{"product_id":"astronomik-oiii-visual-filter","title":"Astronomik OIII Visual Filter","description":"\u003ch2\u003eAstronomik OIII Visual Filter\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eFrom the start, the Astronomik OIII Visual Filter has been very specifically designed for the visual observation of gaseous and planetary nebulae. The extremely narrow pass band of the two OIII lines brings a substantial contrast gain to these lines even under best observation conditions. On faint super nova remnants and faint planetary nebulae the Astronomik OIIIfilter will often make the difference as to whether the object can bee seen or not!\u003c\/strong\u003e The optimal aperture ratio for the use of the filter is 1:3 to 1:15 with apertures of more than 6\" (150mm). Transmission losses and chromatic distortions, which arise with other filters, occur with Astronomik OIII filters only when extremely bright aperture ratios of 1:3 and more come into play. The Astronomik OIII filters thus can expand the view of dispersed objects, generally speaking, to the whole visual field of view of the eyepiece and are not limited to only the center of the eyepiece.\u003c\/p\u003e\n\u003ch4\u003eMain use\u003c\/h4\u003e\n\u003cp\u003eSince enough light must be available to make use of the OIII filter it is best to use this filter with apertures of more than 6\" (150mm). Smaller instruments do not gather enough light for meaningful and satisfying astronomical work. However, please note: Many experienced Deep Sky observers, with apertures of more than 10\" (250mm), prefer using the OIII filter instead of the more versatile UHC filter. Due to the high optical quality of the Astronomik OIII filter substrate you will see the same needle-sharp stars as you would from your regular telescope. [caption id=\"attachment_3936\" align=\"aligncenter\" width=\"592\"]\u003c\/p\u003e\n\u003ch4\u003eSuitability\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eVisual observation (dark skies): Very good, huge contrast enhancement at O III-emission nebulas\u003c\/li\u003e\n\u003cli\u003eVisual observation (urban skies): Very good, huge contrast enhancement at O III-emission nebulas\u003c\/li\u003e\n\u003cli\u003eFilm photography: It depends, very long exposure time\u003c\/li\u003e\n\u003cli\u003eCCD photography: Good, when used with an additional IR-block-filter\u003c\/li\u003e\n\u003cli\u003eDSLR photography (original): Very good, huge contrast enhancement at O III-emission nebulas\u003c\/li\u003e\n\u003cli\u003eDSLR photography (astro modified): Very good, huge contrast enhancement at O III-emission nebulas\u003c\/li\u003e\n\u003cli\u003eDSLR photography (MC modified): Good, when used with an additional IR-block-filter\u003c\/li\u003e\n\u003cli\u003eWebcam \/ Video (Planets): Unsuitable\u003c\/li\u003e\n\u003cli\u003eWebcam \/ Video (Deep Sky): Reasonable, if light pollution is a big problem and OIII Objects are beeing observed\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eTechnical Specification\u003c\/h3\u003e\n\u003cp\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0652\/6245\/2965\/files\/astronomik_oiii_trans_480x480.png?v=1687450098\"\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cspan style=\"color: #ff8000;\"\u003eThe major emission lines of artifical light pollution: | Hg 435,8nm | Hg 546,1nm | Hg 577,0nm | Hg 578,1nm | | Na 589,0nm | Na 589,6nm | Na 615,4nm | Na 616,1nm |\u003c\/span\u003e \u003c\/span\u003e\u003cspan\u003e\u003c\/span\u003e\u003cspan style=\"color: #20a652;\"\u003eThe major emission lines of nebulas: H-β 486,1nm | OIII 495,9nm | OIII 500,7nm | H-α 656,3nm\u003c\/span\u003e\u003c\/p\u003e\n\u003ch4\u003eHow to Read the Chart\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eThe \u003cb\u003ehorizontal axis\u003c\/b\u003e is the \u003cb\u003eWavelength in Nanometers\u003c\/b\u003e (nm). 400nm is deep blue, at 520nm the human eye senses green and at 600nm red. At 656nm is the famous “H-Alpha” emission line of hydrogen.\u003c\/li\u003e\n\u003cli\u003eThe \u003cb\u003etransmission in %\u003c\/b\u003e is plotted on the \u003cb\u003evertical axis\u003c\/b\u003e.\u003c\/li\u003e\n\u003cli\u003eThe red line shows the \u003cb\u003etransmission of the filter\u003c\/b\u003e.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eVisual filters\u003c\/b\u003e: The \u003cb\u003egrey\u003c\/b\u003e line in the background shows the relative sensitivity of the human eye at night. The maximum is at ~510nm and drops to longer and shorter wavelengths. You can easily see, that you can´t see anything of the H-alpha line at night (even if you can during daylight!) The sensitivity at 656nm is 0% at night!\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003ePhotographic filters\u003c\/b\u003e: The grey line in the background shows the sensitivity of a typical CCD sensor.\u003c\/li\u003e\n\u003cli\u003eThe most important \u003cb\u003eartifical emission\u003c\/b\u003e lines are shown in orange. The artifical light pollution is dominated by see mercury (Hg) and sodium (Na), which are used in nearly all streetlights.\u003c\/li\u003e\n\u003cli\u003eThe most important \u003cb\u003eemission lines from nebulas\u003c\/b\u003e are shown in green. The most important lines are from ionized Hydrogen (H-alpha and H-beta) and double ionized oxygen (OIII).\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eTechnical Data\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003etyp. 95% transmission at 496nm (OIII)\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003etyp. 95% transmission at 501nm (OIII)\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003eComplete blocking of all disturbing wavelength coverages\u003c\/li\u003e\n\u003cli\u003eThe ideal filter for telescopes 10 \" (25cm) and larger\u003c\/li\u003e\n\u003cli\u003eMain operational use: Planetary nebulas \u0026amp; super nova remnants\u003c\/li\u003e\n\u003cli\u003eNo moisture-sensitivity, no aging, and totally scratch-proof\u003c\/li\u003e\n\u003cli\u003eExcellent carrier material - substrate is optically polished. The optical performance (resolution \u0026amp; contrast) of your telescope is not reduced in any way by the filter.\u003c\/li\u003e\n\u003cli\u003eParfocal with other Astronomik filters\u003c\/li\u003e\n\u003cli\u003eGlass thickness: 1mm\u003c\/li\u003e\n\u003cli\u003eCompletely resistant against high humidity, scratches and aging effects\u003c\/li\u003e\n\u003cli\u003eDiffraction limited, the filter will not reduce the optical performance of your telescope!\u003c\/li\u003e\n\u003cli\u003eAstronomik filters are delivered in a high-quality, long lasting, filter box\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eIn the box\u003c\/h3\u003e\n\u003cp\u003eFilter and filter case\u003c\/p\u003e\n\u003ch3\u003eManual \u0026amp; Warranty\u003c\/h3\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/istronomyplus.com\/pages\/astronomik-warranty\" target=\"_blank\"\u003eAstronomik 10-Year Warranty\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"Astronomik","offers":[{"title":"1.25\" (M28.5)","offer_id":44116153204965,"sku":"AK-8h0006","price":135.0,"currency_code":"CAD","in_stock":true},{"title":"2\" (M48)","offer_id":44116153237733,"sku":"AK-8h0045","price":271.0,"currency_code":"CAD","in_stock":true},{"title":"SC Rear Cell (2'' \/ 24TPI)","offer_id":44116153270501,"sku":"AK-8h00bk","price":312.0,"currency_code":"CAD","in_stock":true},{"title":"T-Mount (M42 x 0.75)","offer_id":44127359631589,"sku":"AK-8h00bj","price":271.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0652\/6245\/2965\/files\/astronomik-oiii-visual-filter-astronomy-plus-1.jpg?v=1690483935","url":"https:\/\/istronomyplus.com\/products\/astronomik-oiii-visual-filter","provider":"Astronomy Plus – Telescopes \u0026 Astrophotography Canada","version":"1.0","type":"link"}