Kdybyste ka\u017ed\u00fd den ve stejnou dobu vy\u0161li ven a po\u0159\u00eddili sn\u00edmek, na kter\u00e9m by bylo vid\u011bt Slunce, jak by se m\u011bnila jeho poloha? Vizu\u00e1ln\u00ed odpov\u011bd\u00ed na tuto ot\u00e1zku je analemma, tedy kompozitn\u00ed sn\u00edmek po\u0159\u00edzen\u00fd ze stejn\u00e9ho m\u00edsta ve stejnou dobu v pr\u016fb\u011bhu cel\u00e9ho roku. Zobrazen\u00e9 analemma bylo sestaveno ze sn\u00edmk\u016f po\u0159\u00edzen\u00fdch ka\u017ed\u00fdch n\u011bkolik dn\u00ed v poledne pobl\u00ed\u017e vesnice Callanish na Vn\u011bj\u0161\u00edch Hebrid\u00e1ch ve Skotsku, Velk\u00e1 Brit\u00e1nie. V pop\u0159ed\u00ed jsou Callanishsk\u00e9 kameny, kamenn\u00fd kruh postaven\u00fd kolem roku 2700 p\u0159. n. l. b\u011bhem bronzov\u00e9 doby. Nen\u00ed zn\u00e1mo, zda m\u00e1 nebo m\u011blo uspo\u0159\u00e1d\u00e1n\u00ed Callanishsk\u00fdch kamen\u016f astronomick\u00fd v\u00fdznam. Hlavn\u00edmi p\u0159\u00ed\u010dinami tvaru \u010d\u00edsla 8 u tohoto i v\u0161ech ostatn\u00edch analem je sklon zemsk\u00e9 osy a eliptick\u00fd tvar ob\u011b\u017en\u00e9 dr\u00e1hy Zem\u011b kolem Slunce. P\u0159i slunovratech se Slunce objev\u00ed v horn\u00ed nebo doln\u00ed \u010d\u00e1sti analemmy. P\u0159edlo\u017een\u00fd sn\u00edmek byl po\u0159\u00edzen v obdob\u00ed prosincov\u00e9ho slunovratu, a proto se Slunce objevuje bl\u00edzko spodn\u00ed \u010d\u00e1sti. Rovnodennosti v\u0161ak odpov\u00eddaj\u00ed st\u0159edov\u00fdm bod\u016fm analemmy \u2013 nikoli bodu pr\u016fse\u010d\u00edku. Za dva dny nastane rovnodennost (\u201erovn\u00e1 noc\u201c), kdy budou den a noc na cel\u00e9 planet\u011b Zemi stejn\u011b dlouh\u00e9. Mnoho kultur slav\u00ed p\u0159i rovnodennosti zm\u011bnu ro\u010dn\u00edho obdob\u00ed. Hlavn\u00ed str\u00e1nka APOD na webu NASA se st\u011bhuje: Z adresy apod.nasa.gov na science.nasa.gov\/apod<\/p>\n
<\/p>\n
**Credit**: Giuseppe Petricca<\/p>\n","protected":false},"excerpt":{"rendered":"
Kdybyste ka\u017ed\u00fd den ve stejnou dobu vy\u0161li ven a po\u0159\u00eddili sn\u00edmek, na kter\u00e9m by bylo vid\u011bt Slunce, jak by se m\u011bnila jeho poloha? Vizu\u00e1ln\u00ed odpov\u011bd\u00ed na tuto ot\u00e1zku je analemma, […]<\/p>\n","protected":false},"author":1,"featured_media":4082,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-4081","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-nasa"],"_links":{"self":[{"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/posts\/4081","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/comments?post=4081"}],"version-history":[{"count":0,"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/posts\/4081\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/media\/4082"}],"wp:attachment":[{"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/media?parent=4081"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/categories?post=4081"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/tags?post=4081"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}