{"product_id":"astrodon-e-series-gen-2-lrgb-filter-set-unmounted-49-7mm","title":"Astrodon E-Series Gen. 2 LRGB Filter set unmounted 49.7mm","description":"\u003cp\u003e\u003cstrong\u003eAstrodon\u003c\/strong\u003e  Generation 2 (Gen2) Tru-Balance RGB filters have revolutionized CCD imaging. Their popularity is due to their ease-of-use, high optical throughput and great resulting colors for galaxies, star clusters and nebulae.  There are two varieties of Tru-Balance filters- \u003cstrong\u003eE-Series\u003c\/strong\u003e and I-Series.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eE-Series\u003c\/strong\u003e filters are designed to approximately equalize the flux of red-sensitive \u003cstrong\u003efull-frame \u003c\/strong\u003e(\u003cstrong\u003eformerly Kodak \u003c\/strong\u003e\u003cstrong\u003eE-Series\u003c\/strong\u003e) CCD detectors, including compensation for the solar photon flux. This means that your RGB color combine weights will be approximately 1:1:1 within perhaps 10% for equal length exposures.  This can never be perfect, but it does allow you to take one exposure time for all of your RGB data and therefore, only just one corresponding dark exposure time.  Again, this saves you precious imaging time and thus, simplifies your imaging.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eFeatures:\u003c\/strong\u003e\u003cbr\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cul\u003e\n\n\u003cli\u003eSet includes Luminance (NIR\/UV-blocked colorless), Red, Green and Blue filters\u003c\/li\u003e\n\n\u003cli\u003e1.25\" mounted, 31, 36, 49.7 mm dia, 49.7 mm square (36 mm filters will not exceed 36.1 mm dia.)\u003c\/li\u003e\n\n\u003cli\u003e 3 +\/-0.025 mm single 1\/4-wave fused silica substrate before coating\u003c\/li\u003e\n\n\u003cli\u003e30 arcsec parallelism\u003c\/li\u003e\n\n\u003cli\u003e ~1:1:1 color combine weights for G2V white-point for Full-Frame (E) detectors\u003c\/li\u003e\n\n\u003cli\u003eBest choice for back-thinned and Sony detectors\u003c\/li\u003e\n\n\u003cli\u003eEqual RGB exposures and one dark time\u003c\/li\u003e\n\n\u003cli\u003eBetter color separation (see spectra)\u003c\/li\u003e\n\n\u003cli\u003eBetter color rendition for galaxies based upon color theory\u003c\/li\u003e\n\n\u003cli\u003eSignificant reflection and star halo reduction\u003c\/li\u003e\n\n\u003cli\u003eEnhanced contrast for HII regions in galaxies due to narrower red (not orange) filter\u003c\/li\u003e\n\n\u003cli\u003eSpectral \"gap\" between green and red filters to minimize effect of light pollution, especially from high pressure sodium street lamps (see spectra)\u003c\/li\u003e\n\n\u003cli\u003eHighest efficiency blue filter with less UV\u003c\/li\u003e\n\n\u003cli\u003eCorrect \"teal\" OIII color for planetary nebula (OIII signal \u0026gt;97% in blue and green)\u003c\/li\u003e\n\n\u003cli\u003eParfocal with \u003cstrong\u003eAstrodon\u003c\/strong\u003e's high-performance narrowband, Clear and Near-IR Luminance filters\u003c\/li\u003e\n\n\u003cli\u003eUltra-hard and durable sputtered coatings coated to the edge of each filter\u003c\/li\u003e\n\n\u003cli\u003e\u003cstrong\u003eProudly made in the U.S.A.\u003c\/strong\u003e\u003c\/li\u003e\n\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cbr\u003eThe \u003cstrong\u003eE-Series\u003c\/strong\u003e filters were designed for cameras containing the full-frame KAF8300, KAF3200, KAF6303, KAF16803 sensors. They are also a good choice for the latest Sony and back-thinned sensor.  The \u003cstrong\u003eE-Series\u003c\/strong\u003e red filter is a deep red filter about 60 nm wide, which excludes much of the light pollution from high pressure sodium street lamps. Other filter suppliers try to \"force fit\" their orange filter (designed for the interline KAI11000, KAI2000 sensors) for use with these full-frame sensors. Their orange filter (see below)  is about twice as wide spectrally as our deep red filter.  As a result, their orange filter tends to \"wash out\" HII regions in galaxies and detail in nebula. Their blue and green color weights are no longer balanced and as a result, the OIII color in planetary nebula is skewed strongly toward blue, rather than the correct teal color. These are the reasons why \u003cstrong\u003eAstrodon\u003c\/strong\u003e designed \u003cstrong\u003eE-\u003c\/strong\u003e and \u003cstrong\u003eI-Series\u003c\/strong\u003e \u003cstrong\u003efilters\u003c\/strong\u003e for these different classes of cameras for optimum results.\u003c\/p\u003e\n\n\u003cp\u003e \u003c\/p\u003e","brand":"ASTRODON","offers":[{"title":"Default Title","offer_id":46718144708780,"sku":"LRGB2_E50R","price":1188.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0602\/8073\/3868\/files\/41d73218-ac48-4054-9c9d-a1a4ede78b58.webp?v=1783110739","url":"https:\/\/landseaskyco.com\/products\/astrodon-e-series-gen-2-lrgb-filter-set-unmounted-49-7mm","provider":"Land Sea \u0026 Sky","version":"1.0","type":"link"}