Astronomik City Light Suppression / Light Pollution Reduction CLS Filter - 1.25" Mounted
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The Astronomik CLS filter is designed for visual observation and photography of nebulae, galaxies, and star clusters using telescopes and lenses. It completely blocks the emission lines from high- and low-pressure sodium (Na) and mercury (Hg) vapor lamps, as well as all lines of natural airglow, while allowing the majority of visible light and nebulae emissions to pass through. This enhances the contrast between deep-sky objects and the night sky, making it ideal for photography and observation in light-polluted areas.
Due to its wide passband, the Astronomik CLS filter passes a substantial amount of light, minimally dimming stars. The filter is designed to block as much unwanted light as possible while still transmitting the maximum amount of light from astronomical objects.
Other uses
The 1.25" and 2" socket models can be used for observations from light-polluted areas.
Alternatives
If there is no built-in IR cut filter in your camera, an Astronomik CLS CCD filter is required.
Suitability of the Astronomik CLS filters
- CMOS and CCD photography: Good, requires an additional Astronomik IR-Block filter
- DSLR photography (original): Good, color balance is shifted but contrast is enhanced
- DSLR photography (astro-modified): Very good, color balance is close to perfect
- DSLR photography (MC-modified): Good, requires an additional Astronomik IR-Block filter
Size of filter
Astronomik filters come in a wide range of standard sizes, both mounted and unmounted, to suit various optical setups and cameras. This filter is a mounted filter in a threaded 1.25" cell (M28.5 x 0.6 thread).
Technical Data
- 92% transmission at 486nm (H-beta)
- 92% transmission at 496nm (OIII)
- 92% transmission at 501nm (OIII)
- 97% transmission at 656nm (H-alpha)
- Transmission range: 450nm to 540nm and above 650nm
- 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
- Parfocal with other Astronomik filters
- Diffraction-limited
- Optimized spectral windows
- Delivered in a high-quality, long-lasting filter box
Due 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.
Useful Resources
Filter Cell Specifications
D = Filter Cell Diameter = 31.2 mm / 1.23 in
T = Total Filter Height = 6.6 mm / 0.26 in
C = Filter Cell Height (Excluding Male Thread) = 4.5 mm / 0.18 in
M = Male Thread Length = 2.1 mm / 0.08 in
F = USABLE Female Filter Thread Length = Not threaded, so you cannot stack additional filters
S = Glass Substrate Thickness = 1 mm / 0.04 in
CA = Clear Aperture = 26.1 mm / 1.03 in
Other Information
- Country of Manufacture: Germany
The Astronomik CLS filter is designed for visual observation and photography of nebulae, galaxies, and star clusters using telescopes and lenses. It completely blocks the emission lines from high- and low-pressure sodium (Na) and mercury (Hg) vapor lamps, as well as all lines of natural airglow, while allowing the majority of visible light and nebulae emissions to pass through. This enhances the contrast between deep-sky objects and the night sky, making it ideal for photography and observation in light-polluted areas.
Due to its wide passband, the Astronomik CLS filter passes a substantial amount of light, minimally dimming stars. The filter is designed to block as much unwanted light as possible while still transmitting the maximum amount of light from astronomical objects.
Other uses
The 1.25" and 2" socket models can be used for observations from light-polluted areas.
Alternatives
If there is no built-in IR cut filter in your camera, an Astronomik CLS CCD filter is required.
Suitability of the Astronomik CLS filters
- CMOS and CCD photography: Good, requires an additional Astronomik IR-Block filter
- DSLR photography (original): Good, color balance is shifted but contrast is enhanced
- DSLR photography (astro-modified): Very good, color balance is close to perfect
- DSLR photography (MC-modified): Good, requires an additional Astronomik IR-Block filter
Size of filter
Astronomik filters come in a wide range of standard sizes, both mounted and unmounted, to suit various optical setups and cameras. This filter is a mounted filter in a threaded 1.25" cell (M28.5 x 0.6 thread).
Technical Data
- 92% transmission at 486nm (H-beta)
- 92% transmission at 496nm (OIII)
- 92% transmission at 501nm (OIII)
- 97% transmission at 656nm (H-alpha)
- Transmission range: 450nm to 540nm and above 650nm
- 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
- Parfocal with other Astronomik filters
- Diffraction-limited
- Optimized spectral windows
- Delivered in a high-quality, long-lasting filter box
Due 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.
The Astronomik CLS filter is designed for visual observation and photography of nebulae, galaxies, and star clusters using telescopes and lenses. It completely blocks the emission lines from high- and low-pressure sodium (Na) and mercury (Hg) vapor lamps, as well as all lines of natural airglow, while allowing the majority of visible light and nebulae emissions to pass through. This enhances the contrast between deep-sky objects and the night sky, making it ideal for photography and observation in light-polluted areas.
Due to its wide passband, the Astronomik CLS filter passes a substantial amount of light, minimally dimming stars. The filter is designed to block as much unwanted light as possible while still transmitting the maximum amount of light from astronomical objects.
Other uses
The 1.25" and 2" socket models can be used for observations from light-polluted areas.
Alternatives
If there is no built-in IR cut filter in your camera, an Astronomik CLS CCD filter is required.
Suitability of the Astronomik CLS filters
- CMOS and CCD photography: Good, requires an additional Astronomik IR-Block filter
- DSLR photography (original): Good, color balance is shifted but contrast is enhanced
- DSLR photography (astro-modified): Very good, color balance is close to perfect
- DSLR photography (MC-modified): Good, requires an additional Astronomik IR-Block filter
Size of filter
Astronomik filters come in a wide range of standard sizes, both mounted and unmounted, to suit various optical setups and cameras. This filter is a mounted filter in a threaded 1.25" cell (M28.5 x 0.6 thread).
Technical Data
- 92% transmission at 486nm (H-beta)
- 92% transmission at 496nm (OIII)
- 92% transmission at 501nm (OIII)
- 97% transmission at 656nm (H-alpha)
- Transmission range: 450nm to 540nm and above 650nm
- 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
- Parfocal with other Astronomik filters
- Diffraction-limited
- Optimized spectral windows
- Delivered in a high-quality, long-lasting filter box
Due 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.
Useful Resources
Filter Cell Specifications
D = Filter Cell Diameter = 31.2 mm / 1.23 in
T = Total Filter Height = 6.6 mm / 0.26 in
C = Filter Cell Height (Excluding Male Thread) = 4.5 mm / 0.18 in
M = Male Thread Length = 2.1 mm / 0.08 in
F = USABLE Female Filter Thread Length = Not threaded, so you cannot stack additional filters
S = Glass Substrate Thickness = 1 mm / 0.04 in
CA = Clear Aperture = 26.1 mm / 1.03 in
Other Information
- Country of Manufacture: Germany
Astronomik City Light Suppression / Light Pollution Reduction CLS Filter - 1.25" Mounted