{"id":29302,"date":"2026-10-23T08:37:09","date_gmt":"2026-10-23T08:37:09","guid":{"rendered":"https:\/\/www.worldclock.com\/tempo-siderale\/"},"modified":"2026-10-23T08:37:09","modified_gmt":"2026-10-23T08:37:09","slug":"tempo-siderale","status":"publish","type":"page","link":"https:\/\/www.worldclock.com\/it\/tempo-siderale\/","title":{"rendered":"Calcolatore di tempo siderale e data giuliana"},"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\/it\/\">Orologio mondiale<\/a><\/li><li><a href=\"https:\/\/www.worldclock.com\/it\/strumenti\/\">Strumenti per l\u2019ora<\/a><\/li><li><span aria-current=\"page\">Calcolatore di tempo siderale e data giuliana<\/span><\/li><\/ol><\/nav><p class=\"wc-eyebrow\"><span aria-hidden=\"true\">\ud83c\udf0c<\/span> Strumento gratuito<\/p><h1 class=\"wc-thero__title\">Calcolatore di tempo siderale e data giuliana<\/h1><p class=\"wc-thero__lead\">Tempo siderale locale in tempo reale, tempo siderale di Greenwich, data giuliana e data giuliana modificata per qualsiasi luogo e ora.<\/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>Localit\u00e0<\/span><div class=\"wc-search wc-search--tool\" data-wc-search data-mode=\"add\"><input type=\"search\" placeholder=\"Cerca una citt\u00e0\u2026\" aria-label=\"Cerca una citt\u00e0\u2026\" autocomplete=\"off\"><ul class=\"wc-search__results\" hidden><\/ul><\/div><\/div><label class=\"wc-field\"><span>Longitudine \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 Usa la mia posizione<\/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>Converti una data<\/h2><label class=\"wc-field\"><span>Data e ora (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>Che cos\u2019\u00e8 il tempo siderale?<\/h2><p>Il tempo siderale misura la rotazione della Terra rispetto alle stelle lontane anzich\u00e9 al sole. Un giorno siderale dura circa <strong>23 ore 56 minuti e 4 secondi<\/strong> \u2013 quasi quattro minuti meno di un giorno solare \u2013 quindi le stelle sorgono quattro minuti prima ogni notte. Gli astronomi usano il <strong>tempo siderale locale (LST)<\/strong> per puntare i telescopi: una stella \u00e8 alla massima altezza nel cielo quando l\u2019LST \u00e8 uguale alla sua ascensione retta.<\/p><p>La <strong>data giuliana<\/strong> \u00e8 un conteggio continuo dei giorni dal mezzogiorno UTC del 1\u00b0 gennaio 4713 a.C., usato in astronomia per evitare le complicazioni del calendario. La <strong>data giuliana modificata<\/strong> (MJD) \u00e8 JD \u2212 2.400.000,5 e inizia a mezzanotte.<\/p><\/div><\/section><section class=\"wc-section wc-faq\"><h2>Domande frequenti<\/h2><details><summary>Come si calcola il tempo siderale locale?<\/summary><p>Calcola il tempo siderale medio di Greenwich a partire dalla data giuliana, poi aggiungi la tua longitudine in ore (longitudine \u00f7 15, positiva verso est). Il calcolatore qui sopra lo fa in tempo reale per qualsiasi localit\u00e0.<\/p><\/details><\/section><section class=\"wc-section wc-tools-grid\"><div class=\"wc-section__head\"><h2>Altri strumenti gratuiti per l\u2019ora<\/h2><a href=\"https:\/\/www.worldclock.com\/it\/strumenti\/\">Tutti gli strumenti \u2192<\/a><\/div><div class=\"wc-toolcards\"><a class=\"wc-toolcard wc-toolcard--sun\" href=\"https:\/\/www.worldclock.com\/it\/alba-tramonto\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83c\udf05<\/span><span class=\"wc-toolcard__name\">Calcolatore di alba e tramonto<\/span><span class=\"wc-toolcard__desc\">Alba, tramonto e ora d\u2019oro.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--golden\" href=\"https:\/\/www.worldclock.com\/it\/calcolatore-golden-hour\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83d\udcf8<\/span><span class=\"wc-toolcard__name\">Calcolatore golden hour<\/span><span class=\"wc-toolcard__desc\">La luce migliore per le foto.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--moon\" href=\"https:\/\/www.worldclock.com\/it\/fase-lunare\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83c\udf15<\/span><span class=\"wc-toolcard__name\">Fase lunare di oggi<\/span><span class=\"wc-toolcard__desc\">La luna di stanotte e calendario lunare.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--fullmoon\" href=\"https:\/\/www.worldclock.com\/it\/calendario-lune-piene\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83c\udf1d<\/span><span class=\"wc-toolcard__name\">Calendario delle lune piene<\/span><span class=\"wc-toolcard__desc\">Date e nomi delle lune piene.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--moonrise\" href=\"https:\/\/www.worldclock.com\/it\/sorgere-tramonto-luna\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83c\udf19<\/span><span class=\"wc-toolcard__name\">Orari di sorgere e tramonto della luna<\/span><span class=\"wc-toolcard__desc\">Quando la luna sorge e tramonta.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--birthmoon\" href=\"https:\/\/www.worldclock.com\/it\/fase-lunare-compleanno\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83c\udf82<\/span><span class=\"wc-toolcard__name\">La luna del tuo compleanno<\/span><span class=\"wc-toolcard__desc\">La luna in qualsiasi data.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--astro\" href=\"https:\/\/www.worldclock.com\/it\/calendario-astronomico\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83d\udd2d<\/span><span class=\"wc-toolcard__name\">Calendario astronomico<\/span><span class=\"wc-toolcard__desc\">Eclissi, meteore ed eventi celesti.<\/span><\/a><a class=\"wc-toolcard wc-toolcard--converter\" href=\"https:\/\/www.worldclock.com\/it\/convertitore-fusi-orari\/\"><span class=\"wc-toolcard__icon\" aria-hidden=\"true\">\ud83d\udd01<\/span><span class=\"wc-toolcard__name\">Convertitore di fusi orari<\/span><span class=\"wc-toolcard__desc\">Converti un orario tra qualsiasi citt\u00e0.<\/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-29302","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\/it\/author\/clocker\/"},"comment_info":"","_links":{"self":[{"href":"https:\/\/www.worldclock.com\/it\/wp-json\/wp\/v2\/pages\/29302","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.worldclock.com\/it\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.worldclock.com\/it\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.worldclock.com\/it\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.worldclock.com\/it\/wp-json\/wp\/v2\/comments?post=29302"}],"version-history":[{"count":0,"href":"https:\/\/www.worldclock.com\/it\/wp-json\/wp\/v2\/pages\/29302\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.worldclock.com\/it\/wp-json\/wp\/v2\/media?parent=29302"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}