Antlia ALP-T Dual Narrowband OIII (5nm) & H-a (5nm) Filter for f/3.6 & Slower Telescopes - 2" Mounted
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IMPORTANT: Please read this important note below before buying Antlia narrowband filters. No returns will be accepted for Antlia narrowband filters exhibiting halos around bright stars as disclosed below.
Please note that some users may see halos around bright stars in images made with this filter. Such halos have been observed with filters from other leading manufacturers and in the previous generation of Antlia narrowband filters as well. These halos can be caused and/or made worse by other optical accessories in the imaging train, their relative positions, telescope design/optics, camera, software, or a combination thereof. In general, OIII filters seem to have a higher propensity to show halos compared to H-alpha or S-II filters, but in rare cases the latter filters can also exhibit faint halos around bright stars.
Antlia has made great strides in their coatings to minimize haloing of bright stars, but you may still observe this effect to some degree. See the sample OIII image below of Alnitak (magnitude 1.74) and IC434 in Orion (SkyRover 155mm Apo, ZWO 6200MM-P Camera, 20 min exposure) provided by Antlia. In most cases, haloing will not affect your image unless you have very bright stars in the field of view.
Please note we are unable to accept returns of any Antlia narrowband filters if you do observe this haloing effect in your images.
If you must ensure there are no detectable halos in your images, you may want to consider Astrodon or Chroma narrowband filters instead. These filters, however, cost two to three times as much as Antlia 3nm filters do. Antlia is being honest and upfront. They are the ones telling us about these halos, that their filters are great for the money but still not as good as Astrodon/Chroma, and pointing out that with this full disclosure, they will not accept returns. They are leaving it up to the customer to decide if this is good enough for them or not. We believe that for most imaging applications, Antlia filters continue to offer excellent value for astrophotographers and these continue to be among our top sellers.
The Antlia ALP-T dual band 5nm filter is a dual line-pass filter which was designed to be used primarily with one-shot color (OSC) cameras such as DSLR's or astronomical OSC cameras. It can also be used as a narrowband filter for monochrome cameras to save imaging time. The advanced multi-coatings on our ALP-T ultra dual band filter effectively isolates the red Ha and the blue-green OIII lines light from emission nebulae, with almost total suppression of optical density (OD) 4.5 on unwanted wavelengths from light pollution, moonlight, and airglow. The result is that our ALP-T dual band 5nm filter creates a superior signal-to-noise ratio and better contrast in your images.
The filter enables the capture of the two main emission nebulae bands at the same time, whilst suppressing unwanted light pollution. It enables you to capture cleaner data and reduces the post processing efforts to isolate faint details from the background light pollution.
As Antlia ALP-T dual band 5nm filter looks golden yellow to the naked eye, we also call it the Golden filter.
Application and Performance:
- Engineered specifically for use with DSLR, CMOS, and CCD color cameras and for telescopes f/3.6 and larger (slower)
- Suppression of optical density (OD) 4.5 on unwanted visual wavelengths adds signal-to-noise
- Extremely steep bandpass edges minimize internal reflections
- Ideal flat-top and moderate bandpass reducing spectrum down shifts
- Ion Gun Assisted Deposition coating technology on the double-sided polished substrate making it the most consistent and accurate light pollution suppression filter
- Good performance at focal ratios slower than F3.6 with contrast increasing as focal ratio increases
- Designed to suppress artificial lighting from Bortle scale 1 to Bortle scale 8
- Near IR (NIR) is blocked up to 1100nm
Technical Data:
Hydrogen-alpha
- FWHM: 5nm
- CWL (Central Wavelength): 656.3nm
- Peak Transmission: 90%
- Blocking: ≥OD4.5 @ 300-1100nm
- Filter Thickness: 2mm+/-0.05mm
Oxygen III
- FWHM: 5nm
- CWL (Central Wavelength): 500.7nm
- Peak Transmission: 82%
- Blocking: ≥OD4.5 @ 300-1100nm
- Filter Thickness: 2mm+/-0.05mm
Filter Ring:
- 2’’ Mounted (M48*0.75 thread)
- Ultra-thin filter cell to minimize vignetting by maximizing possible clear aperture
- Black Anodized Finish
- Laser Engraving, No Fading
Not Recommended:
- Solar Observing and imaging
- Night visual observation
- DO NOT LOOK AT THE SUN WITH ANTLIA FILTERS. Serious eye damage will result if you fail to observe the warning.
Useful Resources
Filter Cell Specifications
D = Filter Cell Diameter = 50.3 mm / 2.0 in
T = Total Filter Height = 7.3 mm / 0.28 in
C = Filter Cell Height (Excluding Male Thread) = 4.9 mm / 0.19 in
M = Male Thread Length = 2.5 mm / 0.09 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 = 45 mm / 1.77 in
Other Information
- Country of Manufacture: China
The Antlia ALP-T dual band 5nm filter is a dual line-pass filter which was designed to be used primarily with one-shot color (OSC) cameras such as DSLR's or astronomical OSC cameras. It can also be used as a narrowband filter for monochrome cameras to save imaging time. The advanced multi-coatings on our ALP-T ultra dual band filter effectively isolates the red Ha and the blue-green OIII lines light from emission nebulae, with almost total suppression of optical density (OD) 4.5 on unwanted wavelengths from light pollution, moonlight, and airglow. The result is that our ALP-T dual band 5nm filter creates a superior signal-to-noise ratio and better contrast in your images.
The filter enables the capture of the two main emission nebulae bands at the same time, whilst suppressing unwanted light pollution. It enables you to capture cleaner data and reduces the post processing efforts to isolate faint details from the background light pollution.
As Antlia ALP-T dual band 5nm filter looks golden yellow to the naked eye, we also call it the Golden filter.
Application and Performance:
- Engineered specifically for use with DSLR, CMOS, and CCD color cameras and for telescopes f/3.6 and larger (slower)
- Suppression of optical density (OD) 4.5 on unwanted visual wavelengths adds signal-to-noise
- Extremely steep bandpass edges minimize internal reflections
- Ideal flat-top and moderate bandpass reducing spectrum down shifts
- Ion Gun Assisted Deposition coating technology on the double-sided polished substrate making it the most consistent and accurate light pollution suppression filter
- Good performance at focal ratios slower than F3.6 with contrast increasing as focal ratio increases
- Designed to suppress artificial lighting from Bortle scale 1 to Bortle scale 8
- Near IR (NIR) is blocked up to 1100nm
Technical Data:
Hydrogen-alpha
- FWHM: 5nm
- CWL (Central Wavelength): 656.3nm
- Peak Transmission: 90%
- Blocking: ≥OD4.5 @ 300-1100nm
- Filter Thickness: 2mm+/-0.05mm
Oxygen III
- FWHM: 5nm
- CWL (Central Wavelength): 500.7nm
- Peak Transmission: 82%
- Blocking: ≥OD4.5 @ 300-1100nm
- Filter Thickness: 2mm+/-0.05mm
Filter Ring:
- 2’’ Mounted (M48*0.75 thread)
- Ultra-thin filter cell to minimize vignetting by maximizing possible clear aperture
- Black Anodized Finish
- Laser Engraving, No Fading
Not Recommended:
- Solar Observing and imaging
- Night visual observation
- DO NOT LOOK AT THE SUN WITH ANTLIA FILTERS. Serious eye damage will result if you fail to observe the warning.
IMPORTANT: Please read this important note below before buying Antlia narrowband filters. No returns will be accepted for Antlia narrowband filters exhibiting halos around bright stars as disclosed below.
Please note that some users may see halos around bright stars in images made with this filter. Such halos have been observed with filters from other leading manufacturers and in the previous generation of Antlia narrowband filters as well. These halos can be caused and/or made worse by other optical accessories in the imaging train, their relative positions, telescope design/optics, camera, software, or a combination thereof. In general, OIII filters seem to have a higher propensity to show halos compared to H-alpha or S-II filters, but in rare cases the latter filters can also exhibit faint halos around bright stars.
Antlia has made great strides in their coatings to minimize haloing of bright stars, but you may still observe this effect to some degree. See the sample OIII image below of Alnitak (magnitude 1.74) and IC434 in Orion (SkyRover 155mm Apo, ZWO 6200MM-P Camera, 20 min exposure) provided by Antlia. In most cases, haloing will not affect your image unless you have very bright stars in the field of view.
Please note we are unable to accept returns of any Antlia narrowband filters if you do observe this haloing effect in your images.
If you must ensure there are no detectable halos in your images, you may want to consider Astrodon or Chroma narrowband filters instead. These filters, however, cost two to three times as much as Antlia 3nm filters do. Antlia is being honest and upfront. They are the ones telling us about these halos, that their filters are great for the money but still not as good as Astrodon/Chroma, and pointing out that with this full disclosure, they will not accept returns. They are leaving it up to the customer to decide if this is good enough for them or not. We believe that for most imaging applications, Antlia filters continue to offer excellent value for astrophotographers and these continue to be among our top sellers.
The Antlia ALP-T dual band 5nm filter is a dual line-pass filter which was designed to be used primarily with one-shot color (OSC) cameras such as DSLR's or astronomical OSC cameras. It can also be used as a narrowband filter for monochrome cameras to save imaging time. The advanced multi-coatings on our ALP-T ultra dual band filter effectively isolates the red Ha and the blue-green OIII lines light from emission nebulae, with almost total suppression of optical density (OD) 4.5 on unwanted wavelengths from light pollution, moonlight, and airglow. The result is that our ALP-T dual band 5nm filter creates a superior signal-to-noise ratio and better contrast in your images.
The filter enables the capture of the two main emission nebulae bands at the same time, whilst suppressing unwanted light pollution. It enables you to capture cleaner data and reduces the post processing efforts to isolate faint details from the background light pollution.
As Antlia ALP-T dual band 5nm filter looks golden yellow to the naked eye, we also call it the Golden filter.
Application and Performance:
- Engineered specifically for use with DSLR, CMOS, and CCD color cameras and for telescopes f/3.6 and larger (slower)
- Suppression of optical density (OD) 4.5 on unwanted visual wavelengths adds signal-to-noise
- Extremely steep bandpass edges minimize internal reflections
- Ideal flat-top and moderate bandpass reducing spectrum down shifts
- Ion Gun Assisted Deposition coating technology on the double-sided polished substrate making it the most consistent and accurate light pollution suppression filter
- Good performance at focal ratios slower than F3.6 with contrast increasing as focal ratio increases
- Designed to suppress artificial lighting from Bortle scale 1 to Bortle scale 8
- Near IR (NIR) is blocked up to 1100nm
Technical Data:
Hydrogen-alpha
- FWHM: 5nm
- CWL (Central Wavelength): 656.3nm
- Peak Transmission: 90%
- Blocking: ≥OD4.5 @ 300-1100nm
- Filter Thickness: 2mm+/-0.05mm
Oxygen III
- FWHM: 5nm
- CWL (Central Wavelength): 500.7nm
- Peak Transmission: 82%
- Blocking: ≥OD4.5 @ 300-1100nm
- Filter Thickness: 2mm+/-0.05mm
Filter Ring:
- 2’’ Mounted (M48*0.75 thread)
- Ultra-thin filter cell to minimize vignetting by maximizing possible clear aperture
- Black Anodized Finish
- Laser Engraving, No Fading
Not Recommended:
- Solar Observing and imaging
- Night visual observation
- DO NOT LOOK AT THE SUN WITH ANTLIA FILTERS. Serious eye damage will result if you fail to observe the warning.
Useful Resources
Filter Cell Specifications
D = Filter Cell Diameter = 50.3 mm / 2.0 in
T = Total Filter Height = 7.3 mm / 0.28 in
C = Filter Cell Height (Excluding Male Thread) = 4.9 mm / 0.19 in
M = Male Thread Length = 2.5 mm / 0.09 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 = 45 mm / 1.77 in
Other Information
- Country of Manufacture: China
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Antlia ALP-T Dual Narrowband OIII (5nm) & H-a (5nm) Filter for f/3.6 & Slower Telescopes - 2" Mounted