{"product_id":"antlia-solar-discover-dualband-erf","title":"Antlia Solar Discover Dualband ERF","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDualband design passes both H-alpha (656.3nm) and CaK\/CaH (393nm) wavelengths\u003c\/li\u003e\n\u003cli\u003eWide 25nm FWHM bandpass with over 90% peak transmission in both bands\u003c\/li\u003e\n\u003cli\u003eEnergy rejection filter (ERF) that blocks UV and IR light; coating range 200-1700nm\u003c\/li\u003e\n\u003cli\u003eLambda\/4 or better transmitted wavefront\u003c\/li\u003e\n\u003cli\u003e130mm, 150mm and 200mm versions in cells held in front of the telescope (fixed diameters 135-250mm), and a 2\" mounted version for the back end of refractors of 110mm or smaller\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\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\u003eAntlia Solar Discover Dualband ERF\u003c\/h2\u003e\n\u003cp\u003eThe Antlia Solar Discover Dualband ERF combines Hydrogen Alpha, Calcium K-Line and Calcium H-Line in one dualband filter, with H-alpha at 656.3nm and CaK\/CaH at 393nm and peak transmission above 90%. It is used together with the Antlia Solar Discover 3nm CaK, 5Å CaK or similar solar imaging equipment, protecting it from high temperature and bandpass shifting by rejecting heat before it enters the telescope. It blocks UV and IR light, has a coating range of 200-1700nm and a transmitted wavefront of Lambda\/4 or better. It cannot be used on its own.\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\u003eDual-Wavelength Access: 25nm Passbands at H-alpha and CaK\u003c\/h3\u003e\n\u003cp\u003eThe filter has two passbands. A 25nm FWHM band centered at 656.3nm passes the H-alpha line, and a second 25nm FWHM band centered at 393nm covers both the Calcium-K (393.3nm) and Calcium-H (396.8nm) lines. Each band has peak transmission above 90%, so one ERF serves solar imaging equipment working at either H-alpha or Calcium wavelengths.\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\u003eUV and IR Blocking with a 200-1700nm Coating Range\u003c\/h3\u003e\n\u003cp\u003eThe Antlia Dualband ERF is very effective at blocking UV and IR light while letting Ha 656.3nm, CaK 393.3nm and CaH 396.8nm pass through. Its coatings cover 200-1700nm. By rejecting heat before it enters the telescope, it protects your solar imaging equipment from high temperature and bandpass shifting.\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\u003eLambda\/4 Wavefront on a Heat-Resistant Quartz Substrate\u003c\/h3\u003e\n\u003cp\u003eThe Antlia Dualband ERF is coated on a heat-resistant, double-polished quartz glass substrate and finished with multi coatings. Its transmitted wavefront is Lambda\/4 or better. The 130mm, 150mm and 200mm filters are 10mm +\/-0.05mm thick, and the 2\" mounted filter is 3mm +\/-0.05mm thick.\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\u003eMounting: Front Cells and 2\" Mounted Version\u003c\/h3\u003e\n\u003cp\u003eThe 130mm, 150mm and 200mm versions are mounted in a housing\/cell that holds the filter in front of the telescope, for fixed diameters of 135-190mm, 165-220mm and 195-250mm respectively. The 2\" mounted version is installed on the back end of the \u003ca href=\"\/collections\/refractors\"\u003erefractor\u003c\/a\u003e and must be used on refractors of 110mm or smaller.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCritical Safety Note:\u003c\/strong\u003e This ERF is a component, not a complete \u003ca href=\"\/collections\/solar-filters\"\u003esolar filter\u003c\/a\u003e. It cannot be used on its own and \u003cstrong\u003emust\u003c\/strong\u003e be used together with professionally made solar imaging equipment that has its own complete blocking filters assembled, such as the Antlia Solar Discover 5Å CaK, Solar Discover 3nm CaK or Dualband Ha, CaK and CaH filter assemblies.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVisual Use Prohibited:\u003c\/strong\u003e Under no circumstances should this filter be used by itself for direct visual observation of the sun. It does not provide sufficient protection for the human eye.\u003c\/li\u003e\n\u003c\/ul\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 advantage of the Antlia Dualband ERF's dualband design?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003eAntlia Solar Discover Dualband ERF\u003c\/strong\u003e combines Hydrogen Alpha, Calcium K-Line and Calcium H-Line in one dualband filter: one passband for H-alpha (656.3nm) and another for Calcium K\/H (393nm), each 25nm FWHM with peak transmission above 90%. One ERF therefore serves solar imaging equipment at either wavelength.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Antlia Solar Discover Dualband ERF for visual solar observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eAbsolutely not.\u003c\/strong\u003e Do not use the Dualband ERF by itself for visual observation. It cannot be used on its own and must be used together with professionally made solar imaging equipment that has its own complete blocking filters assembled, such as the Antlia Solar Discover 5Å CaK, Solar Discover 3nm CaK or Dualband Ha, CaK and CaH filter assemblies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Antlia Dualband ERF protect my solar imaging equipment?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Antlia Dualband ERF rejects heat before it enters the telescope and is very effective at blocking UV and IR light. This protects your solar imaging equipment from high temperature and bandpass shifting.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhich Antlia Dualband ERF is for a refractor of 110mm aperture or smaller?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e2\" mounted Antlia Dualband ERF\u003c\/strong\u003e is installed on the back end of the refractor and must be used on refractors of 110mm or smaller. When you use a zenith mirror with an Antlia Solar Discover assembly, the ERF must be installed in the correct position shown in Antlia's installation diagram.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I choose the size of a front-mounted Antlia Dualband ERF?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eEach front-mounted version comes with a cell for a fixed diameter range: the \u003cstrong\u003e130mm\u003c\/strong\u003e for 135-190mm, the \u003cstrong\u003e150mm\u003c\/strong\u003e for 165-220mm and the \u003cstrong\u003e200mm\u003c\/strong\u003e for 195-250mm. The cell holds the filter in front of the telescope. Contact us if your telescope falls in two ranges.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy does the Antlia Dualband ERF have a wide 25nm bandpass?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe ERF's job is to reject heat before it enters the telescope, not to isolate the solar line. Its 25nm FWHM bands pass the H-alpha, CaK and CaH wavelengths with peak transmission above 90%. The final filtering is done by the solar imaging equipment it is used with, which has its own complete blocking filters, such as the Antlia Solar Discover assemblies.\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\u003eProduct Type\u003c\/td\u003e\n\u003ctd\u003eDualband solar energy rejection filter (ERF)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e2\" Mounted, 130mm, 150mm, 200mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-alpha Bandpass\u003c\/td\u003e\n\u003ctd\u003eCWL 656.3nm, FWHM 25nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCaK \u0026amp; CaH Bandpass\u003c\/td\u003e\n\u003ctd\u003eCWL 393nm (covers 393.3nm \u0026amp; 396.8nm), FWHM 25nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePeak Transmission\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;90% in both passbands\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating Range\u003c\/td\u003e\n\u003ctd\u003e200-1700nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront\u003c\/td\u003e\n\u003ctd\u003eLambda\/4 or better\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eHeat resistant, double-polished quartz glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness (130\/150\/200mm)\u003c\/td\u003e\n\u003ctd\u003e10mm +\/- 0.05mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness (2\" Mounted)\u003c\/td\u003e\n\u003ctd\u003e3mm +\/- 0.05mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e130mm Cell Fit\u003c\/td\u003e\n\u003ctd\u003eFor 135-190mm fixed diameter tubes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e150mm Cell Fit\u003c\/td\u003e\n\u003ctd\u003eFor 165-220mm fixed diameter tubes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e200mm Cell Fit\u003c\/td\u003e\n\u003ctd\u003eFor 195-250mm fixed diameter tubes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e2\" Mounted Max Aperture\u003c\/td\u003e\n\u003ctd\u003eFor refractors of 110mm or smaller\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRequired Equipment\u003c\/td\u003e\n\u003ctd\u003eCannot be used on its own; must be used with solar imaging equipment that has its own complete blocking filters\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVisual Use Safety\u003c\/td\u003e\n\u003ctd\u003eDo not use by itself for visual observation\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWarranty\u003c\/td\u003e\n\u003ctd\u003e3-Years\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\nAntlia 3-Year Warranty\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Antlia","offers":[{"title":"2\" Mounted","offer_id":51932625600797,"sku":"ANT-SD-ERF-2","price":139.0,"currency_code":"CAD","in_stock":true},{"title":"130mm","offer_id":51932625633565,"sku":"ANT-SD-ERF-130","price":1348.0,"currency_code":"CAD","in_stock":true},{"title":"150mm","offer_id":51932625666333,"sku":"ANT-SD-ERF-150","price":1756.0,"currency_code":"CAD","in_stock":true},{"title":"200mm","offer_id":51932625699101,"sku":"ANT-SD-ERF-200","price":3188.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/antlia-src-Yo7ImrKzDoBzjoBw_460f6d35-31b1-47e3-ad8a-9b246458c1cf.jpg?v=1792550012","url":"https:\/\/davidastro.com\/products\/antlia-solar-discover-dualband-erf","provider":"David Astro","version":"1.0","type":"link"}