{"id":7730,"date":"2004-05-16T11:55:58","date_gmt":"2004-05-16T11:55:58","guid":{"rendered":"https:\/\/groupeastronomiespa.be\/astrogas\/m51-darks-et-flats-15-mai-2004\/"},"modified":"2025-06-21T12:05:36","modified_gmt":"2025-06-21T10:05:36","slug":"m51-darks-et-flats-15-mai-2004","status":"publish","type":"post","link":"https:\/\/groupeastronomiespa.be\/astrogas\/m51-darks-et-flats-15-mai-2004\/","title":{"rendered":"M51, darks et flats, 15 mai 2004"},"content":{"rendered":"

Le vent du nord a chass\u00e9 les nuages en cours de nuit, ce qui a permis de prendre enfin quelques images !
\nRevoici M51, qui \u00e9tait quasi au z\u00e9nith.<\/p>\n

15 images de 2 minutes, sans guidage, CCD SX MX916 en mode progessive. Celestron C9 focale 1500mm.
\nPris depuis mon jardin, proche de l’autoroute.
\nLa mise au point est imparfaite et la turbulence \u00e9tait assez forte.<\/p>\n

\"\"<\/a><\/p>\n

Manu ayant tr\u00e8s justement point\u00e9 la qualit\u00e9 du fond du ciel sur mes images en g\u00e9n\u00e9ral, j’ai, sur ses conseils, construit de mes deux mains gauches une bo\u00eete pour prendre de PLUs (aka flats), que j’ai inaugur\u00e9e hier soir… apr\u00e8s avoir nettoy\u00e9 tant bien que mal le train optique.<\/p>\n

All\u00e9luia !
\nLes 3 images (r\u00e9duites \u00e0 50 %) qui suivent montrent bien l’influence des darks et des flats:
\n1) images combin\u00e9es, sans dark ni flat; on voit bien les pixels chauds et le fond du ciel peu uniforme (vignettage + poussi\u00e8res etc…)<\/p>\n

\"\"<\/a><\/p>\n

2) idem, avec dark seul: les pixels chauds ont disparu, le fond du ciel est toujours m\u00e9diocre<\/p>\n

\"\"<\/a><\/p>\n

3) idem, avec dark et flat: la diff\u00e9rence est \u00e9vidente !
\nCela valait vraiment la peine, merci \u00e0 Manu d’avoir insist\u00e9 !<\/p>\n

\"\"<\/a><\/p>\n\n\n

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\n 10\/10 - (1 vote) <\/div>\n <\/div>\n","protected":false},"excerpt":{"rendered":"

Le vent du nord a chass\u00e9 les nuages en cours de nuit, ce qui a permis de prendre enfin quelques images ! Revoici M51, qui \u00e9tait quasi au z\u00e9nith. 15 images de 2 minutes, sans guidage, CCD SX MX916 en mode progessive. Celestron C9 focale 1500mm. Pris depuis mon jardin, proche de l’autoroute. La mise […]<\/p>\n","protected":false},"author":15,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[2],"tags":[],"class_list":["post-7730","post","type-post","status-publish","format-standard","hentry","category-astrophotos"],"_links":{"self":[{"href":"https:\/\/groupeastronomiespa.be\/astrogas\/wp-json\/wp\/v2\/posts\/7730","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/groupeastronomiespa.be\/astrogas\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/groupeastronomiespa.be\/astrogas\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/groupeastronomiespa.be\/astrogas\/wp-json\/wp\/v2\/users\/15"}],"replies":[{"embeddable":true,"href":"https:\/\/groupeastronomiespa.be\/astrogas\/wp-json\/wp\/v2\/comments?post=7730"}],"version-history":[{"count":3,"href":"https:\/\/groupeastronomiespa.be\/astrogas\/wp-json\/wp\/v2\/posts\/7730\/revisions"}],"predecessor-version":[{"id":15295,"href":"https:\/\/groupeastronomiespa.be\/astrogas\/wp-json\/wp\/v2\/posts\/7730\/revisions\/15295"}],"wp:attachment":[{"href":"https:\/\/groupeastronomiespa.be\/astrogas\/wp-json\/wp\/v2\/media?parent=7730"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/groupeastronomiespa.be\/astrogas\/wp-json\/wp\/v2\/categories?post=7730"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/groupeastronomiespa.be\/astrogas\/wp-json\/wp\/v2\/tags?post=7730"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}