Astronomik SII filter
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites.
The Astronomik SII filter significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background, allowing for long exposure times for deep and high-contrast images. For particularly high color-contrast results, the Astronomik SII filter is optimised to prevent H-alpha light from passing through.
The filter blocks the emission lines of high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, the maxima of typical LED lights, all lines of natural airglow, as well as most of the distracting moonlight.
The Astronomik SII filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).
Difference between Astronomik SII 4nm, 6nm and 12nm filters
The choice between 12nm, 6nm and 4nm Full-Width-Half-Maximum (FWHM) filters depends on your imaging conditions and camera type. There is no universal “best” option - each FWHM serves a specific purpose.
The 4nm Astronomik Narrowband-Emissionline filters are the best choice for astrophotography under extremely light-polluted skies. Astrophotographers who take pictures in a big city from their home garden or balcony can use the 4nm filters to create great, detailed, and high-contrast images of faint objects even under really bad skies. The 4nm Narrowband-Emissionline filters suppress stars even more than the 6nm filters. Compared to the 12nm filters, the number of stars is only about one third.
The 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way, as they typically halve the number of stars in the image compared to the 12nm filter. They are optimal if you are observing from a location with strong light pollution.
The 4nm and 6nm Astronomik Narrowband-Emissionline filters are recommended if you are using a CMOS astro camera or a modern system camera with very low dark current.
The 12nm Astronomik Narrowband-Emissionline filters are better suited for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current or if you are observing from suburban or dark-sky locations. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they show more guiding stars compared to the 4nm and 6nm filter.
In areas with little light pollution, the background signal in images is usually limited by the sensor’s dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the FWHM does not bring out more details in the object.
Difference between Astronomik MFR and MaxFR coating
Both the Astronomik MFR and MaxFR coatings offer extremely high contrast, minimized stray light, no halos and needle-sharp stars. In addition, they provide the best possible blocking across the entire spectral range from UV to IR.
The MFR filters can be used without any significant performance loss on the following instruments:
- 12nm MFR-coated filters: Instruments with aperture ratios from f/3 to f/15
- 6nm MFR-coated filters: Instruments with aperture ratios from f/4 to f/15
- 4nm MFR-coated filters: Instruments with aperture ratios from f/4.5 to f/15
The Astronomik MaxFR coating is specially designed for use with very fast optical systems.
Filters with MaxFR coating can be used without restriction on the following instruments:
- 12nm filters with MaxFR coating: Instruments with aperture ratios from f/1.7 to f/6 and approximately 15% reduced transmission at f/1.4
- 6nm filters with MaxFR coating: Instruments with aperture ratios from f/2.2 to f/6 and approximately 10% reduced transmission at f/2
- 4nm filters with MaxFR coating are currently in development.
- Filters for even faster optics are available on request.
Technical data
- Guaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)
- Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines
- Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)
- Finely polished optical glass, free of any striae, residual stresses, and bubbles
- Extremely scratch-resistant and durable coating
- Completely resistant against high humidity and aging effects
- Astronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)
- Parfocal with other Astronomik filters
- Diffraction-limited
- Optimized spectral windows
- Delivered in a high-quality, long-lasting filter box
- Made in Germany
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.

Astronomik SII 12nm 2" (M48)
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 6nm 2" (M48)
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 6nm 36mm
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 6nm 1,25" (M28,5)
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 12nm XT Clip-Filter EOS APS-C
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm or 6nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 12nm and 6nm filtersThe 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way, as they typically halve the number of stars in the image. They are also suitable if you have a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are better suited for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they generally provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.Filters for even faster optics are available on request.Difference between Astronomik standard and XT Clip-FiltersThe new Astronomik XT-Filters are specifically designed for astrophotography with wide-angle lenses, delivering sharp and crisp star images all the way to the edges of the image. When using very short focal length lenses to take widefield images, standard Clip-Filters could introduce aberrations, stretching stars in the outermost corners of the image. To solve this issue, the new Astronomik XT-Filters are coated on an extremely thin substrate of only 0.3mm or 0,5mm thickness, significantly reducing these aberrations. Despite the reduced thickness, the Astronomik XT-Filters maintain the highest optical quality. They are manufactured using the same durable coating technology as all Astronomik filters. More information about our XT-Filters can be found here.Technical dataGuaranteed transmission of more than 90% (12nm and 6nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 6nm 31mm
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 6nm 50mm
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 6nm 50 x 50mm², unmounted
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 12nm 1,25" (M28,5)
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 12nm Clip-Filter EOS R XL
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm or 6nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 12nm and 6nm filtersThe 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way, as they typically halve the number of stars in the image. They are also suitable if you have a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are better suited for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they generally provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.Filters for even faster optics are available on request.Difference between Astronomik standard and XT Clip-FiltersThe new Astronomik XT-Filters are specifically designed for astrophotography with wide-angle lenses, delivering sharp and crisp star images all the way to the edges of the image. When using very short focal length lenses to take widefield images, standard Clip-Filters could introduce aberrations, stretching stars in the outermost corners of the image. To solve this issue, the new Astronomik XT-Filters are coated on an extremely thin substrate of only 0.3mm or 0,5mm thickness, significantly reducing these aberrations. Despite the reduced thickness, the Astronomik XT-Filters maintain the highest optical quality. They are manufactured using the same durable coating technology as all Astronomik filters. More information about our XT-Filters can be found here.Technical dataGuaranteed transmission of more than 90% (12nm and 6nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 12nm Clip-Filter Nikon XL
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm or 6nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 12nm and 6nm filtersThe 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way, as they typically halve the number of stars in the image. They are also suitable if you have a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are better suited for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they generally provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.Filters for even faster optics are available on request.Difference between Astronomik standard and XT Clip-FiltersThe new Astronomik XT-Filters are specifically designed for astrophotography with wide-angle lenses, delivering sharp and crisp star images all the way to the edges of the image. When using very short focal length lenses to take widefield images, standard Clip-Filters could introduce aberrations, stretching stars in the outermost corners of the image. To solve this issue, the new Astronomik XT-Filters are coated on an extremely thin substrate of only 0.3mm or 0,5mm thickness, significantly reducing these aberrations. Despite the reduced thickness, the Astronomik XT-Filters maintain the highest optical quality. They are manufactured using the same durable coating technology as all Astronomik filters. More information about our XT-Filters can be found here.Technical dataGuaranteed transmission of more than 90% (12nm and 6nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 12nm 31mm
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 12nm 36mm
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 12nm 50mm
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 12nm 50 x 50mm², unmounted
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 6nm 27mm, unmounted
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 12nm 27mm, unmounted
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 6nm 42mm, unmounted
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 12nm 42mm, unmounted
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 6nm T-Mount (M42x0,75)
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 12nm T-Mount (M42x0,75)
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 12nm SC Rear Cell (2" / 24TPI)
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 6nm M49
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.

Astronomik SII 12nm M49
The Astronomik SII filter is ideal for imaging nebulae showing sulfur emissions from both light-polluted and dark observation sites. It significantly enhances the contrast between objects emitting light at 671.7nm and 673nm (SII lines) and the sky background. The Astronomik SII filter completely filters out the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, as well as all lines of natural airglow and most of the distracting moonlight.With a narrow bandwidth of either 12nm, 6nm or 4nm and high transmission rates, the filter effectively blocks all unwanted light from wavelengths other than 671.7nm and 673nm from ultraviolet (UV) to infrared (IR).In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the Full-Width-Half Maximum (FWHM) does not bring out more details in the object. Imaging with Astronomik Narrowband-Emissionline filtersImaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. Difference between Astronomik SII 4nm, 6nm and 12nm filters The 4nm and 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way. They are also recommended if you use a camera with very low dark current or if you are observing from a location with extreme light pollution.The 12nm Astronomik Narrowband-Emissionline filters are developed for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they provide more guiding stars.Difference between Astronomik MFR and MaxFR coatingBoth the Astronomik MFR and MaxFR coatings give you the best possible blocking across the entire spectral range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/∞ without significant performance loss.6nm MFR-coated filters can be used in all instruments with aperture ratios from f/4 to f/∞ without significant performance loss.4nm MFR-coated filters can be used in all instruments with aperture ratios from f/4.5 to f/15 without significant performance loss.The MaxFR coating is designed to work perfectly with fast optical systems. For 12nm filters with MaxFR coating, this means unlimited usability from f/1.7 to f/6 and approximately 85% of the maximum transmission at a f/1.4.For 6nm filters with MaxFR coating, this means unlimited usability from f/2.2 to f/6 and approximately 90% of the maximum transmission at a f/2.4nm filters with MaxFR coating are currently in development.Filters for even faster optics are available on request.Technical dataGuaranteed transmission of more than 90% (12nm, 6nm and 4nm) at both SII lines (671.7nm and 673.0nm)Typical transmission of 96% (12nm) and 93% (6nm and 4nm) at both SII lines Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)Finely polished optical glass, free of any striae, residual stresses, and bubblesExtremely scratch-resistant and durable coatingCompletely resistant against high humidity and aging effectsAstronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)Parfocal with other Astronomik filtersDiffraction-limitedOptimized spectral windowsDelivered in a high-quality, long-lasting filter boxDue to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore 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 coating is 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.




