{"id":5634,"date":"2020-08-19T16:04:56","date_gmt":"2020-08-19T14:04:56","guid":{"rendered":"http:\/\/www.arnaudom.fr\/wordpress\/?page_id=5634"},"modified":"2020-08-19T16:16:28","modified_gmt":"2020-08-19T14:16:28","slug":"reflexcon","status":"publish","type":"page","link":"https:\/\/www.arnaudom.fr\/wordpress\/reflexcon\/","title":{"rendered":"reflexcon"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-page\" data-elementor-id=\"5634\" class=\"elementor elementor-5634\">\n\t\t\t\t\t\t<div class=\"elementor-inner\">\n\t\t\t\t<div class=\"elementor-section-wrap\">\n\t\t\t\t\t\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-b2509ed elementor-section-full_width elementor-section-height-default elementor-section-height-default\" data-id=\"b2509ed\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t\t\t<div class=\"elementor-row\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-8e6f723\" data-id=\"8e6f723\" data-element_type=\"column\" data-settings=\"{&quot;background_background&quot;:&quot;classic&quot;}\">\n\t\t\t<div class=\"elementor-column-wrap elementor-element-populated\">\n\t\t\t\t\t\t\t<div class=\"elementor-widget-wrap\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-3473650 elementor-widget elementor-widget-heading\" data-id=\"3473650\" data-element_type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t<h1 class=\"elementor-heading-title elementor-size-default\">Images avec un reflex num\u00e9rique<\/h1>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-036cf9d elementor-widget elementor-widget-image\" data-id=\"036cf9d\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t<div class=\"elementor-image\">\n\t\t\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"204\" src=\"https:\/\/www.arnaudom.fr\/wordpress\/wp-content\/uploads\/2018\/08\/Canon350D.jpg\" class=\"attachment-large size-large wp-image-1057\" alt=\"\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-47c6777 elementor-widget elementor-widget-heading\" data-id=\"47c6777\" data-element_type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Contraintes rencontr\u00e9es avec mon mat\u00e9riel :<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-da0d9a1 elementor-widget elementor-widget-text-editor\" data-id=\"da0d9a1\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t<div class=\"elementor-text-editor elementor-clearfix\">\n\t\t\t\t<p style=\"text-align: left;\">Pour l&rsquo;instant, avec le mat\u00e9riel que j&rsquo;ai (voir rubrique <a href=\"http:\/\/www.arnaudom.fr\/wordpress\/reflexmat\/\">mat\u00e9riel utilis\u00e9<\/a>), je suis soumis \u00e0 deux contraintes principales : une contrainte \u00ab\u00a0optique\u00a0\u00bb due au F\/D 4 de mon t\u00e9l\u00e9scope, et une contrainte li\u00e9e \u00e0 la limitation du temps de pose.<\/p><ul><li style=\"text-align: left;\"><b><span class=\"gras\">Contrainte optique :<\/span><\/b><br \/>il faut savoir que sur un Newton, plus le rapport F\/D est bas, plus la formule optique engendre de \u00ab\u00a0coma\u00a0\u00bb, qui est en fait un probl\u00e8me optique qui se traduit par des \u00e9toiles d\u00e9form\u00e9es en bord de champ (ph\u00e9nom\u00e8ne bien visible en photo mais \u00e9galement en visuel au 200\/800, surtout avec des oculaires de mauvaise qualit\u00e9). Bref, on voit plein de mini com\u00e8tes dans le t\u00e9l\u00e9scope &#8230; Ce probl\u00e8me fait qu&rsquo;une grande partie de la photo est alt\u00e9r\u00e9e, ce qui est dommage au vu de la taille du champ qu&rsquo;on peut photographier avec le Canon 350 D au foyer du 200\/800.<br \/>Il y a une solution \u00e0 ce probl\u00e8me, c&rsquo;est l&rsquo;utilisation d&rsquo;un correcteur de champ qui permet de palier \u00e0 ce ph\u00e9nom\u00e8ne. Il existe deux correcteurs principaux sur le march\u00e9 : le MPCC de Baader et le Paracorr de T\u00e9l\u00e9vue. Le MPCC est deux fois moins cher que le Paracorr, cependant il semblerait qu&rsquo;il ne fonctionne pas de fa\u00e7on optimale en dessous d&rsquo;un F\/D de 4,5 (information obtenue aupr\u00e8s de certains revendeurs et surtout de certains astronomes amateurs ayant utilis\u00e9 les deux). Bref, je pense qu&rsquo;il me faudra investir dans un paracorr, mais pour cela je vais devoir attendre que mon compte en banque se remplume un peu <span class=\"milieu2\"> <img decoding=\"async\" src=\"http:\/\/arnaudom.fr\/Img\/smclin.gif\" alt=\"clin d'oeil\" \/><\/span> &#8230;<span style=\"color: #ff0000;\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-5640\" src=\"http:\/\/www.arnaudom.fr\/wordpress\/wp-content\/uploads\/2020\/08\/MPCC.jpg\" alt=\"\" width=\"240\" height=\"222\" \/><\/span><span style=\"color: #ff0000;\"> \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Baader MPCC<\/span><\/li><\/ul><p style=\"text-align: center;\"><span style=\"color: #ff0000;\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-1920\" src=\"http:\/\/www.arnaudom.fr\/wordpress\/wp-content\/uploads\/2019\/02\/Paracorr.jpg\" alt=\"\" width=\"224\" height=\"200\" \/>Paracorr Televue<\/span><\/p><ul><li><b><span class=\"gras\">Limitation du temps de pose li\u00e9e \u00e0 l&rsquo;appareil photo :<\/span><\/b><br \/>j&rsquo;utilise pour l&rsquo;instant le logiciel de l&rsquo;appareil-photo qui permet de contr\u00f4ler des s\u00e9ries de pose avec l&rsquo;ordinateur, cependant il ne permet pas de contr\u00f4ler le mode longue pose (mode \u00ab\u00a0Bulb\u00a0\u00bb) du Canon. Je ne peux donc effectuer que des poses de 30 secondes maximum. L\u00e0 aussi, un bricolage ou l&rsquo;achat d&rsquo;un petit accessoire permettant d&rsquo;effectuer des s\u00e9ries de poses de longue dur\u00e9e est n\u00e9cessaire.<\/li><\/ul><ul><li><b><span class=\"gras\">Limitation du temps de pose li\u00e9e \u00e0 la monture :<\/span><\/b><br \/>la monture Sky View Pro, motoris\u00e9e en AD, reste une monture bas de gamme, donc on ne peut sans doute esp\u00e9rer de sa part un temps de suivi correct au-del\u00e0 d&rsquo;un certain temps. A 30 s de pose, j&rsquo;ai quelques d\u00e9chets dus aux erreurs de suivi d\u00e9j\u00e0. D\u00e9s que je pourrais faire des poses plus longues, j&rsquo;essaierai de voir jusqu&rsquo;\u00e0 combien on peut raisonnablement monter. Il serait \u00e9tonnant qu&rsquo;on puisse aller au-del\u00e0 de 45 secondes, peut-\u00eatre une minute grand maximum.<br \/>Cela \u00e9tant dit, il me semble qu&rsquo;en encha\u00eenant des poses de 45 s, on doit pouvoir d\u00e9j\u00e0 obtenir des clich\u00e9s int\u00e9ressants du ciel profond. J&rsquo;esp\u00e8re tester tout cela dans un futur proche.<\/li><\/ul>\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Images avec un reflex num\u00e9rique Contraintes rencontr\u00e9es avec mon mat\u00e9riel : Pour l&rsquo;instant, avec le mat\u00e9riel que j&rsquo;ai (voir rubrique mat\u00e9riel utilis\u00e9), je suis soumis \u00e0 deux contraintes principales : une contrainte \u00ab\u00a0optique\u00a0\u00bb due au F\/D 4 de mon t\u00e9l\u00e9scope, et une contrainte li\u00e9e \u00e0 la limitation du temps de pose. Contrainte optique :il faut &hellip;<\/p>\n<p class=\"read-more\"> <a class=\"\" href=\"https:\/\/www.arnaudom.fr\/wordpress\/reflexcon\/\"> <span class=\"screen-reader-text\">reflexcon<\/span> Lire la suite\u00a0\u00bb<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"disabled","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"footnotes":""},"class_list":["post-5634","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.arnaudom.fr\/wordpress\/wp-json\/wp\/v2\/pages\/5634","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.arnaudom.fr\/wordpress\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.arnaudom.fr\/wordpress\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.arnaudom.fr\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.arnaudom.fr\/wordpress\/wp-json\/wp\/v2\/comments?post=5634"}],"version-history":[{"count":5,"href":"https:\/\/www.arnaudom.fr\/wordpress\/wp-json\/wp\/v2\/pages\/5634\/revisions"}],"predecessor-version":[{"id":5642,"href":"https:\/\/www.arnaudom.fr\/wordpress\/wp-json\/wp\/v2\/pages\/5634\/revisions\/5642"}],"wp:attachment":[{"href":"https:\/\/www.arnaudom.fr\/wordpress\/wp-json\/wp\/v2\/media?parent=5634"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}