali hennar reikna\u00f0ist 8 millj\u00f3nir \u00feingmannalei\u00f0ir, en ekki s\u00fdndist hann me\u00f0 beru auga ofsa-langur.<\/p><\/blockquote>\n<p>Eins og fram kemur \u00ed hugvekjunni, haf\u00f0i Hannes ekki miklar \u00e1hyggjur af \u00e1hrifum halastjarna \u00e1 mannl\u00edfi\u00f0, hvorki stj\u00f6rnunnar 1769 n\u00e9 annarra. Hi\u00f0 sama ver\u00f0ur ekki sagt um s\u00edra J\u00f3n Hjaltal\u00edn, eins og sj\u00e1 m\u00e1 \u00ed 23. erindi kv\u00e6\u00f0is hans, <em>Andvara<\/em>, sem fjallar um atbur\u00f0i \u00e1rsins 1770 (s\u00e1lminn \u00ed heild m\u00e1 finna \u00ed vi\u00f0auka vi\u00f0 <a href=\"https:\/\/archive.org\/stream\/AefisagaJonsProfasts\/AEfisaga_Jons_profasts_Bls_7-488#page\/n0\">\u00c6vis\u00f6gu J\u00f3ns pr\u00f3fasts Steingr\u00edmssonar<\/a>):<\/p>\n<blockquote>\n<p style=\"padding-left: 150px\">\u00de\u00e1 t\u00f3k drottinn a\u00f0 h\u00f3ta h\u00f6r\u00f0u,<br \/>\nhalastj\u00f6rnuna s\u00e1um v\u00e9r.<br \/>\nEn \u00feegar skrifa \u00fej\u00f3\u00f0ir gj\u00f6r\u00f0u<br \/>\n\u00fe\u00fasund sj\u00f6 hundru\u00f0 sj\u00f6tiger,<br \/>\nkom h\u00f6rkuvetur kyngi me\u00f0,<br \/>\nkollfeldi b\u00e6\u00f0i hesta og f\u00e9\u00f0.<\/p>\n<\/blockquote>\n<p>\u00cd h\u00f6fu\u00f0borginni Kaupmannah\u00f6fn fylgdust stj\u00f6rnufr\u00e6\u00f0ingarnir \u00ed S\u00edvalaturni, \u00fear \u00e1 me\u00f0al <a href=\"http:\/\/uni.hi.is\/einar\/2017\/11\/22\/eyjolfur-jonsson-fyrsti-islenski-stjornufraedingurinn\/\">Eyj\u00f3lfur J\u00f3nsson<\/a>, vel me\u00f0 stj\u00f6rnunni. \u00deetta m\u00e1 til d\u00e6mis sj\u00e1 \u00e1 nokkrum f\u00e6rslum \u00feeirra \u00ed stjarnm\u00e6lingab\u00e6kur stj\u00f6rnuturnsins.<\/p>\n<figure id=\"attachment_5423\" aria-describedby=\"caption-attachment-5423\" style=\"width: 527px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-5423\" src=\"http:\/\/uni.hi.is\/einar\/files\/2018\/07\/Cometa_1sept1769-300x275.png\" alt=\"\" width=\"527\" height=\"483\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/07\/Cometa_1sept1769-300x275.png 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/07\/Cometa_1sept1769.png 626w\" sizes=\"auto, (max-width: 527px) 100vw, 527px\" \/><figcaption id=\"caption-attachment-5423\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">\u00dar m\u00e6lingab\u00f3kum stj\u00f6rnumeistaranna \u00ed S\u00edvalaturni, 1. september 1769.\u00a0 \u00dearna er veri\u00f0 a\u00f0 \u00e1kva\u00f0a sta\u00f0setningu halastj\u00f6rnukjarnans \u00e1 hvelfingunni. Beina l\u00ednan fr\u00e1 <a href=\"https:\/\/www.stjornufraedi.is\/stjornuskodun\/djupfyrirbaeri\/messierskrain\/messier-45\/\">sj\u00f6stirninu<\/a> (efst til h\u00e6gri) gengur \u00ed gegnum kjarnann og stefnir \u00e1 stj\u00f6rnuna \u03c0 \u00ed <a href=\"https:\/\/www.stjornufraedi.is\/stjornuskodun\/stjornumerkin\/orion\/\">\u00d3r\u00edon<\/a>. Hornpunkrarnir \u00ed sams\u00ed\u00f0ungnum eru allir \u00ed <a href=\"https:\/\/www.stjornufraedi.is\/stjornuskodun\/stjornumerkin\/nautid\/\">Nautsmerki<\/a>: Fastastj\u00f6rnurnar\u00a0\u03b1 (<a href=\"https:\/\/en.wikipedia.org\/wiki\/Aldebaran\">Aldebaran<\/a>),\u00a0 \u03bb,\u00a0 \u03bd og kjarni halastj\u00f6rnunnar. &#8211; \u00dar <a href=\"http:\/\/css.au.dk\/fileadmin\/reposs\/reposs-041.pdf\">meistararitger\u00f0<\/a> C. S. J\u00f6rgensen fr\u00e1 2017 (bls. 231).<\/span><\/figcaption><\/figure>\n<p>Pr\u00f3fessor Christian Horrebow vir\u00f0ist ekki hafa hirt um a\u00f0 birta ni\u00f0urst\u00f6\u00f0ur \u00feessara d\u00f6nsku m\u00e6linga, Starfsb\u00f3\u00f0ir hans \u00ed Stokkh\u00f3lmi, <a href=\"https:\/\/sv.wikipedia.org\/wiki\/Pehr_Wargentin\">Pehr Wargentin<\/a>, l\u00e1 hins vegar ekki \u00e1 s\u00ednum ni\u00f0urst\u00f6\u00f0um. \u00cd grein hans um halastj\u00f6rnuna m\u00e1 me\u00f0al annars finna \u00e1g\u00e6tis kort af hreyfingu hennar \u00e1 hvelfingunni.<\/p>\n<ul>\n<li>P. Wragentin, 1770:\u00a0 <a href=\"https:\/\/archive.org\/stream\/swenskawetensk1311770horr#page\/n199\">Observationer p\u00e5 1769 \u00e5rs Comet, gjorda i Stockholm<\/a>.<\/li>\n<\/ul>\n<figure id=\"attachment_6641\" aria-describedby=\"caption-attachment-6641\" style=\"width: 609px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-6641\" src=\"http:\/\/uni.hi.is\/einar\/files\/2018\/08\/wargentin_full-1769-300x131.jpeg\" alt=\"\" width=\"609\" height=\"266\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/wargentin_full-1769-300x131.jpeg 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/wargentin_full-1769-1024x449.jpeg 1024w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/wargentin_full-1769-768x337.jpeg 768w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/wargentin_full-1769-1536x673.jpeg 1536w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/wargentin_full-1769-2048x897.jpeg 2048w\" sizes=\"auto, (max-width: 609px) 100vw, 609px\" \/><figcaption id=\"caption-attachment-6641\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">Teikning P. Wargentins af sl\u00f3\u00f0 halastj\u00f6rnunnar 1769 dagana 3. til 12. september.<\/span><\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<h3 style=\"text-align: center\"><span style=\"font-size: 14pt\">Leit a\u00f0 n\u00fdjum halastj\u00f6rnum<br \/>\n<\/span><\/h3>\n<p>Sk\u00f6mmu eftir mi\u00f0ja \u00e1tj\u00e1ndu \u00f6ld t\u00f3k a\u00f0 bera \u00e1 samkeppni milli stj\u00f6rnufr\u00e6\u00f0inga \u00ed Frakklandi um \u00fea\u00f0, hver yr\u00f0i fyrstur til a\u00f0 finna n\u00fdjar halastj\u00f6rnur. Lengi var <a href=\"https:\/\/en.wikipedia.org\/wiki\/Charles_Messier\">C. Messier<\/a> \u00fear \u00ed \u00f3tv\u00edr\u00e6\u00f0u forusthlutverki, en s\u00ed\u00f0ar f\u00e9kk hann har\u00f0a samkeppni fr\u00e1 <a href=\"https:\/\/en.wikipedia.org\/wiki\/Pierre_M%C3%A9chain\">P. M\u00e9chain<\/a>. \u00cd byrjun n\u00edtj\u00e1ndu aldar sl\u00f3st <a href=\"https:\/\/en.wikipedia.org\/wiki\/Jean-Louis_Pons\">J.-L. Pons<\/a> svo \u00ed h\u00f3pinn og \u00e1\u00f0ur en yfir lauk haf\u00f0i honum tekist a\u00f0 finna fleiri halastj\u00f6rnur en nokkur annar.<\/p>\n<p>Margir a\u00f0rir, b\u00e6\u00f0i \u00ed Frakklandi og annars sta\u00f0ar, bl\u00f6ndu\u00f0u s\u00e9r \u00ed bar\u00e1ttuna og \u00feegar lei\u00f0 \u00e1 n\u00edtj\u00e1ndu \u00f6ldina, t\u00f3ku Bandar\u00edkjamenn sm\u00e1m saman forustuna. \u00deeirra duglegastur var \u00e1n efa <a href=\"https:\/\/en.wikipedia.org\/wiki\/William_Robert_Brooks\">W. R. Brooks<\/a>.<\/p>\n<p>Af \u00f6llum \u00feessum m\u00f6nnum er Messier lang \u00feekktastur. \u00dea\u00f0 er \u00fe\u00f3 ekki vegna halastjarnanna, sem hann fann, heldur fyrir <a href=\"https:\/\/en.wikipedia.org\/wiki\/Messier_object\">lista yfir \u00feokukennda hno\u00f0ra \u00e1 himni<\/a>, sem ekki eru halastj\u00f6rnur. Listann setti hann saman, til \u00feess a\u00f0 hno\u00f0rarnir tef\u00f0u hann ekki vi\u00f0 halastj\u00f6rnuleitina, en a\u00f0 \u00f6\u00f0ru leyti haf\u00f0i hann l\u00edtinn \u00e1huga \u00e1 \u00feessum hreyfingarlausu fyrirb\u00e6rum. \u00dea\u00f0 flokkast \u00fev\u00ed kannski undir kaldh\u00e6\u00f0ni \u00f6rlaganna, a\u00f0 <a href=\"https:\/\/www.nasa.gov\/content\/goddard\/hubble-s-messier-catalog\">Messier-listinn<\/a> er n\u00fana ein \u00feekktasta gagnaskr\u00e1 stj\u00f6rnufr\u00e6\u00f0innar.<\/p>\n<p>L\u00edkt og \u00e1 \u00f6\u00f0rum fr\u00e6\u00f0asvi\u00f0um voru karlar \u00ed yfirgn\u00e6fandi meirihluta \u00ed l\u00e6rd\u00f3msheimi stj\u00f6rnufr\u00e6\u00f0innar \u00e1 sautj\u00e1ndu og \u00e1tj\u00e1ndu \u00f6ld. \u00dev\u00ed er \u00e1st\u00e6\u00f0a til a\u00f0 nefna s\u00e9rstaklega \u00ferj\u00e1r konur, sem stundu\u00f0u almennar ranns\u00f3knir \u00ed stj\u00f6rnufr\u00e6\u00f0i \u00e1 \u00feessu t\u00edmabili, \u00fear \u00e1 me\u00f0al \u00e1 halastj\u00f6rnum. \u00de\u00e6r eru <a href=\"https:\/\/en.wikipedia.org\/wiki\/Maria_Margaretha_Kirch\">Maria Margaretha Kirch<\/a>, fyrsta konan sem vita\u00f0 er til a\u00f0 fundi\u00f0 hafi n\u00fdja halastj\u00f6rnu (C\/1702 H1), <a href=\"https:\/\/en.wikipedia.org\/wiki\/Caroline_Herschel\">Caroline Lucretia Herschel<\/a>, sem fann a\u00f0 minnsta kosti fimm sl\u00edkar og loks <a href=\"https:\/\/en.wikipedia.org\/wiki\/Maria_Mitchell\">Maria Mitchell<\/a>, sem fyrst s\u00e1 n\u00fdja halastj\u00f6rnu \u00e1ri\u00f0 1847. S\u00fa sjarna er oft <a href=\"https:\/\/en.wikipedia.org\/wiki\/C\/1847_T1\">vi\u00f0 hana kennd<\/a>.<\/p>\n<p>A\u00f0 lokum m\u00e1 nefna, a\u00f0 enginn \u00cdslendingur mun enn hafa veri\u00f0 svo heppinn a\u00f0 finna n\u00fdja halastj\u00f6rnu. Til mikils er a\u00f0 vinna, \u00fev\u00ed yfirleitt er halastj\u00f6rnunni gefi\u00f0 nafn finnandans auk skr\u00e1rarn\u00famers.<\/p>\n<ul>\n<li>Wikipedia: <a href=\"https:\/\/en.wikipedia.org\/wiki\/Category:Discoverers_of_comets\">Discoverers of comets.<\/a><\/li>\n<li>Wikipedis: <a href=\"https:\/\/en.wikipedia.org\/wiki\/Naming_of_comets\">Naming of comets.<\/a><\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h3 style=\"text-align: center\"><span style=\"font-size: 14pt\">N\u00edtj\u00e1nda \u00f6ldin<\/span><\/h3>\n<p>Langt fram eftir n\u00edtj\u00e1ndu \u00f6ld l\u00f6g\u00f0u stj\u00f6rnufr\u00e6\u00f0ingar megin\u00e1herslu \u00e1 \u00fea\u00f0 a\u00f0 n\u00fdta sem best st\u00e6r\u00f0fr\u00e6\u00f0ilegu a\u00f0fer\u00f0irnar, sem \u00feeir h\u00f6f\u00f0u fengi\u00f0 \u00ed arf eftir \u00fe\u00e1 Euler, Lambert, Lagrange, Laplace, Olbers og Gauss. Brautir himinhnatta, \u00fear \u00e1 me\u00f0al halastjarna, voru \u00e1kvar\u00f0a\u00f0ar me\u00f0 \u00e6 meiri n\u00e1kv\u00e6mni. Jafnframt var mikil vinna l\u00f6g\u00f0 \u00ed \u00fer\u00f3un og sm\u00ed\u00f0i n\u00fdrra sj\u00f3nauka, ekki s\u00edst linsusj\u00f3nauka, einkum til \u00feess a\u00f0 geta framkv\u00e6mt sem n\u00e1kv\u00e6mastar sta\u00f0ar- og t\u00edmam\u00e6lingar.<\/p>\n<p>Upp \u00far mi\u00f0ri \u00f6ldinn var \u00ed s\u00edvaxandi m\u00e6li fari\u00f0 a\u00f0 beita n\u00fdjungum \u00ed e\u00f0lisfr\u00e6\u00f0i og efnafr\u00e6\u00f0i, einkum litr\u00f3fsgreiningu og lj\u00f3smyndat\u00e6kni, til a\u00f0 afla n\u00fdrrar \u00feekkingar \u00e1 e\u00f0liseiginleikum og heg\u00f0un himinhnatta. \u00deetta olli sannkalla\u00f0ri byltingu \u00ed ranns\u00f3knum \u00e1 s\u00f3linni og \u00f6\u00f0rum s\u00f3lstj\u00f6rnum, reikistj\u00f6rnum og tunglum \u00feeirra sem og halastj\u00f6rnum og sm\u00e1stirnum.<\/p>\n<p>Eftirtaldar heimildir gefa, sem heild, allg\u00f3\u00f0a mynd af \u00fer\u00f3un stjarnv\u00edsinda \u00e1 n\u00edtj\u00e1ndu \u00f6ld:<\/p>\n<ul>\n<li>Einar H. Gu\u00f0mundsson, 2018: <a href=\"http:\/\/uni.hi.is\/einar\/2018\/06\/24\/halastjarnan-mikla-arid-1858-maelingar-og-hughrif-i-upphafi-nyrra-tima-i-stjornufraedi\/\">Halastjarnan mikla \u00e1ri\u00f0 1858 &#8211; M\u00e6lingar og hughrif \u00ed upphafi n\u00fdrra t\u00edma \u00ed stj\u00f6rnufr\u00e6\u00f0i<\/a>.<\/li>\n<li>A. W. Hirsfeld, 2004: <a href=\"http:\/\/search.ebscohost.com\/login.aspx?direct=true&amp;db=f5h&amp;AN=12437465&amp;site=ehost-live\">Picturing the Heavens<\/a>.<\/li>\n<li>A. W. Hirsfeld, 2004: <a href=\"http:\/\/search.ebscohost.com\/login.aspx?direct=true&amp;db=f5h&amp;AN=13722842&amp;site=ehost-live\">Starlight Detectives.<\/a><\/li>\n<li>J.\u00a0Hearnshaw, 2010: <a href=\"http:\/\/adsabs.harvard.edu\/full\/2010JAHH...13...90H\">Auguste Comte&#8217;s blunder: an account of the first century of stellar spectroscopy and how it took one hundred years to prove that Comte was wrong!<\/a>.<\/li>\n<li>A. Guillermin, 1875: <a href=\"https:\/\/books.google.is\/books?id=6cNrAAAAIAAJ&amp;source=gbs_navlinks_s\">The World of Comets.<\/a><\/li>\n<li>S. P. Langley, 1888: <a href=\"https:\/\/archive.org\/details\/newastronomy00langrich\">The New Astronomy.<\/a><\/li>\n<li>A. M. Clerke, 1902: <a href=\"https:\/\/archive.org\/details\/apopularhistory00clergoog\">A Popular History of Astronomy during the Nineteenth Century.<\/a><\/li>\n<\/ul>\n<hr \/>\n<p><strong>\u25ca <a href=\"https:\/\/en.wikipedia.org\/wiki\/C\/1807_R1\">Halastjarnan mikla \u00e1ri\u00f0 1807:<\/a><\/strong><\/p>\n<p>\u00c9g hef a\u00f0eins fundi\u00f0 eina heimild um \u00fea\u00f0, a\u00f0 \u00feessi halastjarna hafi s\u00e9st h\u00e9r \u00e1 landi. Thomas Bugge getur \u00feess \u00ed lok greinar um ranns\u00f3knir s\u00ednar \u00e1 stj\u00f6rnunni, a\u00f0 landm\u00e6lingamennirnir Frisak og <a href=\"https:\/\/no.wikipedia.org\/wiki\/Hans_Jacob_von_Scheel_(1779%E2%80%931851)\">Scheel<\/a> hafi s\u00e9\u00f0 hana fr\u00e1 Eyjafir\u00f0i. \u00der\u00e1tt fyrir a\u00f0 \u00feeir hafi veri\u00f0 n\u00fdkomnir \u00feanga\u00f0 og m\u00e6lit\u00e6ki \u00feeirra enn \u00e1 lei\u00f0inni, t\u00f3kst \u00feeim a\u00f0 gera nokkrar m\u00e6lingar \u00e1 stj\u00f6rnunni me\u00f0 einf\u00f6ldum a\u00f0fer\u00f0um og senda Bugge. Pr\u00f3fessorinn birti \u00fe\u00e6r svo \u00ed greininni (bls. 221-22).<\/p>\n<figure id=\"attachment_7149\" aria-describedby=\"caption-attachment-7149\" style=\"width: 537px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-7149\" src=\"http:\/\/uni.hi.is\/einar\/files\/2018\/08\/Bugge1807-300x243.png\" alt=\"\" width=\"537\" height=\"435\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/Bugge1807-300x243.png 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/Bugge1807.png 575w\" sizes=\"auto, (max-width: 537px) 100vw, 537px\" \/><figcaption id=\"caption-attachment-7149\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">\u00dar grein Bugges um halastj\u00f6rnuna 1807 (bls. 271). \u00cd ne\u00f0ra horninu vinstra megin m\u00e1 sj\u00e1 teikningar af stj\u00f6rnunni \u00e1 \u00feremur mismunandi t\u00edmum.\u00a0 Hinar myndirnar tengjast \u00fdmsum \u00fatreikningum, sem finna m\u00e1 \u00ed greininni.<br \/><\/span><\/figcaption><\/figure>\n<ul>\n<li>Th. Bugge, 1810: <a href=\"https:\/\/www.biodiversitylibrary.org\/item\/182420#page\/153\/mode\/1up\">Betragtninger over Cometer i Almindelighed og Observationer paa Cometen i October, November og December 1807.<\/a><\/li>\n<li>Arnar B. \u00d3lafsson, 2014: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=6166028\">Af merkilegu korti.<\/a><\/li>\n<\/ul>\n<hr \/>\n<p><strong>\u25ca <a href=\"https:\/\/en.wikipedia.org\/wiki\/Great_Comet_of_1811\">Halastjarnan mikla \u00e1ri\u00f0 1811:<\/a><\/strong><\/p>\n<p>\u00cd \u00c1rb\u00f3kum Esp\u00f3l\u00edns segir um \u00feessa \u00feekktu stj\u00f6rnu: \u201e<em>Haust var gott fyrir nor\u00f0an; s\u00e1st \u00fe\u00e1 halastjarna, ok svo \u00f6ndver\u00f0an vetrinn<\/em>.\u201c<\/p>\n<p>\u00cd fr\u00e9tt \u00ed <em>Fj\u00f6lni<\/em> um komu halastj\u00f6rnu Halleys \u00e1ri\u00f0 1835 (sj\u00e1 s\u00ed\u00f0ar) segir \u00ed lokin:<\/p>\n<blockquote><p>Pr\u00f3fessor Ursin gerir ekki r\u00e1\u00f0 fyrir a\u00f0 <em>[Halley-stjarnan]<\/em> ver\u00f0i mj\u00f6g f\u00f6gur \u00ed \u00feetta sinn e\u00f0a geti jafnast vi\u00f0 \u00fe\u00e1 sem s\u00e1st 1811; enda var s\u00fa stjarna vo\u00f0aleg, og mun vera \u00f6llum \u00ed minni, sem muna til s\u00edn \u00fe\u00e1.<\/p><\/blockquote>\n<p>\u00c1ri\u00f0 1839 minnist J\u00f3n Bjarnason \u00ed \u00de\u00f3rormstungu einnig \u00e1 stj\u00f6rnuna \u00ed br\u00e9fi til Bj\u00f6rns Gunnlaugssonar (sj\u00e1 n\u00e1nar s\u00ed\u00f0ar) og segir: \u201e<em>M\u00e9r er minnisst\u00e6\u00f0 Cometan af 1811 vegna hennar st\u00e6r\u00f0ar.<\/em>\u201c<\/p>\n<ul>\n<li>G. W. Kronk: <a href=\"http:\/\/cometography.com\/lcomets\/1811f1.html\">C\/1811 F1 (Great Comet).<\/a><\/li>\n<\/ul>\n<p>Sj\u00e1 einnig <em>Vi\u00f0b\u00f3t 1<\/em> aftast \u00ed f\u00e6rslunni.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-6592 aligncenter\" src=\"http:\/\/uni.hi.is\/einar\/files\/2018\/08\/C0metCA1830-300x217.jpg\" alt=\"\" width=\"437\" height=\"316\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/C0metCA1830-300x217.jpg 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/C0metCA1830-1024x739.jpg 1024w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/C0metCA1830-768x554.jpg 768w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/C0metCA1830.jpg 1200w\" sizes=\"auto, (max-width: 437px) 100vw, 437px\" \/><\/p>\n<p><strong>\u25ca Halastjarnan 1818:<\/strong><\/p>\n<p>\u00cd \u00e1\u00f0urnefndu br\u00e9fi s\u00ednu til Bj\u00f6rns Gunnlaugssonar minnist J\u00f3n Bjarnason \u00e1 stj\u00f6rnuna me\u00f0 \u00feessum or\u00f0um: \u201e<em>M\u00e9r er minnisst\u00e6\u00f0 <\/em>[&#8230;]<em> halastjarnan 1818 (sem \u00fe\u00f3 f\u00e1ir munu hafa s\u00e9\u00f0) vegna hennar langa og mj\u00f3a hala<\/em>.\u201c<\/p>\n<p>\u00dearna var v\u00e6ntanlega \u00e1 fer\u00f0inni ein af fj\u00f3rum halastj\u00f6rnum, sem Pons fann \u00feetta \u00e1ri\u00f0. Hin stutta l\u00fdsing\u00a0 J\u00f3ns bendir og eindregi\u00f0 til \u00feess, a\u00f0 \u00fearna s\u00e9 um a\u00f0 r\u00e6\u00f0a hina fr\u00e6gu halastj\u00f6rnu Enckes.<\/p>\n<ul>\n<li>Wikipedia:\u00a0<a href=\"https:\/\/en.wikipedia.org\/wiki\/Comet_Encke\">Encke&#8217;s comet.<\/a><\/li>\n<li>G. W. Kronk: <a href=\"http:\/\/cometography.com\/pcomets\/002p.html\">2P\/Encke.<\/a><\/li>\n<li>G. F. Ursin, 1842: <a href=\"http:\/\/baekur.is\/bok\/000402495\/0\/127\/Stjornufraedi__lett_og_handa_Bls_127\">Stj\u00f6rnufr\u00e6\u00f0i<\/a> (bls. 121-123).<\/li>\n<\/ul>\n<hr \/>\n<p><strong>\u25ca <a href=\"https:\/\/en.wikipedia.org\/wiki\/Great_Comet_of_1823\">Halastjarnan mikla \u00e1ri\u00f0 1823:<\/a><\/strong><\/p>\n<p>Magn\u00fas Stephensen fjallar um \u00feessa stj\u00f6rnu \u00ed erlendum fr\u00e9ttum \u00ed <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=1057624\">Klausturp\u00f3stinum<\/a> \u00ed september 1824 og segir hana hafa s\u00e9st \u00ed Berl\u00edn og Danm\u00f6rku \u00ed jan\u00faar \u00fea\u00f0 \u00e1r. Svo b\u00e6tir hann vi\u00f0: \u201e<em>\u00c1 \u00cdslandi s\u00e1st h\u00fan og \u00e1 \u00feorranum<\/em>.\u201c<\/p>\n<hr \/>\n<p><strong>\u25ca Halastjarnan 1826:<\/strong><\/p>\n<p><span id=\"messageContent\">\u00deetta er halastjarna, sem Bj\u00f6rn Gunnlaugsson fylgdist me\u00f0 fr\u00e1 \u00c1lftanesi \u00ed byrjun desember 1826 og skrifa\u00f0i um \u00ed <em>Klausturp\u00f3stinn<\/em>. N\u00fdleg k\u00f6nnun m\u00edn hefur leitt \u00ed lj\u00f3s, a\u00f0 \u00fearna var \u00e1 fer\u00f0inni <\/span>halastjarna, sem \u00e1\u00f0urnefndur Pons s\u00e1 fyrstur manna\u00a0 22. okt\u00f3ber 1826. Skr\u00e1rheiti hennar er n\u00fa <span id=\"messageContent\"><em>C\/1826 U1 (Pons)<\/em> en var \u00e1\u00f0ur <em>Comet 1826 V<\/em>.\u00a0 Stjarnan var \u00ed <\/span><span id=\"messageContent\">s\u00f3ln\u00e1nd 18. n\u00f3vember 1826 og <\/span><span id=\"messageContent\">Bj\u00f6rn s\u00e1 hana \u00fev\u00ed \u00e1 \u00fatlei\u00f0. \u00cd reikningum s\u00ednum ger\u00f0i hann hins vegar r\u00e1\u00f0 fyrir, a\u00f0 h\u00fan v\u00e6ri \u00e1 innlei\u00f0 og l\u00edklega er \u00fea\u00f0 sk\u00fdringin \u00e1 \u00fev\u00ed, hvers vegna ni\u00f0urst\u00f6\u00f0ur hans eru rangar.<br \/>\n<\/span><\/p>\n<ul>\n<li>Bj\u00f6rn Gunnlaugsson, 1826: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=1057992\">Halastjarnan 1826.<\/a><\/li>\n<li><span id=\"messageContent\">A. Hnatek, 1908: <a href=\"http:\/\/adsbit.harvard.edu\/\/full\/1908AN....178..337H\/0000176.000.html\">Nachtrag zur definitiven Bahnbestimmung des Kometen 1826 V.<\/a><br \/>\n<\/span><\/li>\n<\/ul>\n<hr \/>\n<p><strong>\u25ca <a href=\"https:\/\/en.wikipedia.org\/wiki\/Biela%27s_Comet\">Biela halastjarnan 1832:<\/a><\/strong><\/p>\n<p>\u00c1ri\u00f0 1832 kom upp or\u00f0r\u00f3mur \u00feess efnis a\u00f0 Biela-stjarnan, sem var v\u00e6ntanleg seinna \u00fea\u00f0 \u00e1r, myndi rekast \u00e1 j\u00f6r\u00f0ina. Af \u00feessu skapa\u00f0ist nokkur \u00f3tti, ekki s\u00edst \u00ed Par\u00eds. Til a\u00f0 r\u00f3a samlanda s\u00edna greip <a href=\"https:\/\/en.wikipedia.org\/wiki\/Fran%C3%A7ois_Arago\">F. Arago<\/a> pennann og skrifa\u00f0i langan b\u00e6kling um halastj\u00f6rnur og hverfandi \u00e1hrif \u00feeirra \u00e1 j\u00f6r\u00f0ina. \u00d3ttinn vi\u00f0 stj\u00f6rnuna hefur \u00fe\u00f3 greinilega borist til \u00cdslands, \u00fev\u00ed \u00ed \u00fe\u00fd\u00f0ingu sinni \u00e1 <em>Stj\u00f6rnufr\u00e6\u00f0i<\/em> Ursins breytti J\u00f3nas Hallgr\u00edmsson fr\u00e1 upphaflegum texta h\u00f6fundarins um atbur\u00f0inn og segir me\u00f0al annars (bls. 132):<\/p>\n<blockquote><p>Stj\u00f6rnufr\u00e6\u00f0ingarnir s\u00f6g\u00f0u til a\u00f0 mynda, a\u00f0 halastjarna Bielas mundi koma svo n\u00e6rri <em>jar\u00f0brautinn<\/em>i \u00ed okt\u00f3berm\u00e1nu\u00f0i 1832, a\u00f0 h\u00fan yr\u00f0i 13 sinnum n\u00e6r henni en tungli\u00f0 er j\u00f6r\u00f0inni og \u00fea\u00f0 geti bori\u00f0 oftar vi\u00f0; en hitt s\u00f6g\u00f0u \u00feeir ekki, a\u00f0 h\u00fan yr\u00f0i \u00fe\u00e1 svo n\u00e6rri <em>j\u00f6r\u00f0unni sj\u00e1lfri<\/em>; \u00fev\u00ed j\u00f6r\u00f0in var \u00fe\u00e1 langt \u00e1 eftir og kom ekki \u00e1 \u00feann sta\u00f0 \u00e1 braut sinni, er halastjarnan haf\u00f0i fari\u00f0 framhj\u00e1, fyrr en m\u00e1nu\u00f0i seinna, og \u00fe\u00e1 var hin komin \u00fea\u00f0an langar lei\u00f0ir. Samt var \u00feetta svo misskili\u00f0, hva\u00f0 sem vitrari menn s\u00f6g\u00f0u, a\u00f0 almenningur \u00e6r\u00f0ist a\u00f0 kalla m\u00e1tti v\u00ed\u00f0a um l\u00f6nd og J\u00fap\u00edter sj\u00e1lfur, er \u00fe\u00e1 var n\u00e1l\u00e6gt\u00a0 jar\u00f0stefnu sinni og fagur og bjartur \u00e1 a\u00f0 sj\u00e1, var lengi um sumari\u00f0 kalla\u00f0ur \u201ehalastjarna\u201c og \u201elo\u00f0inn fjandi\u201c, s\u00f6g\u00f0u \u00feeir h\u00e9rna \u00ed Reykjav\u00edk.<\/p><\/blockquote>\n<figure id=\"attachment_7204\" aria-describedby=\"caption-attachment-7204\" style=\"width: 596px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-7204 \" src=\"http:\/\/uni.hi.is\/einar\/files\/2018\/08\/CometBiela1846-300x141.jpg\" alt=\"\" width=\"596\" height=\"280\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/CometBiela1846-300x141.jpg 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/CometBiela1846-768x362.jpg 768w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/CometBiela1846.jpg 800w\" sizes=\"auto, (max-width: 596px) 100vw, 596px\" \/><figcaption id=\"caption-attachment-7204\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">Teikning af Biela-halastj\u00f6rnunni fr\u00e1 \u00e1rinu 1846, sk\u00f6mmu eftir a\u00f0 h\u00fan klofna\u00f0i \u00ed tvennt.<\/span><\/figcaption><\/figure>\n<ul>\n<li>F. Arago, 1832: <a href=\"https:\/\/books.google.is\/books?id=tkEBAAAAYAAJ&amp;source=gbs_navlinks_s\"> Tract on Comets: And Particularly on the Comet that is to Intersect the Earth&#8217;s Path in October, 1832.<\/a><\/li>\n<li>G. W. Kronk: <a href=\"http:\/\/cometography.com\/pcomets\/003d.html\">3D\/Biela.<\/a><\/li>\n<\/ul>\n<hr \/>\n<p><strong>\u25ca <a href=\"https:\/\/en.wikipedia.org\/wiki\/Halley%27s_Comet\">Halley halastjarnan 1835:<\/a><\/strong><\/p>\n<p>\u00cd fr\u00e9tt \u00ed t\u00edmaritinu <em>Fj\u00f6lni<\/em> um endurkomu Halley-stj\u00f6rnunnar \u00e1ri\u00f0 1835 er a\u00f0 finna eftirfarandi sp\u00e1:<\/p>\n<blockquote><p><span lang=\"IS\">Snemma \u00ed \u00e1g\u00fast \u00e1 h\u00fan a\u00f0 vera \u00ed nauts-merkinu, n\u00e1l\u00e6gt sj\u00f6stj\u00f6rnunum. \u00dea\u00f0an f\u00e6rist h\u00fan nor\u00f0ur \u00e1 vi\u00f0 og s\u00fdnist fara hra\u00f0ast fyrst \u00ed okt\u00f3ber. \u00deann 5ta, 6ta og 7da \u00ed \u00feeim m\u00e1nu\u00f0i fer h\u00fan yfir vagninn og \u00feann 11ta \u00e1 h\u00fan a\u00f0 ver\u00f0a \u00ed kr\u00f3nunni r\u00e9tt hj\u00e1 bj\u00f6rtu-stj\u00f6rnu (gemma coron\u00e6); \u00de\u00e1 er h\u00fan \u00e1 \u00cdslandi a\u00f0 sj\u00e1 \u00ed nor\u00f0vestri seint \u00e1 kv\u00f6ldin. Eftir mi\u00f0jan m\u00e1nu\u00f0inn fer h\u00fan su\u00f0ur yfir l\u00ednuna, stendur kyrr nokkru seinna og kemur \u00ed s\u00f3larn\u00e1nd 7da n\u00f3vember;<em> [\u2026]\u00a0<\/em> \u00dar \u00feessu fer h\u00fan a\u00f0 \u00feokast austur\u00e1vi\u00f0, en ver\u00f0ur \u00fe\u00e1 svo l\u00e1gt \u00e1 su\u00f0urloftinu, a\u00f0 h\u00fan er horfin \u00e1 \u00cdslandi um j\u00f3laleyti\u00f0.<br \/>\n<\/span><\/p><\/blockquote>\n<p>\u00dev\u00ed mi\u00f0ur hef \u00e9g ekki fundi\u00f0 neinar heimildir um \u00fea\u00f0, a\u00f0 gesturinn hafi s\u00e9st h\u00e9r \u00e1 landi.<\/p>\n<figure id=\"attachment_6593\" aria-describedby=\"caption-attachment-6593\" style=\"width: 538px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-6593\" src=\"http:\/\/uni.hi.is\/einar\/files\/2018\/08\/Cork_Halley1835-300x197.jpg\" alt=\"\" width=\"538\" height=\"353\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/Cork_Halley1835-300x197.jpg 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/Cork_Halley1835.jpg 500w\" sizes=\"auto, (max-width: 538px) 100vw, 538px\" \/><figcaption id=\"caption-attachment-6593\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">Halastjarna Halleys yfir b\u00e6num Cork \u00e1 \u00cdrlandi \u00e1ri\u00f0 1835.<\/span><\/figcaption><\/figure>\n<ul>\n<li>Ritst\u00f3rn <em>Fj\u00f6lnis<\/em> (J\u00f3nas Hallgr\u00edmsson?), 1835: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=2012248\">Halastjarna.<\/a><\/li>\n<li>G. W. Kronk: <a href=\"http:\/\/cometography.com\/pcomets\/001p.html\">1P\/Halley.<\/a><\/li>\n<\/ul>\n<hr \/>\n<p><strong>\u25ca Halastjarnan 1838:<\/strong><\/p>\n<p>\u00c1 handritadeildinni \u00ed \u00dej\u00f3\u00f0arb\u00f3khl\u00f6\u00f0u er var\u00f0veitt sendibr\u00e9f, sem\u00a0 <a href=\"https:\/\/is.wikipedia.org\/wiki\/J%C3%B3n_Bjarnason_(b%C3%B3ndi)\">J\u00f3n Bjarnason b\u00f3ndi \u00ed \u00de\u00f3rormstungu<\/a> skrifa\u00f0i Birni Gunnlaugssyni 12. febr\u00faar \u00e1ri\u00f0 1839 (<em>Lbs. 386, fol<\/em>). A\u00f0alefni br\u00e9fsins er umfj\u00f6llun um halastj\u00f6rnu, sem J\u00f3n s\u00e1 hausti\u00f0 1838 og hefur sennilega veri\u00f0\u00a0 Encke-stjarnan, s\u00fa hin sama og J\u00f3n haf\u00f0i \u00e1\u00f0ur s\u00e9\u00f0 1818.\u00a0 L\u00fdsing J\u00f3ns hlj\u00f3\u00f0ar svo:<\/p>\n<blockquote><p>M\u00e9r er minnisst\u00e6\u00f0 Cometan af 1811 vegna hennar st\u00e6r\u00f0ar og l\u00edka halastjarnan 1818 (sem \u00fe\u00f3 f\u00e1ir munu hafa s\u00e9\u00f0) vegna hennar langa og mj\u00f3a hala. <em>[&#8230;]<\/em> Kjarni e\u00f0ur h\u00f6fu\u00f0 Cometunnar af 1811 vir\u00f0ist ei st\u00e6rra heldur en \u00feeirrar sem s\u00fdndi sig \u00e1 n\u00e6st li\u00f0nu hausti. S\u00fa (af 1811) f\u00e6r\u00f0ist daglega minna til su\u00f0urs eptir himni heldur en s\u00fa \u00ed haust e\u00f0 var og \u00fev\u00ed hygg eg s\u00fa hafi ekki eins n\u00e6rri komi\u00f0 <em>\u2295<\/em> og \u00fear hj\u00e1 s\u00e1st s\u00fa miklu lengur.<\/p><\/blockquote>\n<p>\u00dea\u00f0 sem er samt \u00e1hugaver\u00f0ast vi\u00f0 \u00feetta br\u00e9f er l\u00fdsing \u00e1 \u00fatreikningum, sem J\u00f3n er a\u00f0 gl\u00edma vi\u00f0. \u00c1\u00f0ur hefur Bj\u00f6rn greinilega sent honum\u00a0 lei\u00f0beiningar um \u00fea\u00f0, hvernig finna skuli brautir halastjarna, b\u00e6\u00f0i reiknia\u00f0fer\u00f0ir og form\u00falur. Auk \u00feess hefur Bj\u00f6rn sent honum d\u00e6mi og \u00ed br\u00e9fi J\u00f3ns eru lausnir, sem hann bi\u00f0ur Bj\u00f6rn a\u00f0 l\u00edta \u00e1. A\u00f0 auki l\u00fdsir hann \u00feeirri von sinni, a\u00f0 hann geti nota\u00f0 a\u00f0fer\u00f0irnar til a\u00f0 \u00e1kvar\u00f0a braut halastj\u00f6rnunnar, sem hann s\u00e1 hausti\u00f0 1838. Ekki veit \u00e9g hvort s\u00fa r\u00e1\u00f0ager\u00f0 heppna\u00f0ist, en gaman v\u00e6ri a\u00f0 vita, hvort einhvers sta\u00f0ar s\u00e9 a\u00f0 finna fleiri af \u00feeim br\u00e9fum, sem f\u00f3ru milli \u00feeirra f\u00e9laga um stj\u00f6rnufr\u00e6\u00f0i.<\/p>\n<ul>\n<li>Bj\u00f6rn Gunnlaugsson, 1862: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=2024304\">J\u00f3n Bjarnason \u00ed \u00de\u00f3rormst\u00fangu<\/a>.<\/li>\n<li>Wikipedia:\u00a0<a href=\"https:\/\/en.wikipedia.org\/wiki\/Comet_Encke\">Encke&#8217;s comet.<\/a><\/li>\n<li>G. W. Kron: <a href=\"http:\/\/cometography.com\/pcomets\/002p.html\">2P\/Encke.<\/a><\/li>\n<\/ul>\n<hr \/>\n<p><strong>\u25ca <a href=\"https:\/\/en.wikipedia.org\/wiki\/Comet_Donati\">Donati halastjarnan 1858:<\/a><\/strong><\/p>\n<p>\u00deessari halastj\u00f6rnu hafa veri\u00f0 ger\u00f0 \u00edtarleg skil <a href=\"https:\/\/uni.hi.is\/einar\/2018\/06\/24\/halastjarnan-mikla-arid-1858-maelingar-og-hughrif-i-upphafi-nyrra-tima-i-stjornufraedi\/\">\u00ed fyrri f\u00e6rslu<\/a> og leyfi \u00e9g m\u00e9r a\u00f0 v\u00edsa lesendum \u00feanga\u00f0.<\/p>\n<ul>\n<li>Bj\u00f6rn Gunnlaugsson, 1858: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=2023785\">Halastjarnan 1858<\/a>.<\/li>\n<li>Benedikt Gr\u00f6ndal, 1858: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=2018621\">Halastjarnan 1858<\/a>.<\/li>\n<li>Einar H. Gu\u00f0mundsson, 2018:\u00a0 <a href=\"http:\/\/uni.hi.is\/einar\/2018\/06\/24\/halastjarnan-mikla-arid-1858-maelingar-og-hughrif-i-upphafi-nyrra-tima-i-stjornufraedi\/\">Halastjarnan mikla \u00e1ri\u00f0 1858 &#8211; M\u00e6lingar og hughrif \u00ed upphafi n\u00fdrra t\u00edma \u00ed stj\u00f6rnufr\u00e6\u00f0i.<\/a><\/li>\n<li>A. Gasperini, D. Galli og L. Nenzi, 2011: <a href=\"https:\/\/arxiv.org\/pdf\/1211.3859.pdf\">The worldwide impact of Donati\u2019s comet on art and society in the mid-19th century.<\/a><\/li>\n<\/ul>\n<hr \/>\n<p><strong>\u25ca Loftsj\u00f3nin \u00ed n\u00f3vember 1866:<\/strong><\/p>\n<p>\u00deri\u00f0judaginn 27. n\u00f3vember 1866 birtist \u00ed <em>\u00dej\u00f3\u00f0\u00f3lfi<\/em> stutt fr\u00e1s\u00f6gn af\u00a0 hrinu stj\u00f6rnuhrapa, sem s\u00e9st haf\u00f0i \u00ed Reykjav\u00edk\u00a0 n\u00f3ttina 13. til 14. n\u00f3vember. \u00dear segir me\u00f0al annars:<\/p>\n<blockquote><p>A\u00f0 kveldi 13. \u00feessa m\u00e1na\u00f0ar s\u00e1st h\u00e9r \u00ed Reykjaiv\u00edk f\u00f6gr loptsj\u00f3n. <em>[\u2026]<\/em> N\u00e6trver\u00f0ir b\u00e6arins komu \u00e1 str\u00e6tin kl. 10 um kveldi\u00f0 og t\u00f3ku \u00feegar eptir \u00fev\u00ed, a\u00f0 stj\u00f6rnuhr\u00f6p \u00ed frekara lagi s\u00e1ust um austrlopti\u00f0; a\u00f0rir menn s\u00e1tu inni og vissu svo eigi hva\u00f0 \u00fati gj\u00f6r\u00f0ist. \u00deessi stj\u00f6rnuhr\u00f6p f\u00f3ru alltaf vaxaudi, og \u00feegar kom fram um 11. stund voru \u00feau m\u00f6rg \u00e1 lopti \u00ed einu, ofar og ne\u00f0ar \u00ed lopti og til beggja hli\u00f0a; \u00de\u00e1 ur\u00f0u nokkrir a\u00f0rir menn h\u00e9r \u00ed b\u00e6num \u00feessa varir, og horf\u00f0u \u00e1 um stund; h\u00e9r um bil kl. 12 st\u00f3\u00f0 \u00feetta sem h\u00e6zt, en s\u00ed\u00f0an f\u00f3r \u00fea\u00f0 heldr m\u00ednkandi. <em>[\u2026]<\/em> \u00deessi loptlj\u00f3s komu \u00far nor\u00f0austri (landnor\u00f0ri) og flugu upp \u00e1 lopti\u00f0 til su\u00f0vestrs (\u00fatsu\u00f0rs). <em>[\u2026]<\/em> \u00d6ll voru \u00feau sm\u00e1, eins og venjuleg stj\u00f6rnuhr\u00f6p, nema eitt, \u00fea\u00f0 var allmikill eldhn\u00f6ttr (v\u00edgahn\u00f6ttr?) og l\u00fdsti mj\u00f6g af, er hann \u00feaut upp \u00e1 lopti\u00f0, en \u00fear hvarf hann; eigi heyr\u00f0u \u00feeir \u00feyt e\u00f0a bresti til \u00feessara loptsj\u00f3na, en mj\u00f6g haf\u00f0i sj\u00f3n \u00feessi veri\u00f0 f\u00f6gr.<\/p><\/blockquote>\n<p>\u00dearna var um a\u00f0 r\u00e6\u00f0a <a href=\"https:\/\/en.wikipedia.org\/wiki\/Meteor_shower\">loftsteinadr\u00edfu<\/a>, sem k\u00f6llu\u00f0 er <a href=\"https:\/\/en.wikipedia.org\/wiki\/Leonids\">Leon\u00edtar<\/a>, en \u00fea\u00f0 nafn kom til s\u00ed\u00f0ar. \u00cd pistlinum, sem P\u00e1ll Melste\u00f0 skrifa\u00f0i, \u00fatsk\u00fdrir hann fyrirb\u00e6ri\u00f0 eftir bestu getu. Sk\u00fdring hans er \u00ed meginatri\u00f0um hin sama og \u00e1\u00f0ur haf\u00f0i komi\u00f0 fram \u00ed \u00f6\u00f0rum hluta greinar Bj\u00f6rns Gunnlaugssonar um v\u00edgahn\u00f6ttin mikla \u00ed okt\u00f3ber 1851. \u00dear segir Bj\u00f6rn og hefur eftir kennslub\u00f3k \u00feeirra Pouillets og M\u00fcllers (2. hefti, bls. 608-09):<\/p>\n<blockquote><p>Menn geta varla lengur efast um a\u00f0 stj\u00f6rnuhr\u00f6p, v\u00edgahnettir og loptsteinar hafi cosmiskan uppruna, e\u00f0a sjeu til or\u00f0nir, sem reykistj\u00f6rnurnar, a\u00f0 \u00feeir a\u00f0 l\u00edkindum sjeu himinl\u00edkamir, sem fari \u00ed kring um s\u00f3lina og detti ni\u00f0ur \u00e1 j\u00f6r\u00f0ina, \u00feegar \u00feeir komast inn \u00ed hennar a\u00f0dr\u00e1ttarsvi\u00f0. <em>[\u2026]<\/em> \u00deegar menn gj\u00f6ra r\u00e1\u00f0 fyrir, a\u00f0 auk hinna \u00f3teljandi \u00feess h\u00e1ttar kroppa, sem einstakir renna \u00ed kring um s\u00f3lina, \u00fe\u00e1 sjeu l\u00edka til skarar af \u00feeim, sem gj\u00f6ri hring i kring um s\u00f3lina, og a\u00f0 fl\u00f6tur \u00feessa hrings snei\u00f0i jar\u00f0arinnar ganghring \u00e1 vissum sta\u00f0, \u00fe\u00e1 ver\u00f0ur manni skiljanlegt hvernig standi \u00e1 \u00feeim stj\u00f6rnuhr\u00f6pum, er koma \u00e1 vissum t\u00edmum \u00e1rsins.<\/p><\/blockquote>\n<figure id=\"attachment_7163\" aria-describedby=\"caption-attachment-7163\" style=\"width: 330px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-7163\" src=\"http:\/\/uni.hi.is\/einar\/files\/2018\/08\/Leonids-1833-196x300.jpg\" alt=\"\" width=\"330\" height=\"505\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/Leonids-1833-196x300.jpg 196w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/08\/Leonids-1833.jpg 391w\" sizes=\"auto, (max-width: 330px) 100vw, 330px\" \/><figcaption id=\"caption-attachment-7163\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">Sk\u00e6\u00f0adr\u00edfa stj\u00f6rnuhrapa yfir sm\u00e1b\u00e6 \u00ed N\u00fdja Englandi hinn 13. n\u00f3vember 1833. \u00dearna var \u00fev\u00ed um Leon\u00edta a\u00f0 r\u00e6\u00f0a. Ekki er lj\u00f3st hversu n\u00e1kv\u00e6m myndin er, \u00fev\u00ed h\u00fan var teiknu\u00f0 54 \u00e1rum eftir atbur\u00f0inn. Teiknarinn var Karl Jauslin.<\/span><\/figcaption><\/figure>\n<ul>\n<li>P\u00e1ll Melsted, 1866: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=2025259\">Loptsj\u00f3n.<\/a><\/li>\n<li>P\u00e1ll Melsted, 1867: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=2025308\">Loptsj\u00f3n-framhald.<\/a><\/li>\n<li>Bj\u00f6rn Gunnlaugsson, 1852: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=2035440\"> Um loptsj\u00f3n, er s\u00e1st \u00e1 n\u0153stli\u00f0num vetri, \u00feann 26. Octobris-1. hluti<\/a>, <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=2035451\">2. hluti<\/a>, <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=2035458\">3. hluti<\/a>.<\/li>\n<li>J. M\u00fcller, 1845: <a href=\"https:\/\/books.google.is\/books?id=aAlQAAAAYAAJ&amp;source=gbs_navlinks_s\">Pouillet&#8217;s Lehrbuch der Physik und Meteorologie<\/a>, Zweiter Band.<\/li>\n<\/ul>\n<p>Hvorki Bj\u00f6rn n\u00e9 P\u00e1ll minnast einu or\u00f0i \u00e1 samband loftsteinadr\u00edfa og halastjarna. Ekki er heldur vi\u00f0 \u00fev\u00ed a\u00f0 b\u00faast, \u00fev\u00ed \u00fe\u00f3tt hugmyndir um sl\u00edk tengsl hafi veri\u00f0 til umr\u00e6\u00f0u me\u00f0al stj\u00f6rnufr\u00e6\u00f0inga allt fr\u00e1 \u00fev\u00ed \u00e1 fj\u00f3r\u00f0a \u00e1ratugnum, var \u00fea\u00f0 ekki fyrr en \u00e1ri\u00f0 1866, sem m\u00f6nnum t\u00f3kst \u00ed fyrsta sinn a\u00f0 s\u00fdna fram \u00e1 \u00feau v\u00e6ru til sta\u00f0ar.<\/p>\n<p>\u00cd greinum, sem birtust \u00e1 \u00e1runum 1866-67, s\u00fdndi <a href=\"https:\/\/en.wikipedia.org\/wiki\/Giovanni_Schiaparelli\">G. Schiaparelli<\/a> fram \u00e1, a\u00f0\u00a0<a href=\"https:\/\/en.wikipedia.org\/wiki\/Perseids\">Pers\u00edtarnir<\/a> \u00e6ttu \u00e6ttir a\u00f0 rekja til <a href=\"https:\/\/en.wikipedia.org\/wiki\/Comet_Swift%E2%80%93Tuttle\">Swift-Tuttle<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Comet_Swift%E2%80%93Tuttle\"> halastj\u00f6rnunnar<\/a>.\u00a0 \u00c1ri\u00f0 1867 f\u00e6r\u00f0i <a href=\"https:\/\/de.wikipedia.org\/wiki\/Carl_Friedrich_Wilhelm_Peters\">C. F. W.Peters<\/a> svo fram sterk r\u00f6k fyrir \u00fev\u00ed a\u00f0 <a href=\"https:\/\/en.wikipedia.org\/wiki\/55P\/Tempel%E2%80%93Tuttle\">Tempel-Tuttle halastjarnan<\/a> v\u00e6ri m\u00f3\u00f0ir Le\u00f3n\u00edtanna og um svipa\u00f0 leyti s\u00fdndi <a href=\"https:\/\/de.wikipedia.org\/wiki\/Edmund_Weiss\">E. Weiss<\/a> fram \u00e1 a\u00f0 hi\u00f0 sama \u00e6tti vi\u00f0, annars vegar um\u00a0<a href=\"https:\/\/en.wikipedia.org\/wiki\/C\/1861_G1_(Thatcher)\">Thatcher halastj\u00f6rnuna<\/a> og <a href=\"https:\/\/en.wikipedia.org\/wiki\/Lyrids\">L\u00fdr\u00edta<\/a> og hins vegar um <a href=\"https:\/\/en.wikipedia.org\/wiki\/Biela%27s_Comet\">Biela halastj\u00f6rnuna<\/a> og <a href=\"https:\/\/en.wikipedia.org\/wiki\/Andromedids\">Andr\u00f3med\u00edta<\/a> (Biela-stjarnan var \u00fe\u00e1 reyndar horfin).<\/p>\n<p>\u00cd grein sinni um halastj\u00f6rnur og stj\u00f6rnuhr\u00f6p fr\u00e1 \u00e1rinu 1883 l\u00fdsir \u00deorvaldur Thoroddsen \u00feessum \u00e6ttartengslum svo:<\/p>\n<blockquote><p>Er \u00fea\u00f0 \u00e6tlun manna, a\u00f0 halastj\u00f6rnur og stj\u00f6rnuhr\u00f6p standi \u00ed n\u00e1nu sambandi hvort vi\u00f0 anna\u00f0. Schiaparelli og a\u00f0rir n\u00e1tt\u00farufr\u00e6\u00f0ingar eru \u00fev\u00ed \u00e1 eitt s\u00e1ttir me\u00f0 \u00fea\u00f0, a\u00f0 \u00feegar halastjarna heldur braut s\u00edna, skilist fr\u00e1 henni s\u00ed og \u00e6 eint\u00f3mar sm\u00e1agnir, er ver\u00f0a eptir \u00e1 brautinni, en fara sama hring og m\u00f3\u00f0ir \u00feeirra; \u00feetta s\u00e9st af \u00fev\u00ed, a\u00f0 brautirnar eru sameiginlegar fyrir stj\u00f6rnuhr\u00f6pin og halastj\u00f6rnurnar. \u00deegar halastj\u00f6rnur ey\u00f0ast, er mj\u00f6g l\u00edklegt a\u00f0 \u00fe\u00e6r ver\u00f0i a\u00f0 eint\u00f3mum sm\u00e1\u00f6gnum, og svo hefir efalaust veri\u00f0 me\u00f0 Biela&#8217;s stj\u00f6rnu.<\/p><\/blockquote>\n<ul>\n<li>\u00deorvaldur Thoroddsen, 1883: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?gegnirId=000587484\">Halastj\u00f6rnur og stj\u00f6rnuhr\u00f6p<\/a>.<\/li>\n<li>I. W. Williams, 2011: <a href=\"https:\/\/academic.oup.com\/astrogeo\/article\/52\/2\/2.20\/206512\">The origin and evolution of meteor showers and meteoroid streams.<\/a>\u00a0 \u00c1g\u00e6tis s\u00f6guyfirlit.<\/li>\n<li>\u00deorsteinn S\u00e6mundsson, 2017: <a href=\"http:\/\/www.almanak.hi.is\/loftsteinar\/loftrabb.html\">Loftsteinar<\/a>.<\/li>\n<li>D. W. Hughes, 1995: <a href=\"http:\/\/adsbit.harvard.edu\/\/full\/1995EM%26P...68...31H\/0000031.000.html\">The Perseid Meteor Shower.<\/a><\/li>\n<\/ul>\n<p>Nokkrar \u00edslenskar greinar um svipa\u00f0 efni:<\/p>\n<ul>\n<li>\u00deorvaldur Thoroddsen, 1886: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=2317276\">(Stj\u00f6rnuhr\u00f6p.)<\/a>\u00a0 \u00dearna voru Andr\u00f3med\u00edtar \u00e1 fer\u00f0.<\/li>\n<li>P\u00e1ll Bjarnason, 1934: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=4263287\">Stj\u00f6rnuhr\u00f6pin \u00ed Vestmannaeyjum.<\/a> \u00deessi loftsteinadr\u00edfa heitir <a href=\"https:\/\/en.wikipedia.org\/wiki\/Draconids\">Drakon\u00edtar<\/a>.<\/li>\n<li>\u00c1rni Fri\u00f0riksson, 1934: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?gegnirId=000503858\">Um stj\u00f6rnuhr\u00f6p.<\/a> \u00de\u00fddd \u00ed framhaldi af grein P\u00e1ls.<\/li>\n<li>\u00deorsteinn S\u00e6mundsson, 2008: <a href=\"http:\/\/www.almanak.hi.is\/vigahnot.html\">\u00d3venjulegur v\u00edgahn\u00f6ttur yfir \u00cdslandi.<\/a><\/li>\n<\/ul>\n<hr \/>\n<p><strong>\u25ca <a href=\"https:\/\/de.wikipedia.org\/wiki\/C\/1882_F1_(Wells)\">Wells halastjarnan 1882:<\/a><\/strong><\/p>\n<p>Ekki m\u00e1 rugla Wells-stj\u00f6rnunni saman vi\u00f0\u00a0 <a href=\"https:\/\/en.wikipedia.org\/wiki\/Great_Comet_of_1882\">halastj\u00f6rnuna miklu \u00e1ri\u00f0 1882<\/a>, sem ekki vir\u00f0ist hafa s\u00e9st h\u00e9r \u00e1 landi. Reyndar var Wells-stjarnan bj\u00f6rtust \u00ed j\u00fan\u00edm\u00e1nu\u00f0i og hefur \u00fev\u00ed a\u00f0 \u00f6llum l\u00edkindum ekki heldur s\u00e9st h\u00e9r heima. Hins vegar er til skemmtileg l\u00fdsing \u00e1 stj\u00f6rnunni, sem birtist \u00ed <em>\u00cdsafold<\/em> \u00ed j\u00fal\u00ed \u00feetta \u00e1r. \u00dear segir me\u00f0al annars:<\/p>\n<blockquote><p>\u00c1 lei\u00f0inni milli Orkneyja og F\u00e6reyja s\u00e1um vjer far\u00feegjar me\u00f0 p\u00f3stskipinu \u201eValdemar\u201c stj\u00f6rnuna me\u00f0 beru auga, oss til mikils gamans; \u00feetta var kv\u00f6ldi\u00f0 2. j\u00fan\u00ed kl. <em>[11:30]<\/em>; ve\u00f0ur var gott, hei\u00f0ur himinn og lopti\u00f0 bjart af dagsbr\u00fan \u00ed nor\u00f0ri og vestri, eigi a\u00f0 s\u00ed\u00f0ur s\u00e1st stjarnan n\u00e1l\u00e6gt h\u00e1nor\u00f0ri, skammt fr\u00e1 s\u00f3lunni, sp\u00f6lkorn fyrir ofan hafsbr\u00fanina. H\u00fan var silfurbj\u00f6rt a\u00f0 lit \u2014 ekki rau\u00f0leit \u2014 og \u00e1 st\u00e6r\u00f0 vi\u00f0 stj\u00f6rnu \u00ed \u00f6\u00f0rum flokki; me\u00f0al annars var \u00fea\u00f0 merkilegt, a\u00f0 halinn, sem var talsvert langur, st\u00f3\u00f0 l\u00f3\u00f0rjett upp, en ekki aptur af henni, eins og \u00e1 halastj\u00f6rnu \u00feeirri, er s\u00e1st hjer \u00e1 landi \u00e1ri\u00f0 1858.<\/p><\/blockquote>\n<ul>\n<li>Tr. G., 1882: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=3940345\">N\u00fd halastjarna<\/a>.<\/li>\n<li>W. W. Payne, 1883: <a href=\"http:\/\/adsbit.harvard.edu\/\/full\/1883SidM....2..119P\/0000119.000.html\">The Comets of 1882.<\/a><\/li>\n<\/ul>\n<hr \/>\n<h3 style=\"text-align: center\"><span style=\"font-size: 14pt\">Framhaldsf\u00e6rslur:<\/span><\/h3>\n<ul>\n<li>Halastj\u00f6rnur fyrr og n\u00fa &#8211; 3. Tuttugasta \u00f6ld.<\/li>\n<li>Halastj\u00f6rnur fyrr og n\u00fa &#8211; 4. Upphaf tuttugustu og fyrstu aldar (me\u00f0 lista yfir \u00fdmsar a\u00f0rar gagnlegar vefs\u00ed\u00f0ur og ritsm\u00ed\u00f0ar).<\/li>\n<\/ul>\n<hr \/>\n<hr \/>\n<p class=\"x_MsoNormal\"><span style=\"font-size: 10pt\"><strong>Vi\u00f0b\u00f3t 1<\/strong> (16. n\u00f3v. 2018):\u00a0 \u00cd g\u00e6r barst m\u00e9r eftirfarandi skeyti fr\u00e1 Trausta J\u00f3nssyni ve\u00f0urfr\u00e6\u00f0ingi: \u201e<em>Rakst \u00e1 \u00feetta \u00ed dagb\u00f3k J\u00f3ns J\u00f3nssonar \u00e1 M\u00f6\u00f0rufelli \u2013 \u00ed lok \u00e1rsins 1811. Handriti\u00f0 er n\u00famer \u00edbr84 8vo og myndin af s\u00ed\u00f0u 359 (\u00ed myndger\u00f0 handritsins). \u00c9g s\u00e1 a\u00f0 J\u00f3n var b\u00fainn a\u00f0 geta um halastj\u00f6rnu \u00ed september.<\/em>\u201c Me\u00f0 skeytinu fylgdi \u00feessi mynd:<\/span><\/p>\n<figure id=\"attachment_9161\" aria-describedby=\"caption-attachment-9161\" style=\"width: 449px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-9161\" src=\"http:\/\/uni.hi.is\/einar\/files\/2018\/11\/cometa_1811_jon-jonsson-copy-256x300.jpg\" alt=\"\" width=\"449\" height=\"526\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/11\/cometa_1811_jon-jonsson-copy-256x300.jpg 256w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/11\/cometa_1811_jon-jonsson-copy-875x1024.jpg 875w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/11\/cometa_1811_jon-jonsson-copy-768x899.jpg 768w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/11\/cometa_1811_jon-jonsson-copy.jpg 1012w\" sizes=\"auto, (max-width: 449px) 100vw, 449px\" \/><figcaption id=\"caption-attachment-9161\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">L\u00fdsing <a href=\"https:\/\/is.wikipedia.org\/wiki\/J%C3%B3n_J%C3%B3nsson_l%C3%A6r%C3%B0i\">J\u00f3ns l\u00e6r\u00f0a<\/a> \u00e1 braut halastj\u00f6rnnnar 1811 \u00e1 hvelfingunni \u00e1 t\u00edmabilinu 7. n\u00f3vember til 12. desember 1811. Til vi\u00f0mi\u00f0unar \u00e1 teikningunni eru stj\u00f6rnurnar <a href=\"https:\/\/en.wikipedia.org\/wiki\/Vega\">Vega<\/a> \u00ed <a href=\"https:\/\/www.stjornufraedi.is\/stjornuskodun\/stjornumerkin\/harpan\/\">H\u00f6rpunni<\/a> og <a href=\"https:\/\/en.wikipedia.org\/wiki\/Altair\">Altair<\/a> \u00ed <a href=\"https:\/\/www.stjornufraedi.is\/stjornuskodun\/stjornumerkin\/orninn\/\">Erninum<\/a>.<\/span><\/figcaption><\/figure>\n<div>\n<div lang=\"IS\">\n<div class=\"x_WordSection1\">\n<p class=\"x_MsoNormal\"><span style=\"font-size: 10pt\">Til samanbur\u00f0ar m\u00e1 benda \u00e1 \u00edtarlegri umfj\u00f6llun um brautina hj\u00e1 R. Stoyan, 2015: <a href=\"https:\/\/books.google.is\/books?id=WAZEBgAAQBAJ&amp;source=gbs_navlinks_s\">Atlas of Great Comets,<\/a> bls. 110-114. Eftirfarandi teikning er \u00e1 bls. 111:<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-9162 aligncenter\" src=\"http:\/\/uni.hi.is\/einar\/files\/2018\/11\/Comet1811-300x137.png\" alt=\"\" width=\"641\" height=\"293\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/11\/Comet1811-300x137.png 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/11\/Comet1811-768x352.png 768w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2018\/11\/Comet1811.png 836w\" sizes=\"auto, (max-width: 641px) 100vw, 641px\" \/><\/p>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>\u00deessi f\u00e6rsla er \u00f6nnur \u00ed r\u00f6\u00f0inni af fj\u00f3rum og beint framhald af \u00feeirri fyrstu: Halastj\u00f6rnur fyrr og n\u00fa &#8211; 1. Fr\u00e1 mi\u00f0\u00f6ldum til loka sautj\u00e1ndu aldar. \u00c1 \u00e1tj\u00e1ndu \u00f6ld og fyrri hluta \u00feeirrar n\u00edtj\u00e1ndu snerust ranns\u00f3knir \u00e1 halastj\u00f6rnum fyrst og fremst um leitina a\u00f0 n\u00fdjum lei\u00f0um til \u00feess a\u00f0 \u00e1kvar\u00f0a brautir \u00feeirra me\u00f0 sem mestri [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,4,8,14,15],"tags":[],"class_list":["post-6719","post","type-post","status-publish","format-standard","hentry","category-atjanda-oldin","category-edlisfraedi","category-nitjanda-old","category-staerdfraedi","category-stjornufraedi"],"_links":{"self":[{"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=\/wp\/v2\/posts\/6719","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=6719"}],"version-history":[{"count":0,"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=\/wp\/v2\/posts\/6719\/revisions"}],"wp:attachment":[{"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6719"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6719"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6719"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}