Antlia 3nm Narrowband Sulfur II (SII) Pro Highspeed Imaging Filter for f/2.6 - f/3.6 Telesco...
Ships by Next Business Day
Contiguous US Customers:
All items we sell ship for free within the Contiguous US. Shipping will be via the cheapest shipping method which will vary depending on the items in your order. During checkout, you may also be shown other optional faster shipping choices.
US Customers in Hawaii and Alaska:
Free shipping applies to almost all products. A few large telescopes and mounts are excluded from this free shipping offer. For these items, please contact us to obtain a shipping quote before you check out using the online shopping cart.
International Customers:
Free shipping does not apply to international orders. During check-out, you will be presented with several shipping choices and costs. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions.
Antlia's Sulfur II (SII) 3nm Pro Highspeed Filter is further optimized for high-speed imaging systems by pre-shifting the center wavelength. This specially-optimized version will provide significantly SNR (Signal to Noise Ratio) for the fast telescopes with focal ratio between f/2.6 and f/3.6 than the standard 3nm Pro version.
The optical light path of a telescope is cone-shaped, which creates an angle, and the center wavelength of the interference filter will shift toward shorter (blue) wavelengths as the angle of incidence((AOI) increases; the greater the angle, the greater the shift. The amount of beam deviation depends on the refractive index and the thickness of the substrate. The blue shift data by the simulation indicates that at a focal ratio of f/2.6, the angle of incidence of the light cone is 10°and its bandwidth shift 2.2nm to shorter wavelengths. Therefore, the Highspeed 3nm Pro narrowband filters are designed to be pre-shifted by 1.2nm towards the longer (red) end in order to compensate for the Blueshift and ensure high signal acquisition by telescopes with fast focal ratios.
Using this highspeed Sulfur II (SII) 3nm Pro narrowband filter for the telescopes with focal ratio between f/2.6 and f/3.6 shows much stronger and more contrasted in astronomy imaging compared to the standard Pro version.
For optics f-ratios slower than f/3.6, the standard 3nm Pro filters are highly recommended. Meanwhile, if you use optics faster than f/2.6, the 4.5nm EDGE filters are the good choice.
Features:
- High transmittance SII＞90% and 3nm bandwidth to maximize contrast
- Antlia narrowband Pro Highspeed filters can be used with focal ratio f/2.6-f3.6 systems with minimal loss of signal
- Improved sharp cut-off astrophotography 3nm Pro series filters are designed to minimize halos around bright stars
- The out of band blocking specification is rated OD5 (0.001%) which delivers an excellent SNR (signal to noise ratio) and effective cut-off rate to minimize interference from other wavelengths
- A single substrate to eliminate internal reflections
- Narrowband Objects: Emission Nebulae, Planetary, Wolf Rayet Nebulae and Supernova Remnants
- Use in light polluted areas and dark sites
- Extends imaging time when the moon is up
- All Antlia unmounted narrowband Highspeed filters are edge blackened to eliminate internal reflections from stray light
- Superior optical reliability reduces post image processing
- Basic Substrate: Optical, Single / Non-glued substrate
- Surface Quality: S/D (scratch/dig)= 60/40 (Refer to MIL-O-13830)
- Transmitted Wavefront: Lambda/4 or better.
- Parallelism: less than 30 arcsec
- Warranty: 3-years against delamination
Technical Specifications:
- FWHM: 3nm
- CWL (Central Wavelength): 673.6nm
- Peak Transmission: 90%
- Blocking: ≥OD5 @ 300-1000nm
- Filter Thickness: 2mm+/-0.05mm
Filter Ring:
- 2’’ mounted (M48x0.75)
- Ultra-thin filter cell to minimize vignetting by maximize possible clear aperture
- Black anodized finish
- Laser engraving No fading
Not Recommended:
- Solar imaging
- Night visual observation
Not Permitted:
- DO NOT LOOK AT THE SUN WITH THIS FILTER
- Serious eye damage will result if you fail to observe the warning.
| Free Shipping Graphic | Free US Shipping |
|---|---|
| Hide Found a better Shipped Price on Frontend? | No |
Antlia's Sulfur II (SII) 3nm Pro Highspeed Filter is further optimized for high-speed imaging systems by pre-shifting the center wavelength. This specially-optimized version will provide significantly SNR (Signal to Noise Ratio) for the fast telescopes with focal ratio between f/2.6 and f/3.6 than the standard 3nm Pro version.
The optical light path of a telescope is cone-shaped, which creates an angle, and the center wavelength of the interference filter will shift toward shorter (blue) wavelengths as the angle of incidence((AOI) increases; the greater the angle, the greater the shift. The amount of beam deviation depends on the refractive index and the thickness of the substrate. The blue shift data by the simulation indicates that at a focal ratio of f/2.6, the angle of incidence of the light cone is 10°and its bandwidth shift 2.2nm to shorter wavelengths. Therefore, the Highspeed 3nm Pro narrowband filters are designed to be pre-shifted by 1.2nm towards the longer (red) end in order to compensate for the Blueshift and ensure high signal acquisition by telescopes with fast focal ratios.
Using this highspeed Sulfur II (SII) 3nm Pro narrowband filter for the telescopes with focal ratio between f/2.6 and f/3.6 shows much stronger and more contrasted in astronomy imaging compared to the standard Pro version.
For optics f-ratios slower than f/3.6, the standard 3nm Pro filters are highly recommended. Meanwhile, if you use optics faster than f/2.6, the 4.5nm EDGE filters are the good choice.
Features:
- High transmittance SII＞90% and 3nm bandwidth to maximize contrast
- Antlia narrowband Pro Highspeed filters can be used with focal ratio f/2.6-f3.6 systems with minimal loss of signal
- Improved sharp cut-off astrophotography 3nm Pro series filters are designed to minimize halos around bright stars
- The out of band blocking specification is rated OD5 (0.001%) which delivers an excellent SNR (signal to noise ratio) and effective cut-off rate to minimize interference from other wavelengths
- A single substrate to eliminate internal reflections
- Narrowband Objects: Emission Nebulae, Planetary, Wolf Rayet Nebulae and Supernova Remnants
- Use in light polluted areas and dark sites
- Extends imaging time when the moon is up
- All Antlia unmounted narrowband Highspeed filters are edge blackened to eliminate internal reflections from stray light
- Superior optical reliability reduces post image processing
- Basic Substrate: Optical, Single / Non-glued substrate
- Surface Quality: S/D (scratch/dig)= 60/40 (Refer to MIL-O-13830)
- Transmitted Wavefront: Lambda/4 or better.
- Parallelism: less than 30 arcsec
- Warranty: 3-years against delamination
Technical Specifications:
- FWHM: 3nm
- CWL (Central Wavelength): 673.6nm
- Peak Transmission: 90%
- Blocking: ≥OD5 @ 300-1000nm
- Filter Thickness: 2mm+/-0.05mm
Filter Ring:
- 2’’ mounted (M48x0.75)
- Ultra-thin filter cell to minimize vignetting by maximize possible clear aperture
- Black anodized finish
- Laser engraving No fading
Not Recommended:
- Solar imaging
- Night visual observation
Not Permitted:
- DO NOT LOOK AT THE SUN WITH THIS FILTER
- Serious eye damage will result if you fail to observe the warning.
| Free Shipping Graphic | Free US Shipping |
|---|---|
| Hide Found a better Shipped Price on Frontend? | No |
Antlia 3nm Narrowband Sulfur II (SII) Pro Highspeed Imaging Filter for f/2.6 - f/3.6 Telescopes - 2" Mounted