NGC891 en L-RGB\u00a0<\/span><\/p><\/h2><\/span> Donn\u00e9es techniques Object : NGC891 Source wikipedia<\/p>\n NGC 891<\/b>\u00a0ou\u00a0Caldwell<\/a>\u00a023<\/b>\u00a0est une\u00a0galaxie spirale<\/a>\u00a0vue par la tranche et situ\u00e9e dans la\u00a0constellation d’Androm\u00e8de<\/a>. Sa vitesse par rapport au\u00a0fond diffus cosmologique<\/a>\u00a0est de\u00a0314<\/span>\u00a0\u00b1\u00a015<\/span>\u00a0km\/s<\/abbr>, ce qui correspond \u00e0 une\u00a0distance de Hubble<\/a>\u00a0de 4,63\u00a0\u00b1\u00a00,39\u00a0Mpc<\/a><\/abbr>\u00a0(\u223c15,1\u00a0millions d’al<\/a><\/abbr>)1<\/a><\/sup>. NGC 891 a \u00e9t\u00e9 d\u00e9couverte par l’astronome\u00a0germano<\/a>–britannique<\/a>\u00a0William Herschel<\/a>\u00a0en\u00a01784<\/a>.<\/p>\n NGC 891 a \u00e9t\u00e9 utilis\u00e9e par\u00a0G\u00e9rard de Vaucouleurs<\/a>\u00a0comme une galaxie de\u00a0type morphologique<\/a>\u00a0Sb sp dans son atlas des galaxies5<\/a><\/sup>,<\/sup>6<\/a><\/sup>.<\/p>\n La\u00a0classe de luminosit\u00e9<\/a>\u00a0de NGC 891 est II et elle pr\u00e9sente une large\u00a0raie HI<\/a>. Elle renferme \u00e9galement des\u00a0r\u00e9gions d’hydrog\u00e8ne ionis\u00e9<\/a>. C’est aussi une\u00a0galaxie active<\/a>\u00a0qui pr\u00e9sente un jet d’onde radio1<\/a><\/sup>.<\/p>\n La distance de Hubble de cette galaxie est \u00e9gale \u00e0 15,1 \u00b1 1,3 millions d’ann\u00e9es-lumi\u00e8re<\/a>. \u00c0 ce jour, une trentaine de mesures non bas\u00e9es sur le\u00a0d\u00e9calage vers le rouge<\/a>\u00a0(redshift<\/i>) donnent une distance de 9,535\u00a0\u00b1\u00a01,601\u00a0Mpc<\/a><\/abbr>\u00a0(\u223c31,1\u00a0millions d’al<\/a><\/abbr>)3<\/a><\/sup>. Cette distance est deux fois plus grande que la\u00a0distance de Hubble<\/a>, mais \u00e9tant donn\u00e9 la proximit\u00e9 de NGC 891 avec le\u00a0Groupe local<\/a>, cette valeur est sans doute plus pr\u00e8s de la distance r\u00e9elle de cette galaxie.<\/p>\n NGC 891 est le prototype m\u00eame des galaxies vues par la tranche, et le plan m\u00e9dian est ici travers\u00e9 par une \u00e9paisse bande de poussi\u00e8re qui semble fendre la galaxie en deux parties sym\u00e9triques. Malgr\u00e9 une\u00a0magnitude apparente<\/a>\u00a0de 10,1, la faible luminosit\u00e9 surfacique de cette galaxie, due au masquage du noyau galactique par la\u00a0bande d’absorption<\/a>, la rend relativement difficile \u00e0 observer. Elle se trouve, par effet de\u00a0perspective<\/a>, \u00e0 proximit\u00e9 imm\u00e9diate de l’amas de galaxies<\/a>\u00a0Abell 347<\/a>\u00a0mais n’en fait pas partie, cet amas se situant \u00e0 plus de 250 millions d’ann\u00e9es-lumi\u00e8re de notre Galaxie.<\/p>\n<\/div><\/div><\/div> Commentaires sur l’objet photographi\u00e9<\/span><\/p><\/h1><\/span>![](\"http:\/\/outters.fr\/wp-content\/uploads\/2024\/01\/ngc891-Lrgb6.jpg\")
<\/a><\/span><\/div><\/div><\/div>
\n<\/span><\/p><\/h2><\/span>Donn\u00e9es techniques de prise de vue<\/h2><\/div>
\nCommon name :
\nDate images Du 15 au 18 d\u00e9cembre2023
\nOptics : stl300
\nMount : Paramount ME Num\u00e9ro 3
\nLocation : Sirene observatory
\nSeeing : fwhm :
\nCcd : c3 moravian
\nfilter wheel : c3
\nfilters :\u00a0 Lrgb
\nFocuser :atlas
\nGuiding : Atik 314L+
\nTemp. out : T\u00b0
\nTemp ccd : -15\u00b0
\nTotal exposure : 12.30 h
\ntout en binning 1×1
\nRouge 45 x 2.5′ \/ vert 45 x 2.5′ \/ bleu 45 x 2.5′
\nL : 160 x 2.5′<\/p>\n<\/div><\/div><\/div>Donn\u00e9es scientifiques<\/h2><\/div>
Distance<\/span><\/h2>\n
Description<\/span><\/h2>\n
collaboration avec mon nouveau partenaire, Alexandre ITIC.<\/p>\n<\/p>\n<\/div><\/div><\/div><\/div><\/div><\/p>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":10432,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"image","meta":{"footnotes":""},"categories":[96,112,120,128,504,571,572],"tags":[370,621,622,625],"class_list":["post-10433","post","type-post","status-publish","format-image","has-post-thumbnail","hentry","category-galaxie","category-ngc","category-lrgb","category-observatoire-sirene","category-favorites","category-saison-2023","category-stl300-f4","tag-sirene","tag-outters","tag-itic","tag-ngc891","post_format-post-format-image"],"_links":{"self":[{"href":"https:\/\/www.outters.fr\/index.php?rest_route=\/wp\/v2\/posts\/10433","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.outters.fr\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.outters.fr\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.outters.fr\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.outters.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=10433"}],"version-history":[{"count":3,"href":"https:\/\/www.outters.fr\/index.php?rest_route=\/wp\/v2\/posts\/10433\/revisions"}],"predecessor-version":[{"id":10439,"href":"https:\/\/www.outters.fr\/index.php?rest_route=\/wp\/v2\/posts\/10433\/revisions\/10439"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.outters.fr\/index.php?rest_route=\/wp\/v2\/media\/10432"}],"wp:attachment":[{"href":"https:\/\/www.outters.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10433"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.outters.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10433"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.outters.fr\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10433"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}