{"id":10,"date":"2012-12-27T18:00:49","date_gmt":"2012-12-27T18:00:49","guid":{"rendered":"http:\/\/www.boto.cz\/?p=10"},"modified":"2013-03-07T17:28:39","modified_gmt":"2013-03-07T17:28:39","slug":"jak-je-na-tom-tma-v-beskydech","status":"publish","type":"post","link":"http:\/\/www.boto.cz\/?p=10","title":{"rendered":"Jak je na tom tma v Beskydech?"},"content":{"rendered":"

O tom, \u017ee vznik\u00e1 Beskydsk\u00e1 oblast tmav\u00e9 oblohy, jsme ji\u017e informovali. Mo\u017en\u00e1 si ale \u0159eknete \u2013 v\u017edy\u0165 to nen\u00ed \u017e\u00e1dn\u00e1 nep\u0159\u00edstupn\u00e1 oblast a lidsk\u00e1 s\u00eddla jsou nedaleko. Jak je to tedy s beskydskou tmou ve skute\u010dnosti?<\/em><\/p>\n

<\/p>\n

Opravdov\u00e1 tma se nepozn\u00e1 jen podle toho, \u017ee vid\u00edte hodn\u011b hv\u011bzd a v\u00fdraznou Ml\u00e9\u010dnou dr\u00e1hu, ale tak\u00e9 d\u00edky dal\u0161\u00edm zaj\u00edmav\u00fdm \u00fakaz\u016fm. Mezi n\u011b pat\u0159\u00ed zodiak\u00e1ln\u00ed, nebo \u010desky zv\u00ed\u0159etn\u00edkov\u00e9 sv\u011btlo a d\u00e1le nap\u0159\u00edklad airglow nebo st\u00edny vrhan\u00e9 d\u00edky svitu planet a Ml\u00e9\u010dn\u00e9 dr\u00e1hy.<\/p>\n

\n

Zv\u00ed\u0159etn\u00edkov\u00e9 sv\u011btlo<\/strong><\/h3>\n

Je to p\u00e1s slab\u00e9ho sv\u011btla, kter\u00fd v ide\u00e1ln\u00edch podm\u00ednk\u00e1ch obep\u00edn\u00e1 celou oblohu. Na jeho spat\u0159en\u00ed je pot\u0159eba, aby byla obloha dostate\u010dn\u011b tmav\u00e1. Nejjasn\u011bj\u0161\u00ed \u010d\u00e1sti zv\u00ed\u0159etn\u00edkov\u00e9ho sv\u011btla jsou asi tak jasn\u00e9, jako slab\u0161\u00ed \u010d\u00e1sti Ml\u00e9\u010dn\u00e9 dr\u00e1hy. Zv\u00ed\u0159etn\u00edkov\u00e9 sv\u011btlo je vlastn\u011b Sluncem osv\u011btlen\u00fd meziplanet\u00e1rn\u00ed prach, kter\u00fd je koncentrov\u00e1n okolo roviny ekliptiky (neboli roviny, kde ob\u00edhaj\u00ed planety). Nejjasn\u011bj\u0161\u00ed je u obzoru nad r\u00e1nem, nebo ve\u010der. Na obloze lze pozorovat je\u0161t\u011b jedno zjasn\u011bn\u00ed v protislune\u010dn\u00edm bod\u011b, tzv. protisvit. Kdy\u017e je p\u00e1s zodiak\u00e1ln\u00edho sv\u011btla kompletn\u00ed (p\u0159es celou oblohu), potom mluv\u00edme o mostu. Kompletn\u00ed most v\u0161ak v Beskydech pozorovat nejde, na to je zde je\u0161t\u011b mal\u00e1 tma (kompletn\u00ed most doporu\u010dujeme pozorovat na Slovensku v Parku tmavej oblohy Poloniny, pop\u0159. jin\u00fdch tmav\u0161\u00edch lokalit\u00e1ch).<\/p>\n

Zv\u00ed\u0159etn\u00edkov\u00e9 sv\u011btlo je pozorovateln\u00e9 nejl\u00e9pe nad r\u00e1nem na podzim, nebo ve\u010der zjara, kdy sv\u00edr\u00e1 ekliptika dostate\u010dn\u00fd \u00fahel s obzorem. Tehdy p\u0159ipom\u00edn\u00e1 vysok\u00fd \u0161ikm\u00fd zu\u017euj\u00edc\u00ed se ku\u017eel sv\u011btla b\u011blav\u00e9 barvy. Protisvit vrchol\u00ed kolem p\u016flnoci a pozvolna se posouv\u00e1 souhv\u011bzd\u00edmi s t\u00edm, jak postupuje Slunce na druh\u00e9 stran\u011b nebesk\u00e9 sf\u00e9ry. Velikost tohoto sv\u011btlej\u0161\u00edho m\u00edsta na obloze je asi 5 a\u017e 10 stup\u0148\u016f a m\u00e1 trochu prot\u00e1hl\u00fd tvar ve sm\u011bru ekliptiky. Jak bylo \u0159e\u010deno, na velmi tmav\u00e9 obloze p\u0159ech\u00e1z\u00ed plynule v zodiak\u00e1ln\u00ed most (p\u00e1s).<\/p>\n

\"\"<\/a>
\nProtisvit – slab\u00e9, ov\u00e1ln\u00e9 zjasn\u011bn\u00ed na obloze, vpravo od st\u0159edu sn\u00edmku.<\/div>\n
\"\"<\/a>
\nKu\u017eel zodiak\u00e1ln\u00edho sv\u011btla<\/div>\n

<\/h3>\n

Airglow<\/strong><\/h3>\n

Dal\u0161\u00edm \u201ed\u016fkazem tmy\u201c je, kdy\u017e vid\u00edte sv\u00edtit vzduch. Ne, nen\u00ed to zp\u016fsobeno po\u017eit\u00edm halucinogenn\u00edch l\u00e1tek; vzduch skute\u010dn\u011b m\u016f\u017ee s\u00e1m z\u00e1\u0159it a \u0159\u00edk\u00e1 se tomu airglow. Princip je podobn\u00fd jako u vzniku pol\u00e1rn\u00ed z\u00e1\u0159e \u2013 elektron v atomu \u201evzduchu\u201c n\u00e1m vlivem n\u00e1razu nabit\u00e9 \u010d\u00e1stice posko\u010d\u00ed do vy\u0161\u0161\u00ed energetick\u00e9 hladiny a cestou na ni\u017e\u0161\u00ed hladinu se energie zbav\u00ed vyz\u00e1\u0159en\u00edm fotonu (sv\u011btla). U airglow je zdrojem do\u010dasn\u00e9ho zv\u00fd\u0161en\u00ed energie elektron\u016f v atomu sv\u011btlo, p\u0159esn\u011bji UV z\u00e1\u0159en\u00ed. Vzduch se p\u0159es den takto energeticky nasyt\u00ed a pr\u016fb\u011b\u017en\u011b pak energii vyza\u0159uje. My pak na fotografi\u00edch m\u016f\u017eeme vid\u011bt zelen\u00e9 p\u00e1sy z\u00e1\u0159\u00edc\u00edho vzduchu, nejl\u00e9pe nad obzorem, kdy je pozorujeme v\u00edce z boku. Ve sv\u011btlem zne\u010di\u0161t\u011bn\u00fdch oblastech je pr\u00e1v\u011b nejv\u00edce z\u00e1\u0159e u obzoru, a proto airglow \u010dasto zanik\u00e1. Pro pohled o\u010dima je pak airglow natolik slab\u00e9, \u017ee jej nelze pozorovat denn\u00edm barevn\u00fdm vid\u011bn\u00edm, proto re\u00e1ln\u011b budete m\u00edt pocit, \u017ee v n\u011bkter\u00e9m m\u00edst\u011b je obloha jaksi dif\u00fazn\u011b sv\u011btlej\u0161\u00ed. Fotografie v\u00e1m potom potvrd\u00ed zelenou barvu on\u00e9 tu\u0161en\u00e9 z\u00e1\u0159e.<\/p>\n

\"\"<\/a>
\nAirglow<\/div>\n

<\/h3>\n

St\u00edny<\/strong><\/h3>\n

Dal\u0161\u00edm \u201etemn\u00fdm\u201c \u00fakazem je pozorov\u00e1n\u00ed st\u00ednu, kter\u00fd vrhaj\u00ed p\u0159edm\u011bty osv\u011btlen\u00e9 jasn\u00fdm svitem planety Venu\u0161e. To jsme v\u0161ak letos na podzim nepozorovali, nemus\u00ed to v\u0161ak b\u00fdt zp\u016fsobeno \u201enedostatkem tmy\u201c, ale t\u0159eba ni\u017e\u0161\u00ed efektivn\u00ed z\u00e1\u0159\u00ed planety vlivem aktu\u00e1ln\u00edch podm\u00ednek. Za v\u00fdjime\u010dn\u00fdch podm\u00ednek, nap\u0159\u00edklad kdy\u017e m\u011bsta v okol\u00ed hor \u201ezalije\u201c siln\u00e1 vrstva n\u00edzk\u00e9 inverzn\u00ed obla\u010dnosti (utlum\u00ed sv\u011btlo m\u011bst), mohou se i na\u0161e nejtmav\u0161\u00ed horsk\u00e9 lokality p\u0159ibl\u00ed\u017eit na \u00farove\u0148, kdy za\u010d\u00edn\u00e1 sv\u00fdm svitem \u201evadit\u201c i Jupiter a objekty osv\u00edcen\u00e9 Ml\u00e9\u010dnou dr\u00e1hou vrhaj\u00ed st\u00edny. To u\u017e se ale sp\u00ed\u0161e bav\u00edme o lokalit\u00e1ch, kter\u00fdch je v Evrop\u011b velmi m\u00e1lo (op\u011bt zm\u00edn\u011bn\u00e9 Poloniny, p\u0159\u00edpadn\u011b vnitrozemsk\u00e1 poho\u0159\u00ed v\u00a0Chorvatsku, Alpy apod.).<\/p>\n

M\u011b\u0159en\u00ed jasu no\u010dn\u00ed oblohy<\/strong><\/h3>\n

Dal\u0161\u00ed mo\u017enost\u00ed, jak v\u011brohodn\u011b popsat tmu, je ji zm\u011b\u0159it. To se m\u016f\u017ee d\u011blat nap\u0159\u00edklad odhadem MHV (mezn\u00ed hv\u011bzdn\u00e1 velikost – hled\u00e1me nejslab\u0161\u00ed je\u0161t\u011b viditeln\u00e9 hv\u011bzdy) nebo m\u011b\u0159ic\u00edmi p\u0159\u00edstroji, nap\u0159\u00edklad SQM (Sky Quality Meter), p\u0159\u00edpadn\u011b popisem v\u00fdskytu sv\u011bteln\u00fdch \u201ekupol\u00ed\u201c m\u011bst a v\u00fd\u0161kou, do kter\u00e9 zasahuj\u00ed. N\u00e1\u0161 t\u00fdm provedl n\u011bkolik m\u011b\u0159en\u00ed v oblasti i jej\u00edm bl\u00edzk\u00e9m okol\u00ed a d\u00e1 se \u0159\u00edct, \u017ee jas oblohy v Beskydsk\u00e9 oblasti tmav\u00e9 oblohy dosahuje v pr\u016fm\u011bru 21,2 \u2013 21,3 MSA (magnituda na \u010dtvere\u010dn\u00ed \u00fahlovou vte\u0159inu oblohy). \u010c\u00edm vy\u0161\u0161\u00ed je \u010d\u00edslo, t\u00edm je obloha tmav\u0161\u00ed. Tabulku, kter\u00e1 v\u00e1m rychle objasn\u00ed v\u00fdznam \u010d\u00edseln\u00e9 hodnoty, najdete n\u00ed\u017ee. Veli\u010dina je logaritmick\u00e1, tak\u017ee obloha o 1 MSA tmav\u0161\u00ed je i okem z\u0159eteln\u011b temn\u011bj\u0161\u00ed. Mapu s nam\u011b\u0159en\u00fdmi hodnotami m\u016f\u017eete naj\u00edt na webu \u010desk\u00e9ho projektu mapov\u00e1n\u00ed sv\u011btlosti oblohy skyquality.com<\/a>. Nen\u00ed od v\u011bci tak\u00e9 zm\u00ednit, \u017ee na klimatologick\u00e9 stanici na B\u00edl\u00e9m k\u0159\u00ed\u017ei n\u00e1\u0161 t\u00fdm podpo\u0159en\u00fd z prost\u0159edk\u016f programu Think big Nadace O2 provozuje stanici na m\u011b\u0159en\u00ed jasu oblohy a pozorov\u00e1n\u00ed videometeor\u016f.<\/p>\n

\"\"<\/a>
\nP\u0159ibli\u017en\u00e9 hodnoty jasu no\u010dn\u00ed oblohy odpov\u00eddaj\u00ed v r\u016fzn\u00fdch lokalit\u00e1ch.<\/div>\n

<\/h3>\n

Geocaching<\/strong><\/h3>\n

Pr\u016fvodcem po tmav\u00fdch lokalit\u00e1ch v Beskydech, kde se d\u00e1 dob\u0159e pozorovat, s dobr\u00fdm dojezdem a m\u00edstem pro pozorov\u00e1n\u00ed (vyjma jedn\u00e9, kter\u00e1 v\u00e1s zavede do m\u00edst dopadu meteoritu Mor\u00e1vka), v\u00e1m m\u016f\u017ee b\u00fdt s\u00e9rie geocache s n\u00e1zvem Beskydsk\u00e1 oblast tmav\u00e9 oblohy, kter\u00e1 v sou\u010dasnosti vznik\u00e1. Na sv\u011bt\u011b u\u017e jsou prvn\u00ed t\u0159i geocache, dal\u0161\u00ed m\u016f\u017eete brzy o\u010dek\u00e1vat.<\/p>\n

\"\"<\/a>
\nNo\u010dn\u00ed odlov geocache<\/div>\n","protected":false},"excerpt":{"rendered":"

O tom, \u017ee vznik\u00e1 Beskydsk\u00e1 oblast tmav\u00e9 oblohy, jsme ji\u017e informovali. Mo\u017en\u00e1 si ale \u0159eknete \u2013 v\u017edy\u0165 to nen\u00ed \u017e\u00e1dn\u00e1 nep\u0159\u00edstupn\u00e1 oblast a lidsk\u00e1 s\u00eddla jsou nedaleko. Jak je to tedy s beskydskou tmou ve skute\u010dnosti?<\/p>\n","protected":false},"author":1,"featured_media":42,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0},"categories":[1],"tags":[],"_links":{"self":[{"href":"http:\/\/www.boto.cz\/index.php?rest_route=\/wp\/v2\/posts\/10"}],"collection":[{"href":"http:\/\/www.boto.cz\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.boto.cz\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.boto.cz\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.boto.cz\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=10"}],"version-history":[{"count":9,"href":"http:\/\/www.boto.cz\/index.php?rest_route=\/wp\/v2\/posts\/10\/revisions"}],"predecessor-version":[{"id":77,"href":"http:\/\/www.boto.cz\/index.php?rest_route=\/wp\/v2\/posts\/10\/revisions\/77"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.boto.cz\/index.php?rest_route=\/wp\/v2\/media\/42"}],"wp:attachment":[{"href":"http:\/\/www.boto.cz\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.boto.cz\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.boto.cz\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}