{"product_id":"pegasus-astro-2inch-mounted-photographic-filter-blue","title":"Pegasus Astro 2inch mounted photographic filter - Blue","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e2-inch mounted Blue (B) channel filter for LRGB astrophotography\u003c\/li\u003e\n\u003cli\u003eTransmission of \u0026gt;95% from 410nm to 500nm\u003c\/li\u003e\n\u003cli\u003eParfocal design to minimize refocusing when switching filters\u003c\/li\u003e\n\u003cli\u003e1\/4 wavefront polished optical glass for maximum image sharpness\u003c\/li\u003e\n\u003cli\u003eStandard M48x0.75 filter thread for 2-inch filter wheels and accessories\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003e2-inch Mounted Photographic Filter - Blue\u003c\/h2\u003e\n\u003cp\u003eThis 2-inch mounted photographic Blue filter isolates a critical portion of the visible spectrum with its 410-500nm bandpass, achieving greater than 95% average transmission for maximum signal. The optical glass is polished to a 1\/4 wavefront standard and housed in a 2-inch cell with standard M48x0.75 threads. Its parfocal design ensures that focus remains consistent when cycling through a complete LRGB filter set.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eA 410-500nm Bandpass with \u0026gt;95% Transmission\u003c\/h3\u003e\n\u003cp\u003eEngineered specifically for the blue channel in LRGB imaging, this filter's precise 410-500nm transmission window captures the light from reflection nebulae and the hot, young O- and B-type stars that illuminate them. With an average transmission rate exceeding 95% across this bandpass, your camera sensor receives maximum signal with minimal loss, shortening required exposure times. Multilayer anti-reflection coatings are applied to suppress halos and internal reflections, preserving the contrast between faint nebulosity and the dark sky background.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eParfocal Engineering in a 2-Inch M48 Cell\u003c\/h3\u003e\n\u003cp\u003eThis filter is designed to be parfocal, meaning you won't need to make significant focus adjustments when switching between it and other LRGB filters of the same series, saving valuable imaging time. The 2mm thick glass is housed in a standard 2-inch (M48x0.75 pitch) threaded cell, ensuring compatibility with virtually all 2-inch filter wheels and drawers. The filter's 1\/4 wavefront polish ensures it will not degrade the resolution of your optical system, maintaining sharp, point-like stars across the frame.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the primary use for this 2-inch Blue photographic filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis filter is designed as the Blue (B) component for LRGB (Luminance, Red, Green, Blue) deep-sky astrophotography. It isolates the 410-500nm wavelength range, which is crucial for capturing the natural color of star-forming regions, reflection nebulae like the Pleiades (M45), and the spiral arms of galaxies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill this 2-inch Blue filter fit my existing filter wheel?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. This filter uses the standard \u003cstrong\u003eM48x0.75 thread\u003c\/strong\u003e pitch, which is the industry standard for 2-inch mounted astronomical filters. It is compatible with virtually any 2-inch filter wheel, filter drawer, or accessory that accepts 2-inch filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does \"parfocal\" mean for this Blue filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eParfocal\u003c\/strong\u003e means the filter is manufactured to a specific thickness (2mm glass in this case) so that the focal point of your telescope does not shift significantly when you switch between it and other parfocal filters in a set (like Red and Green). This minimizes or eliminates the need to refocus your camera, streamlining your imaging sessions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the 1\/4 wavefront polish on this Blue filter affect my images of galaxies like Andromeda (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA \u003cstrong\u003e1\/4 wavefront\u003c\/strong\u003e polish ensures the filter's glass surface is extremely flat and will not distort the incoming light. For a target like the Andromeda Galaxy (M31), this translates to sharper star points within its spiral arms and a clearer definition of its dust lanes, preserving the fine detail resolved by your telescope's main optics.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is the \u0026gt;95% transmission important for this 2-inch Blue filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eHigh transmission means more light from your target reaches the camera sensor in less time. With \u003cstrong\u003e\u0026gt;95% average transmission\u003c\/strong\u003e in its 410-500nm bandpass, this filter allows you to capture a stronger signal for the blue channel with shorter sub-exposures, improving your overall signal-to-noise ratio and revealing fainter details.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use this Blue photographic filter for visual observing with an 8\" SCT?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile designed for photography, you can use it visually. However, as a bandpass filter, it will impart a strong blue tint to everything and significantly dim the view. It is not a color-correction or light pollution filter and is generally not recommended for visual use as it will not enhance detail on most objects in the way a nebula filter would.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Size\u003c\/td\u003e\n\u003ctd\u003e2 inch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical Polish\u003c\/td\u003e\n\u003ctd\u003e1\/4 wavefront, Parfocal\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Range\u003c\/td\u003e\n\u003ctd\u003e410-500nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePeak Transmission\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;95% (Average)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoatings\u003c\/td\u003e\n\u003ctd\u003eMultilayer Anti-reflection\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eBandpass (Blue Channel)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eShape\u003c\/td\u003e\n\u003ctd\u003eRound\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eGlass Thickness\u003c\/td\u003e\n\u003ctd\u003e2mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTotal Thickness\u003c\/td\u003e\n\u003ctd\u003e5mm (filter) + 2.5mm (thread)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thread\u003c\/td\u003e\n\u003ctd\u003eM48 x 0.75 pitch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003e2-inch Mounted Photographic Filter - Blue\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eProtective Case\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/davidastro.com\/pages\/pegasus-astro-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003ePegasus Astro 2-Year Warranty\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Pegasus Astro","offers":[{"title":"Default Title","offer_id":52686359724317,"sku":"PEG-FLTR-2M-B","price":84.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/pegasus-astro-2inch-mounted-photographic-filter-blue-1_2ec71649-2a2c-4505-a493-d8886116540b.png?v=1793650767","url":"https:\/\/davidastro.com\/en-us\/products\/pegasus-astro-2inch-mounted-photographic-filter-blue","provider":"David Astro","version":"1.0","type":"link"}