{"id":3862,"date":"2025-03-06T20:39:03","date_gmt":"2025-03-06T19:39:03","guid":{"rendered":"https:\/\/deep-space-astronomy.geekworkers.dev\/produit\/filtre-chroma-h-alpha-3nm-ultra\/"},"modified":"2025-06-03T10:40:49","modified_gmt":"2025-06-03T08:40:49","slug":"filtre-chroma-h-alpha-3nm-ultra","status":"publish","type":"product","link":"https:\/\/deep-space-astronomy.ch\/en\/product\/filtre-chroma-h-alpha-3nm-ultra\/","title":{"rendered":"Chroma H-alpha filter 3nm Ultra - 2\u2033 Mounted"},"content":{"rendered":"<h3>Chroma 3nm H-alpha filter<\/h3>\n<p>The filter <strong>H-alpha 3nm from Chroma<\/strong> is a very narrow-band filter designed for astronomical imaging, particularly suited to capturing nebulae rich in ionized hydrogen. With a bandwidth centered on the H-alpha line at 656.3 nm, it offers exceptional deep-sky performance, even under conditions of light pollution.<\/p>\n<h4>Key features<\/h4>\n<ul>\n<li><strong>Bandwidth :<\/strong> 3 nm, enabling precise isolation of the H-alpha line while suppressing unwanted wavelengths.<\/li>\n<li><strong>High transmission :<\/strong> Up to 90 % at 656.3 nm, guaranteeing an excellent signal-to-noise ratio.<\/li>\n<li><strong>Optical quality :<\/strong>\n<ul>\n<li>Surface polished to an accuracy of \u03bb\/4.<\/li>\n<li>Multilayer anti-reflective coating on both sides to prevent halos and stray reflections.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Available formats :<\/strong>\n<ul>\n<li>1.25\" (mounted)<\/li>\n<li>2\" (mounted)<\/li>\n<li>31 mm and 36 mm (unmounted)<\/li>\n<\/ul>\n<\/li>\n<li><strong>Substrate thickness :<\/strong> Approx. 2 mm.<\/li>\n<\/ul>\n<h4>Technical advantages<\/h4>\n<ul>\n<li><strong>Enhanced contrast :<\/strong>\n<ul>\n<li>Effectively eliminates stray lines, especially those from mercury vapor and sodium lamps.<\/li>\n<li>Significant reduction of sky background for maximum contrast.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Imaging under light pollution :<\/strong> Ideal for astrophotographers working in urban or suburban areas.<\/li>\n<li><strong>Compatibility with high-speed systems :<\/strong>\n<ul>\n<li>Optimized for focal ratios up to f\/4.0 or less.<\/li>\n<li>Available in a \"High-Speed\" version for very fast systems (f\/2.6 to f\/3.6), compensating for blueshift.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Various applications:<\/strong>\n<ul>\n<li>Imaging diffuse and planetary nebulae.<\/li>\n<li>Capturing supernova afterglow rich in ionized hydrogen.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h4>Prices and availability<\/h4>\n<ul>\n<li><strong>3nm H-alpha filter mounted in 2\" :<\/strong> Approx. \u20ac1,669, with a typical delivery time of 3 to 5 weeks.<\/li>\n<li><strong>Other formats available :<\/strong> Prices vary according to size and assembly.<\/li>\n<\/ul>\n<h4>Conclusion<\/h4>\n<p>The filter <strong>Chroma H-alpha 3nm<\/strong> is an essential tool for astrophotographers seeking to maximize contrast and image quality in deep-sky imaging. Its optical precision, high transmission and ability to handle light pollution make it a top-of-the-range choice for capturing the subtle details of nebulae rich in ionized hydrogen.<\/p>","protected":false},"excerpt":{"rendered":"<p>Filtre H-alpha 3nm de Chroma Le filtre H-alpha 3nm de Chroma est un filtre \u00e0 bande tr\u00e8s \u00e9troite con\u00e7u pour l\u2019imagerie astronomique, particuli\u00e8rement adapt\u00e9 \u00e0 la capture des n\u00e9buleuses riches en hydrog\u00e8ne ionis\u00e9. Avec une bande passante centr\u00e9e sur la raie H-alpha \u00e0 656,3 nm, il offre des performances exceptionnelles pour le ciel profond, m\u00eame [&hellip;]<\/p>\n","protected":false},"featured_media":3855,"comment_status":"open","ping_status":"closed","template":"","meta":[],"product_brand":[582],"product_cat":[780],"product_tag":[],"class_list":["post-3862","product","type-product","status-publish","has-post-thumbnail","product_brand-chroma","product_cat-filtres-bande-etroite","first","on_supplier","taxable","shipping-taxable","purchasable","product-type-simple"],"_links":{"self":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/product\/3862","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/comments?post=3862"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/media\/3855"}],"wp:attachment":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/media?parent=3862"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/product_brand?post=3862"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/product_cat?post=3862"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/product_tag?post=3862"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}