{"id":47687,"date":"2026-10-26T04:21:38","date_gmt":"2026-10-26T04:21:38","guid":{"rendered":"https:\/\/www.worldclock.com\/kalkulacka-hvezdneho-casu\/"},"modified":"2026-10-26T04:21:38","modified_gmt":"2026-10-26T04:21:38","slug":"kalkulacka-hvezdneho-casu","status":"publish","type":"page","link":"https:\/\/www.worldclock.com\/cs\/kalkulacka-hvezdneho-casu\/","title":{"rendered":"Kalkula\u010dka hv\u011bzdn\u00e9ho \u010dasu a juli\u00e1nsk\u00e9ho data"},"content":{"rendered":"<div class=\"wc wc-tool-page wc-tool-page--sidereal\"><header class=\"wc-thero\"><div class=\"wc-thero__text\"><nav class=\"wc-crumbs\" aria-label=\"Breadcrumb\"><ol><li><a href=\"https:\/\/www.worldclock.com\/cs\/\">Sv\u011btov\u00fd \u010das<\/a><\/li><li><a href=\"https:\/\/www.worldclock.com\/cs\/nastroje\/\">\u010casov\u00e9 n\u00e1stroje<\/a><\/li><li><span aria-current=\"page\">Kalkula\u010dka hv\u011bzdn\u00e9ho \u010dasu a juli\u00e1nsk\u00e9ho data<\/span><\/li><\/ol><\/nav><p class=\"wc-eyebrow\"><span aria-hidden=\"true\">\ud83c\udf0c<\/span> N\u00e1stroj zdarma<\/p><h1 class=\"wc-thero__title\">Kalkula\u010dka hv\u011bzdn\u00e9ho \u010dasu a juli\u00e1nsk\u00e9ho data<\/h1><p class=\"wc-thero__lead\">\u017div\u00fd m\u00edstn\u00ed hv\u011bzdn\u00fd \u010das, greenwichsk\u00fd hv\u011bzdn\u00fd \u010das, juli\u00e1nsk\u00e9 datum a modifikovan\u00e9 juli\u00e1nsk\u00e9 datum pro jak\u00e9koli m\u00edsto a \u010das.<\/p><\/div><\/header><div class=\"wc-tool\"><div class=\"wc-sid\" data-wc-tool=\"sidereal\" data-default=\"{&quot;n&quot;:&quot;Greenwich&quot;,&quot;t&quot;:&quot;Europe\\\/London&quot;,&quot;f&quot;:&quot;gb&quot;,&quot;a&quot;:51.4769,&quot;o&quot;:-0.0005}\"><div class=\"wc-tbar\"><div class=\"wc-field wc-field--grow\"><span>M\u00edsto<\/span><div class=\"wc-search wc-search--tool\" data-wc-search data-mode=\"add\"><input type=\"search\" placeholder=\"Hledat m\u011bsto\u2026\" aria-label=\"Hledat m\u011bsto\u2026\" autocomplete=\"off\"><ul class=\"wc-search__results\" hidden><\/ul><\/div><\/div><label class=\"wc-field\"><span>Zem\u011bpisn\u00e1 d\u00e9lka \u00b0<\/span><input type=\"number\" step=\"0.0001\" min=\"-180\" max=\"180\" data-lng><\/label><button type=\"button\" class=\"wc-btn wc-btn--ghost\" data-geo>\ud83d\udccd Pou\u017e\u00edt mou polohu<\/button><\/div><div class=\"wc-sunc__place\" data-place><\/div><div class=\"wc-sunc__cards\" data-cards><\/div><div class=\"wc-panel\" style=\"margin-top:16px\"><h2>P\u0159ev\u00e9st datum<\/h2><label class=\"wc-field\"><span>Datum a \u010das (UTC)<\/span><input type=\"datetime-local\" step=\"1\" data-dt><\/label><dl class=\"wc-unix__out\" data-out><\/dl><\/div><\/div><\/div><section class=\"wc-section wc-tool-info\"><div class=\"wc-prose\"><h2>Co je hv\u011bzdn\u00fd \u010das?<\/h2><p>Hv\u011bzdn\u00fd \u010das m\u011b\u0159\u00ed ot\u00e1\u010den\u00ed Zem\u011b v\u016f\u010di vzd\u00e1len\u00fdm hv\u011bzd\u00e1m, nikoli v\u016f\u010di Slunci. Hv\u011bzdn\u00fd den trv\u00e1 asi <strong>23 hodin 56 minut 4 sekundy<\/strong> \u2013 t\u00e9m\u011b\u0159 o \u010dty\u0159i minuty m\u00e9n\u011b ne\u017e slune\u010dn\u00ed den \u2013 tak\u017ee hv\u011bzdy vych\u00e1zej\u00ed ka\u017edou noc o \u010dty\u0159i minuty d\u0159\u00edve. Astronomov\u00e9 pou\u017e\u00edvaj\u00ed <strong>m\u00edstn\u00ed hv\u011bzdn\u00fd \u010das (LST)<\/strong> k m\u00ed\u0159en\u00ed dalekohled\u016f: hv\u011bzda je nejv\u00fd\u0161e na obloze, kdy\u017e se LST rovn\u00e1 jej\u00ed rektascenzi.<\/p><p><strong>Juli\u00e1nsk\u00e9 datum<\/strong> je souvisl\u00fd po\u010det dn\u00ed od poledne UTC 1. ledna 4713 p\u0159. n. l., kter\u00fd se v astronomii pou\u017e\u00edv\u00e1, aby se p\u0159ede\u0161lo komplikac\u00edm s kalend\u00e1\u0159i. <strong>Modifikovan\u00e9 juli\u00e1nsk\u00e9 datum<\/strong> (MJD) je JD \u2212 2 400 000,5 a za\u010d\u00edn\u00e1 o p\u016flnoci.<\/p><\/div><\/section><section class=\"wc-section wc-faq\"><h2>\u010cast\u00e9 dotazy<\/h2><details><summary>Jak vypo\u010d\u00edtat m\u00edstn\u00ed hv\u011bzdn\u00fd \u010das?<\/summary><p>Z juli\u00e1nsk\u00e9ho data spo\u010d\u00edtejte st\u0159edn\u00ed greenwichsk\u00fd hv\u011bzdn\u00fd \u010das a p\u0159i\u010dt\u011bte svou zem\u011bpisnou d\u00e9lku v hodin\u00e1ch (d\u00e9lka \u00f7 15, v\u00fdchodn\u00ed kladn\u011b). Kalkula\u010dka v\u00fd\u0161e to d\u011bl\u00e1 \u017eiv\u011b pro jak\u00e9koli m\u00edsto.<\/p><\/details><\/section><section class=\"wc-section wc-tools-grid\"><div class=\"wc-section__head\"><h2>Dal\u0161\u00ed \u010dasov\u00e9 n\u00e1stroje zdarma<\/h2><a href=\"https:\/\/www.worldclock.com\/cs\/nastroje\/\">V\u0161echny n\u00e1stroje \u2192<\/a><\/div><div class=\"wc-toolcards\"><a class=\"wc-toolcard wc-toolcard--sun\" href=\"https:\/\/www.worldclock.com\/cs\/vychod-a-zapad-slunce\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83c\udf05<\/span><span class=\"wc-toolcard__name\">Kalkula\u010dka v\u00fdchodu a z\u00e1padu slunce<\/span><span class=\"wc-toolcard__desc\">V\u00fdchod a z\u00e1pad slunce a zlat\u00e1 hodinka.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--golden\" href=\"https:\/\/www.worldclock.com\/cs\/kalkulacka-zlate-hodinky\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83d\udcf8<\/span><span class=\"wc-toolcard__name\">Kalkula\u010dka zlat\u00e9 hodinky<\/span><span class=\"wc-toolcard__desc\">Nejlep\u0161\u00ed sv\u011btlo pro fotky.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--moon\" href=\"https:\/\/www.worldclock.com\/cs\/faze-mesice\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83c\udf15<\/span><span class=\"wc-toolcard__name\">F\u00e1ze M\u011bs\u00edce dnes<\/span><span class=\"wc-toolcard__desc\">Dne\u0161n\u00ed M\u011bs\u00edc a lun\u00e1rn\u00ed kalend\u00e1\u0159.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--fullmoon\" href=\"https:\/\/www.worldclock.com\/cs\/kalendar-uplnku\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83c\udf1d<\/span><span class=\"wc-toolcard__name\">Kalend\u00e1\u0159 \u00fapl\u0148k\u016f<\/span><span class=\"wc-toolcard__desc\">Data a n\u00e1zvy \u00fapl\u0148k\u016f.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--moonrise\" href=\"https:\/\/www.worldclock.com\/cs\/vychod-a-zapad-mesice\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83c\udf19<\/span><span class=\"wc-toolcard__name\">V\u00fdchod a z\u00e1pad M\u011bs\u00edce<\/span><span class=\"wc-toolcard__desc\">Kdy M\u011bs\u00edc vych\u00e1z\u00ed a zapad\u00e1.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--birthmoon\" href=\"https:\/\/www.worldclock.com\/cs\/faze-mesice-v-den-narozeni\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83c\udf82<\/span><span class=\"wc-toolcard__name\">M\u011bs\u00edc ve va\u0161e narozeniny<\/span><span class=\"wc-toolcard__desc\">M\u011bs\u00edc v jak\u00fdkoli den.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--astro\" href=\"https:\/\/www.worldclock.com\/cs\/astronomicky-kalendar\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83d\udd2d<\/span><span class=\"wc-toolcard__name\">Astronomick\u00fd kalend\u00e1\u0159<\/span><span class=\"wc-toolcard__desc\">Zatm\u011bn\u00ed, meteory a d\u011bn\u00ed na obloze.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--converter\" href=\"https:\/\/www.worldclock.com\/cs\/prevodnik-casovych-pasem\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83d\udd01<\/span><span class=\"wc-toolcard__name\">P\u0159evodn\u00edk \u010dasov\u00fdch p\u00e1sem<\/span><span class=\"wc-toolcard__desc\">P\u0159eve\u010fte \u010das mezi libovoln\u00fdmi m\u011bsty.<\/span><\/a><\/div><\/section><\/div>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_kad_post_classname":"","footnotes":"","bs_cache_bypass_cache":0,"bs_cache_related_page":0},"class_list":["post-47687","page","type-page","status-publish","hentry"],"acf":[],"taxonomy_info":[],"featured_image_src_large":false,"author_info":{"display_name":"clocker","author_link":"https:\/\/www.worldclock.com\/cs\/author\/clocker\/"},"comment_info":"","_links":{"self":[{"href":"https:\/\/www.worldclock.com\/cs\/wp-json\/wp\/v2\/pages\/47687","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.worldclock.com\/cs\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.worldclock.com\/cs\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.worldclock.com\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.worldclock.com\/cs\/wp-json\/wp\/v2\/comments?post=47687"}],"version-history":[{"count":0,"href":"https:\/\/www.worldclock.com\/cs\/wp-json\/wp\/v2\/pages\/47687\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.worldclock.com\/cs\/wp-json\/wp\/v2\/media?parent=47687"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}