Astronomik H-alpha 12 nm MaxFR XT Clip-Filter EOS XL (Astronomik, SKU: 10218220) is a narrowband filter for imaging hydrogen nebulae and HII regions in the H-alpha line. Selective transmission increases the contrast of the nebular signal by reducing unwanted background light at both dark and light-polluted sites. The Clip-Filter EOS XL version is designed to fit inside a compatible camera body.
• narrow 12 nm passband that increases nebula-to-background contrast
• blocking of unwanted out-of-band radiation, including UV and IR
• use with CMOS and CCD cameras to record a separate emission-line channel
• wider passband than 6 nm filters helps retain more guide stars
• the filter must not be used for solar observation
• installation and removal of the Clip-Filter without modifying the camera body or using additional tools
• thin substrate in the XT version to reduce edge aberrations with wide-angle lenses
• coatings: MaxFR, designed for fast optical systems; also usable with slower instruments
• optically polished glass and durable coatings resistant to scratches and humidity
• one Astronomik filter in the specified version, SKU: 10218220
• protective storage box
• manufacturer: Astronomik
• manufacturer SKU: 10218220
• filter type: H-alpha narrowband
• emission line: 656 nm
• full width at half maximum (FWHM): 12 nm
• guaranteed transmission for the H-alpha line at 656 nm: over 90%
• typical transmission for the H-alpha line at 656 nm: 96%
• out-of-band blocking: from UV to IR
• coatings: Astronomik MaxFR
• fast-optics range without significant transmission loss: f/1.7–f/6
• transmission relative to maximum at f/1.4: approximately 85%
• mounting: Clip-Filter EOS XL
• compatible Canon EOS cameras: 5D, 5D Mark II, 5D Mark III and 6D; the 5D does not offer Live View
• not compatible: EOS-1D in all versions, 5D Mark IV, 5DS, 5DS R and 6D Mark II
• slight corner vignetting may occur and can be corrected with flat frames
• storage: in the supplied box between sessions; the manufacturer advises against leaving the filter permanently inside the camera
• version: XT
• country of manufacture: Germany
The H-alpha filter records a selected component of nebular emission as a separate channel for further processing or a multiband composite.
