{"id":47943,"date":"2026-10-26T04:23:21","date_gmt":"2026-10-26T04:23:21","guid":{"rendered":"https:\/\/www.worldclock.com\/siderisk-tid-kalkylator\/"},"modified":"2026-10-26T04:23:21","modified_gmt":"2026-10-26T04:23:21","slug":"siderisk-tid-kalkylator","status":"publish","type":"page","link":"https:\/\/www.worldclock.com\/sv\/siderisk-tid-kalkylator\/","title":{"rendered":"Kalkylator f\u00f6r siderisk tid och julianskt datum"},"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\/sv\/\">V\u00e4rldsklocka<\/a><\/li><li><a href=\"https:\/\/www.worldclock.com\/sv\/verktyg\/\">Tidsverktyg<\/a><\/li><li><span aria-current=\"page\">Kalkylator f\u00f6r siderisk tid och julianskt datum<\/span><\/li><\/ol><\/nav><p class=\"wc-eyebrow\"><span aria-hidden=\"true\">\ud83c\udf0c<\/span> Gratis verktyg<\/p><h1 class=\"wc-thero__title\">Kalkylator f\u00f6r siderisk tid och julianskt datum<\/h1><p class=\"wc-thero__lead\">Lokal siderisk tid live, Greenwich siderisk tid, julianskt datum och modifierat julianskt datum f\u00f6r valfri plats och tid.<\/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>Plats<\/span><div class=\"wc-search wc-search--tool\" data-wc-search data-mode=\"add\"><input type=\"search\" placeholder=\"S\u00f6k en stad\u2026\" aria-label=\"S\u00f6k en stad\u2026\" autocomplete=\"off\"><ul class=\"wc-search__results\" hidden><\/ul><\/div><\/div><label class=\"wc-field\"><span>Longitud \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 Anv\u00e4nd min plats<\/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>Omvandla ett datum<\/h2><label class=\"wc-field\"><span>Datum &amp; tid (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>Vad \u00e4r siderisk tid (stj\u00e4rntid)?<\/h2><p>Siderisk tid m\u00e4ter jordens rotation i f\u00f6rh\u00e5llande till de avl\u00e4gsna stj\u00e4rnorna i st\u00e4llet f\u00f6r solen. Ett sideriskt dygn \u00e4r ungef\u00e4r <strong>23 timmar 56 minuter 4 sekunder<\/strong> \u2013 n\u00e4stan fyra minuter kortare \u00e4n ett soldygn \u2013 s\u00e5 stj\u00e4rnorna g\u00e5r upp fyra minuter tidigare varje natt. Astronomer anv\u00e4nder <strong>lokal siderisk tid (LST)<\/strong> f\u00f6r att rikta teleskop: en stj\u00e4rna st\u00e5r h\u00f6gst p\u00e5 himlen n\u00e4r LST \u00e4r lika med dess rektascension.<\/p><p><strong>Julianskt datum<\/strong> \u00e4r en l\u00f6pande r\u00e4kning av dagar sedan mitt p\u00e5 dagen UTC den 1 januari 4713 f.Kr., som anv\u00e4nds inom astronomin f\u00f6r att undvika kalenderkomplikationer. <strong>Modifierat julianskt datum<\/strong> (MJD) \u00e4r JD \u2212 2 400 000,5 och b\u00f6rjar vid midnatt.<\/p><\/div><\/section><section class=\"wc-section wc-faq\"><h2>Vanliga fr\u00e5gor<\/h2><details><summary>Hur r\u00e4knar jag ut lokal siderisk tid?<\/summary><p>R\u00e4kna ut Greenwich siderisk medeltid fr\u00e5n det julianska datumet och l\u00e4gg sedan till din longitud i timmar (longitud \u00f7 15, \u00f6ster positivt). Kalkylatorn ovan g\u00f6r det live f\u00f6r valfri plats.<\/p><\/details><\/section><section class=\"wc-section wc-tools-grid\"><div class=\"wc-section__head\"><h2>Fler gratis tidsverktyg<\/h2><a href=\"https:\/\/www.worldclock.com\/sv\/verktyg\/\">Alla verktyg \u2192<\/a><\/div><div class=\"wc-toolcards\"><a class=\"wc-toolcard wc-toolcard--sun\" href=\"https:\/\/www.worldclock.com\/sv\/soluppgang-solnedgang\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83c\udf05<\/span><span class=\"wc-toolcard__name\">Kalkylator f\u00f6r soluppg\u00e5ng och solnedg\u00e5ng<\/span><span class=\"wc-toolcard__desc\">Soluppg\u00e5ng, solnedg\u00e5ng och gyllene timmen.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--golden\" href=\"https:\/\/www.worldclock.com\/sv\/gyllene-timmen\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83d\udcf8<\/span><span class=\"wc-toolcard__name\">Gyllene timmen-kalkylator<\/span><span class=\"wc-toolcard__desc\">B\u00e4sta ljuset f\u00f6r foton.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--moon\" href=\"https:\/\/www.worldclock.com\/sv\/manfas\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83c\udf15<\/span><span class=\"wc-toolcard__name\">M\u00e5nfas idag<\/span><span class=\"wc-toolcard__desc\">Kv\u00e4llens m\u00e5ne och m\u00e5nkalender.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--fullmoon\" href=\"https:\/\/www.worldclock.com\/sv\/fullmanekalender\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83c\udf1d<\/span><span class=\"wc-toolcard__name\">Fullm\u00e5nekalender<\/span><span class=\"wc-toolcard__desc\">Datum och namn f\u00f6r fullm\u00e5nar.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--moonrise\" href=\"https:\/\/www.worldclock.com\/sv\/manuppgang-mannedgang\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83c\udf19<\/span><span class=\"wc-toolcard__name\">M\u00e5nuppg\u00e5ng och m\u00e5nnedg\u00e5ng<\/span><span class=\"wc-toolcard__desc\">N\u00e4r m\u00e5nen g\u00e5r upp och ner.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--birthmoon\" href=\"https:\/\/www.worldclock.com\/sv\/manfas-fodelsedag\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83c\udf82<\/span><span class=\"wc-toolcard__name\">M\u00e5nen p\u00e5 din f\u00f6delsedag<\/span><span class=\"wc-toolcard__desc\">M\u00e5nen p\u00e5 valfritt datum.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--astro\" href=\"https:\/\/www.worldclock.com\/sv\/astronomisk-kalender\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83d\udd2d<\/span><span class=\"wc-toolcard__name\">Astronomisk kalender<\/span><span class=\"wc-toolcard__desc\">F\u00f6rm\u00f6rkelser, meteorer och himlafenomen.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--converter\" href=\"https:\/\/www.worldclock.com\/sv\/tidszonsomvandlare\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83d\udd01<\/span><span class=\"wc-toolcard__name\">Tidszonsomvandlare<\/span><span class=\"wc-toolcard__desc\">Omvandla en tid mellan valfria st\u00e4der.<\/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-47943","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\/sv\/author\/clocker\/"},"comment_info":"","_links":{"self":[{"href":"https:\/\/www.worldclock.com\/sv\/wp-json\/wp\/v2\/pages\/47943","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.worldclock.com\/sv\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.worldclock.com\/sv\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.worldclock.com\/sv\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.worldclock.com\/sv\/wp-json\/wp\/v2\/comments?post=47943"}],"version-history":[{"count":0,"href":"https:\/\/www.worldclock.com\/sv\/wp-json\/wp\/v2\/pages\/47943\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.worldclock.com\/sv\/wp-json\/wp\/v2\/media?parent=47943"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}