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IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.
SVBONY SV227 SII 5nm Narrowband Filter - 2"
SVBONY SV227 SII 5nm Narrowband Filter - 2"
SVBONY SV227 SII 5nm Narrowband Filter - 2"
SVBONY SV227 SII 5nm Narrowband Filter - 2"
SVBONY SV227 SII 5nm Narrowband Filter - 2"
SVBONY SV227 SII 5nm Narrowband Filter - 2"
SVBONY SV227 SII 5nm Narrowband Filter - 2"
SVBONY SV227 SII 5nm Narrowband Filter - 2"
SVBONY SV227 SII 5nm Narrowband Filter - 2"
SVBONY SV227 SII 5nm Narrowband Filter - 2"
SVBONY SV227 SII 5nm Narrowband Filter - 2"
SVBONY SV227 SII 5nm Narrowband Filter - 2"

SVBONY SV227 SII 5nm Narrowband Filter - 2"

by SVBONY
SKU SV-W9187DA
$93.33 - $93.33
$93.33
$93.33 - $93.33
$93.33
Price Match Policy!
  • Captures Sulfur-II (SII) emission at a 672nm center wavelength
  • Extremely narrow 5nm bandpass for maximum contrast
  • Peak light transmission of ≥90% for strong signal
  • OD5 blocking rejects light pollution and unwanted wavelengths
  • Standard 2-inch format with M48x0.75 filter threads
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • SVBONY SV227 2" SII 5nm Narrowband CCD Filter for Deep Sky

    The SVBONY SV227 2" SII 5nm Narrowband CCD Filter isolates the critical 672nm Sulfur-II emission line with a tight 5nm full width at half maximum (FWHM) for extreme-contrast imaging. With a peak transmittance of ≥90% and deep out-of-band blocking rated at OD5, the SV227 ensures a pure signal from emission nebulae reaches your sensor. The filter is built on a 1.85mm thick substrate with 1/4λ surface parallelism and fits standard 2-inch filter wheels via its M48x0.75 thread.

    The 5nm Bandpass: Isolating the 672nm SII Line

    By restricting the incoming light to a narrow 5nm window centered on the 672nm SII line, the SV227 dramatically increases the contrast of emission nebulae against the skyglow background. This narrow bandpass is significantly more effective at rejecting light pollution from streetlights and moonlight than wider filters, darkening the sky background and allowing faint structural details to emerge during long exposures.

    Optical Precision: ≥90% Transmission with OD5 Blocking

    A narrow filter is only effective if it transmits the light you want while rejecting everything else. The SV227 achieves a high peak transmittance of ≥90% within its passband, ensuring that valuable photons from your target aren't lost. Simultaneously, its OD5 blocking rating attenuates unwanted wavelengths by a factor of 100,000, delivering a clean signal free of IR contamination and reflected halos, which is critical for producing sharp stars and clean nebulosity.

    • Substrate Quality: The 1.85mm substrate with a 1/4λ surface parallelism rating ensures that the filter will not introduce distortions into your optical train.
    • Clear Aperture: A 44mm clear aperture minimizes the risk of vignetting, even with fast optical systems or large-format sensors.

    The SV227 in SHO Imaging: Completing the Hubble Palette

    The SV227 is the essential "S" channel for creating tricolor narrowband images in the popular Hubble Palette (SHO). When combined with H-alpha and OIII filters of a similar 5nm bandpass, it allows you to assign each emission line to a different color channel (SII=Red, Ha=Green, OIII=Blue) to reveal the complex chemical composition of targets like the Pillars of Creation in the Eagle Nebula (M16).

    The shared 5nm bandpass across your filter set ensures that star sizes are consistent between channels, simplifying post-processing and resulting in a more refined final image. The SV227's M48x0.75 thread makes it a direct fit for any standard 2-inch filter wheel or drawer.

  • What is the main purpose of the SVBONY SV227 SII filter?

    The SVBONY SV227 is a specialized narrowband filter for astrophotography. It is designed to isolate the Sulfur-II (SII) emission line at 672nm, which is prominent in many emission nebulae. This allows you to capture high-contrast images of these objects, even from light-polluted locations, and is a critical component for creating "Hubble Palette" color images.

    How does the SV227's 5nm bandpass compare to a 7nm filter?

    A 5nm bandpass is narrower than a 7nm one, offering superior rejection of light pollution and higher contrast on faint nebulae. The trade-off is that it requires slightly longer exposure times to achieve the same signal level. For heavily light-polluted skies or for imagers seeking maximum detail, the 5nm bandpass of the SV227 is the better choice.

    Will the SVBONY SV227 work for imaging the Soul Nebula (IC 1848) with my monochrome camera?

    Yes, absolutely. The Soul Nebula is rich in glowing ionized gas, including Sulfur-II. Using the SVBONY SV227 with a monochrome camera is the ideal way to capture the faint, intricate structures within this nebula that are often lost in broadband or wider-filter images. It will provide the "S" data needed for a full SHO color composite.

    Is the 5nm bandpass of the SV227 suitable for my f/5 Newtonian telescope?

    Yes, a 5nm filter like the SV227 is generally fine for systems down to f/4. In very fast optical systems (f/4 and faster), narrowband filters can experience a slight shift in their center wavelength. However, at f/5, the SV227 will perform very well, providing excellent contrast without significant band-shifting issues.

    What does OD5 blocking mean for my images with the SV227 filter?

    OD5 (Optical Density 5) means the filter blocks out-of-band light by a factor of 100,000 (10^5). This is a very high level of rejection that ensures only the desired 672nm SII light reaches your sensor. It prevents star bloat from infrared (IR) light and eliminates gradients from nearby light pollution sources, resulting in a cleaner, higher-contrast image.

    Can I use the SVBONY SV227 filter for visual observing?

    No, this filter is not recommended for visual use. The 5nm bandpass is extremely restrictive and will make the view through an eyepiece far too dim to see anything. Narrowband filters like the SV227 are designed specifically for long-exposure astrophotography with sensitive monochrome or color cameras.

  • Filter Type SII (Sulfur-II) Filter
    Size 2-Inch
    Center Wavelength (CWL) 672nm
    Bandpass (FWHM) 5nm
    Peak Transmittance ≥90%
    Blocking ≥OD5 over 300-1000nm
    Clear Aperture 44mm
    Substrate Thickness 1.85mm
    Surface Quality 60/40
    Surface Parallelism 1/4λ
    Parallelism (Angle) 30"
    Thread M48x0.75
    Single Thread Yes
    Net Weight 12.5g / 0.44oz
  • SVBONY 1-Year Warranty