Antlia 2.8nm Narrowband Sulfur II (SII) Ultra Imaging Filter - 36mm Round Unmounted
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PLEASE NOTE: Antlia is making a running change to their packaging. They are transitioning from 2-piece magnetic plastic cases to a smaller 1-piece non-magnetic design. Depending on the item(s) you order, you may randomly get one case type or the other or a mix of the two. We cannot entertain requests for any specific case type.
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 SII 2.8nm Ultra filter uses OHARA quartz glass and is manufactured under precisely controlled coating processes. The Ultra series are optimized with a FWHM (full width half maximum) of 2.8nm+/-0.5nm and a transmission efficiency >97% at the emission wavelength. The result is a very high Signal to Noise Ratio.
The OHARA quartz glass has an ultra-low thermal expansion coefficient with outstanding thermal and mechanical properties. When these superior glass characteristics are combined with advanced coating processes, these filters will provide excellent durability for imaging and research in the toughest environmental conditions.
All the 2.8nm Ultra filters are 100% scanned individually, all transmission and blocking (OD) data in the box are actual, measured spectra.
Compared with 3nm Pro series, 2.8nm Ultra series coated on OHARA quartz glass and showed higher transmittance SII＞97%. It is estimated that these filters will provide 20-30% signal improvement in your images as compared to the 3nm Pro series. In addition, the Ultra series has a 10% narrower FWHM 2.8nm+/-0.5nm. The Ultra series narrowband filters will allow you to capture improved contrast and structural detail.
Features:
- High transmittance（SII＞97%）and the narrowest FWHM 2.8nm+/-0.5nm to maximize contrast
- Flat-top spectrum minimizes the loss in transmission due to the Center Wavelength (CWL)-shift
- Out of band blocking specification is designed to OD5 (0.001%) to block interference from other wavelengths and minimize halos around bright stars
- Made of OHARA quartz glass, excellent durability and thermal stability, better fracture resistance and scratch resistance, improved coating resilience to cleaning
- Identical filter thickness to existing standards and double-sided fine polishing , with utmost care for parfocality
- SII 2.8nm Ultra filters can be used down to f/3.5 systems with minimal loss of signal. (This does not mean that optics with faster focal ratios will not be applicable, the flat-top design reduce the effect of wavelength shift and you can still use the 2.8nm Ultra narrowband)
- 100% of production are scanned individually, all transmission and blocking (OD) data in the box are actual, measured spectra and transmission
- All Antlia filters are coated to the edge of the substrate and unmounted narrowband filters are edge blackened to eliminate internal reflections from stray light
- Warranty: 3-years against delamination
Technical Specifications:
Sulfur-II
- FWHM: 2.8nm+/-0.5nm
- CWL (Central Wavelength): 672.4nm
- Peak Transmission: 97%
- Blocking: ≥OD5
- Filter Thickness: 2mm+/-0.05mm
Filter Ring:
- None. 36mm round unmounted
Not Recommended:
- Solar 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.
Other Information
- Country of Manufacture: China
The Antlia SII 2.8nm Ultra filter uses OHARA quartz glass and is manufactured under precisely controlled coating processes. The Ultra series are optimized with a FWHM (full width half maximum) of 2.8nm+/-0.5nm and a transmission efficiency >97% at the emission wavelength. The result is a very high Signal to Noise Ratio.
The OHARA quartz glass has an ultra-low thermal expansion coefficient with outstanding thermal and mechanical properties. When these superior glass characteristics are combined with advanced coating processes, these filters will provide excellent durability for imaging and research in the toughest environmental conditions.
All the 2.8nm Ultra filters are 100% scanned individually, all transmission and blocking (OD) data in the box are actual, measured spectra.
Compared with 3nm Pro series, 2.8nm Ultra series coated on OHARA quartz glass and showed higher transmittance SII＞97%. It is estimated that these filters will provide 20-30% signal improvement in your images as compared to the 3nm Pro series. In addition, the Ultra series has a 10% narrower FWHM 2.8nm+/-0.5nm. The Ultra series narrowband filters will allow you to capture improved contrast and structural detail.
Features:
- High transmittance（SII＞97%）and the narrowest FWHM 2.8nm+/-0.5nm to maximize contrast
- Flat-top spectrum minimizes the loss in transmission due to the Center Wavelength (CWL)-shift
- Out of band blocking specification is designed to OD5 (0.001%) to block interference from other wavelengths and minimize halos around bright stars
- Made of OHARA quartz glass, excellent durability and thermal stability, better fracture resistance and scratch resistance, improved coating resilience to cleaning
- Identical filter thickness to existing standards and double-sided fine polishing , with utmost care for parfocality
- SII 2.8nm Ultra filters can be used down to f/3.5 systems with minimal loss of signal. (This does not mean that optics with faster focal ratios will not be applicable, the flat-top design reduce the effect of wavelength shift and you can still use the 2.8nm Ultra narrowband)
- 100% of production are scanned individually, all transmission and blocking (OD) data in the box are actual, measured spectra and transmission
- All Antlia filters are coated to the edge of the substrate and unmounted narrowband filters are edge blackened to eliminate internal reflections from stray light
- Warranty: 3-years against delamination
Technical Specifications:
Sulfur-II
- FWHM: 2.8nm+/-0.5nm
- CWL (Central Wavelength): 672.4nm
- Peak Transmission: 97%
- Blocking: ≥OD5
- Filter Thickness: 2mm+/-0.05mm
Filter Ring:
- None. 36mm round unmounted
Not Recommended:
- Solar 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.
PLEASE NOTE: Antlia is making a running change to their packaging. They are transitioning from 2-piece magnetic plastic cases to a smaller 1-piece non-magnetic design. Depending on the item(s) you order, you may randomly get one case type or the other or a mix of the two. We cannot entertain requests for any specific case type.
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 SII 2.8nm Ultra filter uses OHARA quartz glass and is manufactured under precisely controlled coating processes. The Ultra series are optimized with a FWHM (full width half maximum) of 2.8nm+/-0.5nm and a transmission efficiency >97% at the emission wavelength. The result is a very high Signal to Noise Ratio.
The OHARA quartz glass has an ultra-low thermal expansion coefficient with outstanding thermal and mechanical properties. When these superior glass characteristics are combined with advanced coating processes, these filters will provide excellent durability for imaging and research in the toughest environmental conditions.
All the 2.8nm Ultra filters are 100% scanned individually, all transmission and blocking (OD) data in the box are actual, measured spectra.
Compared with 3nm Pro series, 2.8nm Ultra series coated on OHARA quartz glass and showed higher transmittance SII＞97%. It is estimated that these filters will provide 20-30% signal improvement in your images as compared to the 3nm Pro series. In addition, the Ultra series has a 10% narrower FWHM 2.8nm+/-0.5nm. The Ultra series narrowband filters will allow you to capture improved contrast and structural detail.
Features:
- High transmittance（SII＞97%）and the narrowest FWHM 2.8nm+/-0.5nm to maximize contrast
- Flat-top spectrum minimizes the loss in transmission due to the Center Wavelength (CWL)-shift
- Out of band blocking specification is designed to OD5 (0.001%) to block interference from other wavelengths and minimize halos around bright stars
- Made of OHARA quartz glass, excellent durability and thermal stability, better fracture resistance and scratch resistance, improved coating resilience to cleaning
- Identical filter thickness to existing standards and double-sided fine polishing , with utmost care for parfocality
- SII 2.8nm Ultra filters can be used down to f/3.5 systems with minimal loss of signal. (This does not mean that optics with faster focal ratios will not be applicable, the flat-top design reduce the effect of wavelength shift and you can still use the 2.8nm Ultra narrowband)
- 100% of production are scanned individually, all transmission and blocking (OD) data in the box are actual, measured spectra and transmission
- All Antlia filters are coated to the edge of the substrate and unmounted narrowband filters are edge blackened to eliminate internal reflections from stray light
- Warranty: 3-years against delamination
Technical Specifications:
Sulfur-II
- FWHM: 2.8nm+/-0.5nm
- CWL (Central Wavelength): 672.4nm
- Peak Transmission: 97%
- Blocking: ≥OD5
- Filter Thickness: 2mm+/-0.05mm
Filter Ring:
- None. 36mm round unmounted
Not Recommended:
- Solar 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.
Other Information
- Country of Manufacture: China