Optolong L-Ultimate Dual Bandpass Light Pollution Reduction Imaging Filter - 2"
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- Restricts transmission down to 3nm for H-Alpha and OIII, blocking out urban skyglow for enhanced nebula contrast
- Features upgraded internal coatings engineered to eliminate distracting, bloated halos around bright target stars
- Delivers a boost to your signal-to-noise ratio by wiping out city glare and artificial light, leaving clean data that is easy to process.
Optolong L-Ultimate: Fight Back Against Light Pollution!
The Optolong L-Ultimate is a professional-grade dual-bandpass filter desgined to drastically eliminate urban light pollution and maximize deep-sky contrast. Boasting a narrow 3nm full-width at half-maximum (FWHM), this filter isolates the critical emission lines of target nebulae with surgical precision while suppressing the surrounding broadband sky background. By isolating only H-alpha (656.3nm) and OIII (495.9nm & 500.7nm), the L-Ultimate captures pure emission data while blocking artificial light sources. It strongly blocks light from mercury vapor lamps. It also blocks light from sodium streetlights. It reduces natural skyglow caused by oxygen emissions high in the atmosphere. The result is significantly increased signal-to-noise ratio (SNR) and ink-black backgrounds, even from high-Bortle environments.
Compatibility Notice: Designed for versatility, the L-Ultimate is fully compatible with DSLRs, one-shot color (OSC) CMOS, monochrome CMOS, and CCD sensors. This filter is optimized for systems with a focal ratio of f/4 or slower, ensuring peak transmission efficiency without significant blueshift.
Check out Agena Astro's Youtube for the Ultimate Rundown!
The L-Ultimate in Action!
Flying Bat and Squid Nebulae
Credit: Tommaso Massimo Stella
The Lion nebula
Credit: Andrea Maggi
Veil Nebula
Credit: Tommy Lim KW (Malaysia)
The advantage of L-Ultimate is that it only passes the OIII (500.7 nm) and H a (656.3 nm) emission lines. It blocks all other light pollution emission lines. This means imaging captures only the nebula’s emission and reflection signals. Therefore, the sky background in the image is darker. This improves the contrast between the nebulae and the signal-to-noise ratio as much as possible. In areas with heavy light pollution, the product can selectively filter out light pollution and clutter. It passes nebula emission lines and helps reduce light pollution effects on astrophotography.
Why the L-Ultimate Beats the Glare
The L-Ultimate stands out from the rest of Optolong’s dual-narrowband lineup, like the L-eNhance and L-eXtreme, by shrinking its bandpass down to an ultra-tight dual-3nm bandwidth. By letting only the essential H-alpha and OIII emission lines pass through to your sensor, it delivers significantly darker sky backgrounds, striking structural contrast, and beautifully controlled stars. Optolong also optimized the L-Ultimate’s internal reflections, meaning you can finally say goodbye to distracting halos around bright target stars.
To achieve this, Optolong carefully mapped the exact wavelengths of deep-space nebulae against the messy spectrum of urban light pollution. The result is a specialized dual-3nm filter that fiercely blocks city glare while locking onto the vibrant, true colors of H-alpha and OIII. You can check out the exact spectral performance chart in the fourth product photo above!
Specifications
- Substrate: Optical Glass
- Size: 2" mounted (M48x0.75 thread)
- Thickness: 1.85mm
- FWHM: OIII 3nm, Ha 3nm
- Blocking Range: 300-1000nm
- Blocking: OD4
- Surface quality: 60/40
- Transmitted Wavefront RMS: λ/4
- Parallelism: 30 seconds
Useful Resources
Filter Cell Specifications
D = Filter Cell Diameter = 50.3 mm / 2.0 in
T = Total Filter Height = 6.8 mm / 0.26 in
C = Filter Cell Height (Excluding Male Thread) = 4.8 mm / 0.18 in
M = Male Thread Length = 2.0 mm / 0.07 in
F = USABLE Female Filter Thread Length = Not threaded, so you cannot stack additional filters
S = Glass Substrate Thickness = 2 mm / 0.07 in
CA = Clear Aperture = 44 mm / 1.73 in
Other Information
- Country of Manufacture: China
Optolong L-Ultimate: Fight Back Against Light Pollution!
The Optolong L-Ultimate is a professional-grade dual-bandpass filter desgined to drastically eliminate urban light pollution and maximize deep-sky contrast. Boasting a narrow 3nm full-width at half-maximum (FWHM), this filter isolates the critical emission lines of target nebulae with surgical precision while suppressing the surrounding broadband sky background. By isolating only H-alpha (656.3nm) and OIII (495.9nm & 500.7nm), the L-Ultimate captures pure emission data while blocking artificial light sources. It strongly blocks light from mercury vapor lamps. It also blocks light from sodium streetlights. It reduces natural skyglow caused by oxygen emissions high in the atmosphere. The result is significantly increased signal-to-noise ratio (SNR) and ink-black backgrounds, even from high-Bortle environments.
Compatibility Notice: Designed for versatility, the L-Ultimate is fully compatible with DSLRs, one-shot color (OSC) CMOS, monochrome CMOS, and CCD sensors. This filter is optimized for systems with a focal ratio of f/4 or slower, ensuring peak transmission efficiency without significant blueshift.
Check out Agena Astro's Youtube for the Ultimate Rundown!
The L-Ultimate in Action!
Flying Bat and Squid Nebulae
Credit: Tommaso Massimo Stella
The Lion nebula
Credit: Andrea Maggi
Veil Nebula
Credit: Tommy Lim KW (Malaysia)
The advantage of L-Ultimate is that it only passes the OIII (500.7 nm) and H a (656.3 nm) emission lines. It blocks all other light pollution emission lines. This means imaging captures only the nebula’s emission and reflection signals. Therefore, the sky background in the image is darker. This improves the contrast between the nebulae and the signal-to-noise ratio as much as possible. In areas with heavy light pollution, the product can selectively filter out light pollution and clutter. It passes nebula emission lines and helps reduce light pollution effects on astrophotography.
Why the L-Ultimate Beats the Glare
The L-Ultimate stands out from the rest of Optolong’s dual-narrowband lineup, like the L-eNhance and L-eXtreme, by shrinking its bandpass down to an ultra-tight dual-3nm bandwidth. By letting only the essential H-alpha and OIII emission lines pass through to your sensor, it delivers significantly darker sky backgrounds, striking structural contrast, and beautifully controlled stars. Optolong also optimized the L-Ultimate’s internal reflections, meaning you can finally say goodbye to distracting halos around bright target stars.
To achieve this, Optolong carefully mapped the exact wavelengths of deep-space nebulae against the messy spectrum of urban light pollution. The result is a specialized dual-3nm filter that fiercely blocks city glare while locking onto the vibrant, true colors of H-alpha and OIII. You can check out the exact spectral performance chart in the fourth product photo above!
Specifications
- Substrate: Optical Glass
- Size: 2" mounted (M48x0.75 thread)
- Thickness: 1.85mm
- FWHM: OIII 3nm, Ha 3nm
- Blocking Range: 300-1000nm
- Blocking: OD4
- Surface quality: 60/40
- Transmitted Wavefront RMS: λ/4
- Parallelism: 30 seconds
- 1x L-Ultimate Filter - 2"
- 1x Plastic Storage Case
- Restricts transmission down to 3nm for H-Alpha and OIII, blocking out urban skyglow for enhanced nebula contrast
- Features upgraded internal coatings engineered to eliminate distracting, bloated halos around bright target stars
- Delivers a boost to your signal-to-noise ratio by wiping out city glare and artificial light, leaving clean data that is easy to process.
Optolong L-Ultimate: Fight Back Against Light Pollution!
The Optolong L-Ultimate is a professional-grade dual-bandpass filter desgined to drastically eliminate urban light pollution and maximize deep-sky contrast. Boasting a narrow 3nm full-width at half-maximum (FWHM), this filter isolates the critical emission lines of target nebulae with surgical precision while suppressing the surrounding broadband sky background. By isolating only H-alpha (656.3nm) and OIII (495.9nm & 500.7nm), the L-Ultimate captures pure emission data while blocking artificial light sources. It strongly blocks light from mercury vapor lamps. It also blocks light from sodium streetlights. It reduces natural skyglow caused by oxygen emissions high in the atmosphere. The result is significantly increased signal-to-noise ratio (SNR) and ink-black backgrounds, even from high-Bortle environments.
Compatibility Notice: Designed for versatility, the L-Ultimate is fully compatible with DSLRs, one-shot color (OSC) CMOS, monochrome CMOS, and CCD sensors. This filter is optimized for systems with a focal ratio of f/4 or slower, ensuring peak transmission efficiency without significant blueshift.
Check out Agena Astro's Youtube for the Ultimate Rundown!
The L-Ultimate in Action!
Flying Bat and Squid Nebulae
Credit: Tommaso Massimo Stella
The Lion nebula
Credit: Andrea Maggi
Veil Nebula
Credit: Tommy Lim KW (Malaysia)
The advantage of L-Ultimate is that it only passes the OIII (500.7 nm) and H a (656.3 nm) emission lines. It blocks all other light pollution emission lines. This means imaging captures only the nebula’s emission and reflection signals. Therefore, the sky background in the image is darker. This improves the contrast between the nebulae and the signal-to-noise ratio as much as possible. In areas with heavy light pollution, the product can selectively filter out light pollution and clutter. It passes nebula emission lines and helps reduce light pollution effects on astrophotography.
Why the L-Ultimate Beats the Glare
The L-Ultimate stands out from the rest of Optolong’s dual-narrowband lineup, like the L-eNhance and L-eXtreme, by shrinking its bandpass down to an ultra-tight dual-3nm bandwidth. By letting only the essential H-alpha and OIII emission lines pass through to your sensor, it delivers significantly darker sky backgrounds, striking structural contrast, and beautifully controlled stars. Optolong also optimized the L-Ultimate’s internal reflections, meaning you can finally say goodbye to distracting halos around bright target stars.
To achieve this, Optolong carefully mapped the exact wavelengths of deep-space nebulae against the messy spectrum of urban light pollution. The result is a specialized dual-3nm filter that fiercely blocks city glare while locking onto the vibrant, true colors of H-alpha and OIII. You can check out the exact spectral performance chart in the fourth product photo above!
Specifications
- Substrate: Optical Glass
- Size: 2" mounted (M48x0.75 thread)
- Thickness: 1.85mm
- FWHM: OIII 3nm, Ha 3nm
- Blocking Range: 300-1000nm
- Blocking: OD4
- Surface quality: 60/40
- Transmitted Wavefront RMS: λ/4
- Parallelism: 30 seconds
Useful Resources
Filter Cell Specifications
D = Filter Cell Diameter = 50.3 mm / 2.0 in
T = Total Filter Height = 6.8 mm / 0.26 in
C = Filter Cell Height (Excluding Male Thread) = 4.8 mm / 0.18 in
M = Male Thread Length = 2.0 mm / 0.07 in
F = USABLE Female Filter Thread Length = Not threaded, so you cannot stack additional filters
S = Glass Substrate Thickness = 2 mm / 0.07 in
CA = Clear Aperture = 44 mm / 1.73 in
Other Information
- Country of Manufacture: China
- 1x L-Ultimate Filter - 2"
- 1x Plastic Storage Case
Optolong L-Ultimate Dual Bandpass Light Pollution Reduction Imaging Filter - 2"