Antlia ALP-T Dual Narrowband OIII (5nm) & H-a (5nm) Highspeed Filter for f/2.2 - f/4 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.
ALP-T Dual Band 5nm Highspeed Filters # ALP-T-2-HS are further optimized to work with high-speed imaging systems by shifting slightly the passband and center wavelength. Using these highspeed filters between optics f/2.2 and f/3.6 shows much stronger and more contrasted in nebulae imaging compared to the standard version.
For optics f-ratios slower than f/3.6, the standard ALP-T Dual Band 5nm filter is highly recommended. Meanwhile, if you seek the best possible performance with any optics faster than f/3.6, the highspeed version is the best choice.
But keep in mind, the blue shift data by the computer simulation indicates narrowband filter shifts its bandwidth to shorter wavelengths with faster optics than f/2, transmission at the emission wavelength may decrease perhaps 15%-20%. Although the Antlia ALP-T highspeed filter has similar transmission rates reduction in the H-a and OIII when the filter is used on fast optics, based on current standard version users’ data, it is evident that the filter still has the high performance of increase in emission nebula contrast and minimized halo.
The highspeed version price is the same as the standard filters and double benefits for the high-speed optics users. Worth mentioning is that Antlia inspected and measured products piece by piece with one of Agilent Cary’s professional spectrophotometer, resolution/slit width is up to 0.2nm, which make us provide highly reliable and consistent products to you.
The Antlia ALP-T dual band 5nm series filter is a dual line-pass filter that was designed to be used primarily with one-shot color (OSC) cameras such as DSLR's and 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 isolate 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.
Application and Performance:
- Designed especially for fast astronomy optics, in particular f-ratios f/2.2 to f/3.6
- Engineered specifically for use with DSLR, CMOS, and CCD color cameras
- Suppression of optical density (OD) 4.5 on unwanted 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
- Designed to suppress artificial lighting from Bortle scale 1 to Bortle scale 8
- Near IR (NIR) is blocked up to 1050nm
Technical Data:
Hydrogen-alpha
- FWHM: 5nm
- CWL (Central Wavelength): 657.8nm
- Peak Transmission: 88%
- Blocking: ≥OD4.5 @ 300-1050nm
- Filter Thickness: 2mm+/-0.05mm
Oxygen III
- FWHM: 5nm
- CWL (Central Wavelength): 502.2nm
- Peak Transmission: 82%
- Blocking: ≥OD4.5 @ 300-1050nm
- 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
ALP-T Dual Band 5nm Highspeed Filters # ALP-T-2-HS are further optimized to work with high-speed imaging systems by shifting slightly the passband and center wavelength. Using these highspeed filters between optics f/2.2 and f/3.6 shows much stronger and more contrasted in nebulae imaging compared to the standard version.
For optics f-ratios slower than f/3.6, the standard ALP-T Dual Band 5nm filter is highly recommended. Meanwhile, if you seek the best possible performance with any optics faster than f/3.6, the highspeed version is the best choice.
But keep in mind, the blue shift data by the computer simulation indicates narrowband filter shifts its bandwidth to shorter wavelengths with faster optics than f/2, transmission at the emission wavelength may decrease perhaps 15%-20%. Although the Antlia ALP-T highspeed filter has similar transmission rates reduction in the H-a and OIII when the filter is used on fast optics, based on current standard version users’ data, it is evident that the filter still has the high performance of increase in emission nebula contrast and minimized halo.
The highspeed version price is the same as the standard filters and double benefits for the high-speed optics users. Worth mentioning is that Antlia inspected and measured products piece by piece with one of Agilent Cary’s professional spectrophotometer, resolution/slit width is up to 0.2nm, which make us provide highly reliable and consistent products to you.
The Antlia ALP-T dual band 5nm series filter is a dual line-pass filter that was designed to be used primarily with one-shot color (OSC) cameras such as DSLR's and 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 isolate 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.
Application and Performance:
- Designed especially for fast astronomy optics, in particular f-ratios f/2.2 to f/3.6
- Engineered specifically for use with DSLR, CMOS, and CCD color cameras
- Suppression of optical density (OD) 4.5 on unwanted 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
- Designed to suppress artificial lighting from Bortle scale 1 to Bortle scale 8
- Near IR (NIR) is blocked up to 1050nm
Technical Data:
Hydrogen-alpha
- FWHM: 5nm
- CWL (Central Wavelength): 657.8nm
- Peak Transmission: 88%
- Blocking: ≥OD4.5 @ 300-1050nm
- Filter Thickness: 2mm+/-0.05mm
Oxygen III
- FWHM: 5nm
- CWL (Central Wavelength): 502.2nm
- Peak Transmission: 82%
- Blocking: ≥OD4.5 @ 300-1050nm
- 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.
ALP-T Dual Band 5nm Highspeed Filters # ALP-T-2-HS are further optimized to work with high-speed imaging systems by shifting slightly the passband and center wavelength. Using these highspeed filters between optics f/2.2 and f/3.6 shows much stronger and more contrasted in nebulae imaging compared to the standard version.
For optics f-ratios slower than f/3.6, the standard ALP-T Dual Band 5nm filter is highly recommended. Meanwhile, if you seek the best possible performance with any optics faster than f/3.6, the highspeed version is the best choice.
But keep in mind, the blue shift data by the computer simulation indicates narrowband filter shifts its bandwidth to shorter wavelengths with faster optics than f/2, transmission at the emission wavelength may decrease perhaps 15%-20%. Although the Antlia ALP-T highspeed filter has similar transmission rates reduction in the H-a and OIII when the filter is used on fast optics, based on current standard version users’ data, it is evident that the filter still has the high performance of increase in emission nebula contrast and minimized halo.
The highspeed version price is the same as the standard filters and double benefits for the high-speed optics users. Worth mentioning is that Antlia inspected and measured products piece by piece with one of Agilent Cary’s professional spectrophotometer, resolution/slit width is up to 0.2nm, which make us provide highly reliable and consistent products to you.
The Antlia ALP-T dual band 5nm series filter is a dual line-pass filter that was designed to be used primarily with one-shot color (OSC) cameras such as DSLR's and 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 isolate 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.
Application and Performance:
- Designed especially for fast astronomy optics, in particular f-ratios f/2.2 to f/3.6
- Engineered specifically for use with DSLR, CMOS, and CCD color cameras
- Suppression of optical density (OD) 4.5 on unwanted 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
- Designed to suppress artificial lighting from Bortle scale 1 to Bortle scale 8
- Near IR (NIR) is blocked up to 1050nm
Technical Data:
Hydrogen-alpha
- FWHM: 5nm
- CWL (Central Wavelength): 657.8nm
- Peak Transmission: 88%
- Blocking: ≥OD4.5 @ 300-1050nm
- Filter Thickness: 2mm+/-0.05mm
Oxygen III
- FWHM: 5nm
- CWL (Central Wavelength): 502.2nm
- Peak Transmission: 82%
- Blocking: ≥OD4.5 @ 300-1050nm
- 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) Highspeed Filter for f/2.2 - f/4 Telescopes - 2" Mounted