Astronomik H-a MaxFR 4nm High-Speed Imaging Filter - 36mm Round Unmounted
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- Guaranteed transmission of more than 90% at H-alpha line (656nm)
- 36mm round unmounted filter with protective ring
- Astronomik MaxFR 4nm coatings
- Finely polished optical glass, with scratch-resistant coating
- Completely resistant against high humidity and aging effects
- Parfocal with other Astronomik filters
- Diffraction-Limited Optics & Optimized Spectral Windows
- Delivered in a high-quality, long-lasting filter box
Astronomik H-Alpha 4nm MaxFR - 36mm Unmounted
The Astronomik Hydrogen Alpha filter is ideal for imaging nebulae in both light-polluted and dark-sky sites. It significantly enhances the contrast between objects emitting light at 656nm (H-alpha line) and the sky background. The Astronomik H-a filter completely filters out the emission lines from high and low pressure sodium (Na), mercury (Hg) vapor lamps, natural airglow, and minimize distracting moonlight.
The 4nm filters are also the right tool for use with a CMOS astro camera or a modern system camera with very low dark current. They allow you to take very long exposures with minimal background noise. Please note: this H-alpha filter MUST NOT BE USED for solar observation.
Ultra-Narrow 4nm Bandpass
The Astronomik H-alpha 4nm filter delivers exceptional contrast by isolating H-a emissions at 656nm while blocking unwanted light pollution and moonlight. Its ultra-narrow 4nm bandpass reduces background glow and suppresses distracting stars, making it ideal for capturing faint nebulae in heavily light-polluted skies. With up to 93% typical transmission at 656nm, it preserves valuable H-a detail for sharp, high-contrast astrophotography.
Choosing the Right Bandpass & Coating
Astronomik Narrowband Emission Line Filters are available in 4nm, 6nm, and 12nm bandpasses to suit different imaging conditions and camera systems. Both MFR and MaxFR coatings deliver excellent light blocking, high contrast, minimal halos, and sharp stars.
-
4nm & 6nm Filters: Ideal for faint nebulae in star-rich regions, extreme light pollution, and cameras with very low dark current.
-
12nm Filters: Best suited for typical DSLR, CMOS, and CCD cameras with higher dark current, or systems requiring more guide stars.
-
MFR Coating: Designed for standard optical systems, supporting 12nm filters at f/3–f/∞, 6nm at f/4–f/∞, and 4nm at f/4.5–f/15.
-
MaxFR Coating: Optimized for fast optics, supporting 12nm filters at f/1.7–f/6 and 6nm filters at f/2.2–f/6 with minimal transmission loss. Even faster systems can be supported with some transmission loss. For 4nm filters with MaxFR coating, this means unlimited usability from f/2.8 to f/8.
Imaging with Astronomik Narrowband
Specifications
- Filter Size: 36mm Round Unmounted with Protective Ring
- Guaranteed Transmission: >90% at H-alpha (656nm)
- Typical Transmission: 93% at H-alpha (656nm)
- Full-Width-Half Maximum (FWHM): 4nm
- Glass thickness: 1mm
- Mechanical Thickness: 3mm
Other Important Information
- Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Thanks to the high-precision machining of the glas substrate, all Astronomik filters are parfocal. The wedge errors are far below all common tolerances. Therefore, all issues concerning focal distances and the exact alignment of images from each color channel are effectively eliminated.
- All Astronomik filters are ideal for modern cameras, including both CMOS- and CCD-based models, ensuring you capture the best possible images with your equipment. Sharpness, contrast, and the absence of any reflections and halos are guaranteed. Even with bright stars in the field of view, nebulae and galaxies will be captured with the finest structures. The Astronomik MFR and MaxFR coatings are designed for optimal performance across a wide range of focal ratios of the optics used.
- Every Astronomik filter undergoes a rigorous quality control process before delivery. Additionally, each Astronomik Narrowband-Emissionline filter is measured using a high-end PerkinElmer Spectrophotometer to ensure it meets the specifications published on our website. On the back of each Narrowband-Emissionline filter box, you will find a label detailing the precise spectral data for that specific filter, including the maximum transmission and the recommended range of focal ratios for best performance of that specific filter.
Other Information
- Country of Manufacture: Germany
Astronomik H-Alpha 4nm MaxFR - 36mm Unmounted
The Astronomik Hydrogen Alpha filter is ideal for imaging nebulae in both light-polluted and dark-sky sites. It significantly enhances the contrast between objects emitting light at 656nm (H-alpha line) and the sky background. The Astronomik H-a filter completely filters out the emission lines from high and low pressure sodium (Na), mercury (Hg) vapor lamps, natural airglow, and minimize distracting moonlight.
The 4nm filters are also the right tool for use with a CMOS astro camera or a modern system camera with very low dark current. They allow you to take very long exposures with minimal background noise. Please note: this H-alpha filter MUST NOT BE USED for solar observation.
Ultra-Narrow 4nm Bandpass
The Astronomik H-alpha 4nm filter delivers exceptional contrast by isolating H-a emissions at 656nm while blocking unwanted light pollution and moonlight. Its ultra-narrow 4nm bandpass reduces background glow and suppresses distracting stars, making it ideal for capturing faint nebulae in heavily light-polluted skies. With up to 93% typical transmission at 656nm, it preserves valuable H-a detail for sharp, high-contrast astrophotography.
Choosing the Right Bandpass & Coating
Astronomik Narrowband Emission Line Filters are available in 4nm, 6nm, and 12nm bandpasses to suit different imaging conditions and camera systems. Both MFR and MaxFR coatings deliver excellent light blocking, high contrast, minimal halos, and sharp stars.
-
4nm & 6nm Filters: Ideal for faint nebulae in star-rich regions, extreme light pollution, and cameras with very low dark current.
-
12nm Filters: Best suited for typical DSLR, CMOS, and CCD cameras with higher dark current, or systems requiring more guide stars.
-
MFR Coating: Designed for standard optical systems, supporting 12nm filters at f/3–f/∞, 6nm at f/4–f/∞, and 4nm at f/4.5–f/15.
-
MaxFR Coating: Optimized for fast optics, supporting 12nm filters at f/1.7–f/6 and 6nm filters at f/2.2–f/6 with minimal transmission loss. Even faster systems can be supported with some transmission loss. For 4nm filters with MaxFR coating, this means unlimited usability from f/2.8 to f/8.
Imaging with Astronomik Narrowband
Specifications
- Filter Size: 36mm Round Unmounted with Protective Ring
- Guaranteed Transmission: >90% at H-alpha (656nm)
- Typical Transmission: 93% at H-alpha (656nm)
- Full-Width-Half Maximum (FWHM): 4nm
- Glass thickness: 1mm
- Mechanical Thickness: 3mm
Other Important Information
- Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Thanks to the high-precision machining of the glas substrate, all Astronomik filters are parfocal. The wedge errors are far below all common tolerances. Therefore, all issues concerning focal distances and the exact alignment of images from each color channel are effectively eliminated.
- All Astronomik filters are ideal for modern cameras, including both CMOS- and CCD-based models, ensuring you capture the best possible images with your equipment. Sharpness, contrast, and the absence of any reflections and halos are guaranteed. Even with bright stars in the field of view, nebulae and galaxies will be captured with the finest structures. The Astronomik MFR and MaxFR coatings are designed for optimal performance across a wide range of focal ratios of the optics used.
- Every Astronomik filter undergoes a rigorous quality control process before delivery. Additionally, each Astronomik Narrowband-Emissionline filter is measured using a high-end PerkinElmer Spectrophotometer to ensure it meets the specifications published on our website. On the back of each Narrowband-Emissionline filter box, you will find a label detailing the precise spectral data for that specific filter, including the maximum transmission and the recommended range of focal ratios for best performance of that specific filter.
- 1x H-a Filter - 36mm Unmounted
- 1x Protective Storage Box
- Guaranteed transmission of more than 90% at H-alpha line (656nm)
- 36mm round unmounted filter with protective ring
- Astronomik MaxFR 4nm coatings
- Finely polished optical glass, with scratch-resistant coating
- Completely resistant against high humidity and aging effects
- Parfocal with other Astronomik filters
- Diffraction-Limited Optics & Optimized Spectral Windows
- Delivered in a high-quality, long-lasting filter box
Astronomik H-Alpha 4nm MaxFR - 36mm Unmounted
The Astronomik Hydrogen Alpha filter is ideal for imaging nebulae in both light-polluted and dark-sky sites. It significantly enhances the contrast between objects emitting light at 656nm (H-alpha line) and the sky background. The Astronomik H-a filter completely filters out the emission lines from high and low pressure sodium (Na), mercury (Hg) vapor lamps, natural airglow, and minimize distracting moonlight.
The 4nm filters are also the right tool for use with a CMOS astro camera or a modern system camera with very low dark current. They allow you to take very long exposures with minimal background noise. Please note: this H-alpha filter MUST NOT BE USED for solar observation.
Ultra-Narrow 4nm Bandpass
The Astronomik H-alpha 4nm filter delivers exceptional contrast by isolating H-a emissions at 656nm while blocking unwanted light pollution and moonlight. Its ultra-narrow 4nm bandpass reduces background glow and suppresses distracting stars, making it ideal for capturing faint nebulae in heavily light-polluted skies. With up to 93% typical transmission at 656nm, it preserves valuable H-a detail for sharp, high-contrast astrophotography.
Choosing the Right Bandpass & Coating
Astronomik Narrowband Emission Line Filters are available in 4nm, 6nm, and 12nm bandpasses to suit different imaging conditions and camera systems. Both MFR and MaxFR coatings deliver excellent light blocking, high contrast, minimal halos, and sharp stars.
-
4nm & 6nm Filters: Ideal for faint nebulae in star-rich regions, extreme light pollution, and cameras with very low dark current.
-
12nm Filters: Best suited for typical DSLR, CMOS, and CCD cameras with higher dark current, or systems requiring more guide stars.
-
MFR Coating: Designed for standard optical systems, supporting 12nm filters at f/3–f/∞, 6nm at f/4–f/∞, and 4nm at f/4.5–f/15.
-
MaxFR Coating: Optimized for fast optics, supporting 12nm filters at f/1.7–f/6 and 6nm filters at f/2.2–f/6 with minimal transmission loss. Even faster systems can be supported with some transmission loss. For 4nm filters with MaxFR coating, this means unlimited usability from f/2.8 to f/8.
Imaging with Astronomik Narrowband
Specifications
- Filter Size: 36mm Round Unmounted with Protective Ring
- Guaranteed Transmission: >90% at H-alpha (656nm)
- Typical Transmission: 93% at H-alpha (656nm)
- Full-Width-Half Maximum (FWHM): 4nm
- Glass thickness: 1mm
- Mechanical Thickness: 3mm
Other Important Information
- Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Thanks to the high-precision machining of the glas substrate, all Astronomik filters are parfocal. The wedge errors are far below all common tolerances. Therefore, all issues concerning focal distances and the exact alignment of images from each color channel are effectively eliminated.
- All Astronomik filters are ideal for modern cameras, including both CMOS- and CCD-based models, ensuring you capture the best possible images with your equipment. Sharpness, contrast, and the absence of any reflections and halos are guaranteed. Even with bright stars in the field of view, nebulae and galaxies will be captured with the finest structures. The Astronomik MFR and MaxFR coatings are designed for optimal performance across a wide range of focal ratios of the optics used.
- Every Astronomik filter undergoes a rigorous quality control process before delivery. Additionally, each Astronomik Narrowband-Emissionline filter is measured using a high-end PerkinElmer Spectrophotometer to ensure it meets the specifications published on our website. On the back of each Narrowband-Emissionline filter box, you will find a label detailing the precise spectral data for that specific filter, including the maximum transmission and the recommended range of focal ratios for best performance of that specific filter.
Other Information
- Country of Manufacture: Germany
- 1x H-a Filter - 36mm Unmounted
- 1x Protective Storage Box