Under a clear sky, the faint parts of a nebula quickly disappear into the background glow. The Askar C2 filter from the Colour Magic series only allows through two narrow pieces of the spectrum: the emission line of doubly ionized oxygen (OIII) and that of sulfur (SII). Street lighting and sky glow are largely blocked out.<\/p>\n\n\n\n
A duo band filter is often used with a color camera, because you can capture two emission lines in one shot. It is a 2 inch filter, so it fits in a filter wheel for 2 inch filters<\/a> or a filter tray that fits that size.<\/p>\n\n\n\n Combined with an H-alpha image, you can build a full narrowband image. Check beforehand that your filter holder or filter wheel actually accepts 2-inch filters, because not every holder does that. This filter is intended for the night sky and not for the sun.<\/p>\n\n\n\n For the H-alpha side, there is the D1 filter for H-alpha and OIII<\/a>. You can find more filters for a clear sky at filters against light pollution<\/a>.<\/p>","protected":false},"excerpt":{"rendered":" 2-inch dual-band filter that passes the light of oxygen (OIII) and sulfur (SII). Allows nebulas to emerge from a light sky background.<\/p>","protected":false},"featured_media":112744,"comment_status":"open","ping_status":"closed","template":"","meta":{"_acf_changed":false},"product_brand":[1542],"product_cat":[588,3138,56],"product_tag":[],"class_list":["post-112745","product","type-product","status-publish","has-post-thumbnail","product_brand-askar","product_cat-filters","product_cat-imaging-filters-smalband-en-lrgb","product_cat-telescoop-accessoires","first","instock","taxable","shipping-taxable","purchasable","product-type-simple"],"bundled_by":[],"bundle_stock_status":"instock","bundle_stock_quantity":null,"bundle_virtual":false,"bundle_layout":"","bundle_add_to_cart_form_location":"","bundle_editable_in_cart":false,"bundle_sold_individually_context":"","bundle_item_grouping":"","bundle_min_size":"","bundle_max_size":"","bundle_price":[],"bundled_items":[],"bundle_sell_ids":[],"acf":[],"jetpack_sharing_enabled":true,"jetpack-related-posts":[{"id":112748,"url":"https:\/\/www.telescoop.nl\/en\/askar-color-magic-d1-oiii-h-alpha-duo-band-nevelfilter-2-inch-voor-kleurencameras\/","url_meta":{"origin":112745,"position":0},"title":"Askar Color Magic D1 OIII\/H-alpha duo-band night filter 2 inch for color cameras","author":"Info telescoop","date":"09-10-2026","format":false,"excerpt":"2-inch dual band filter for H-alpha and OIII. This allows you to capture the two main lines of emission nebulae in one shot with a color camera.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/77781_1.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/77781_1.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/77781_1.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":112769,"url":"https:\/\/www.telescoop.nl\/en\/askar-colour-magic-filterset-h-alpha-sii-en-oiii-3-nm-2-inch-voor-het-hubble-palet\/","url_meta":{"origin":112745,"position":1},"title":"Askar Colour Magic filterset H-alpha, SII and OIII 3 nm 2 inch for the Hubble palette","author":"Info telescoop","date":"09-10-2026","format":false,"excerpt":"Three narrow-band filters of 3 nm in 2 inches: H-alpha, SII and OIII. With these, you can build color images of nebulae in the Hubble palette using a monochrome camera.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87817_1.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87817_1.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87817_1.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":112758,"url":"https:\/\/www.telescoop.nl\/en\/askar-color-magic-d2-oiii-sii-duo-band-filter-2-inch-voor-nevelfotografie\/","url_meta":{"origin":112745,"position":2},"title":"Askar Color Magic D2 OIII\/SII duo-band filter 2 inch for night photography","author":"Info telescoop","date":"09-10-2026","format":false,"excerpt":"2-inch dual band filter for oxygen (OIII) and sulfur (SII) lines. A complement to an H-alpha\/OIII filter for neofoto photography.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87298_1.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87298_1.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87298_1.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":112767,"url":"https:\/\/www.telescoop.nl\/en\/askar-colour-magic-oiii-smalbandfilter-3-nm-2-inch-voor-nevelfotografie\/","url_meta":{"origin":112745,"position":3},"title":"Askar Colour Magic OIII narrow band filter 3 nm 2 inch for night photography","author":"Info telescoop","date":"09-10-2026","format":false,"excerpt":"3 nm narrowband filter for the OIII line of oxygen, in 2 inches. Reveals planetary nebulae and supernova remnants, even under light pollution.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87816_1.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87816_1.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87816_1.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":112764,"url":"https:\/\/www.telescoop.nl\/en\/askar-colour-magic-sii-smalbandfilter-3-nm-2-inch-voor-nevelfotografie\/","url_meta":{"origin":112745,"position":4},"title":"Askar Colour Magic SII narrowband filter 3 nm 2 inch for night photography","author":"Info telescoop","date":"09-10-2026","format":false,"excerpt":"3 nm narrowband filter for the SII line of sulfur, in 2 inches. Together with H-alpha and OIII, it forms the basis for nebula images in the Hubble palette.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87815_1.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87815_1.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87815_1.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":112761,"url":"https:\/\/www.telescoop.nl\/en\/askar-colour-magic-h-alpha-smalbandfilter-3-nm-2-inch-voor-nevelfotografie\/","url_meta":{"origin":112745,"position":5},"title":"Askar Colour Magic H-alpha narrowband filter 3 nm 2 inch for night photography","author":"Info telescoop","date":"09-10-2026","format":false,"excerpt":"3 nm narrowband filter for the red H-alpha line of hydrogen, in 2 inches. For night photography with a monochrome camera, even in low light conditions.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87814_1.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87814_1.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87814_1.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]}],"_links":{"self":[{"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product\/112745","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/comments?post=112745"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/media\/112744"}],"wp:attachment":[{"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/media?parent=112745"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product_brand?post=112745"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product_cat?post=112745"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product_tag?post=112745"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}