• Chroma SII 3nm Narrowband filter is designed primarily for astrophotography, specifically targeting deep sky emission sources emitting the SII 670nm spectral line.
• Enhancing the contrast of the SII signal and effectively blocking extraneous light beyond the specific SII wavelength with its extremely narrow 3nm bandpass.
• This filter is well-suited for mid-range to slow focal ratio optical systems, as it maintains a minimal Center Wavelength shift and significantly reduces the risk of light loss compared to lower-quality filters.
• This configuration is a 2" mounted version.

The Chroma SII 3nm Narrowband filter is a geared mainly for astrophotography of deep sky emission sources of the SII 670nm spectral line by optimizing the narrow bandpass of 3nm. By having a bandpass this narrow, it boosts contrast of the SII signal while removing far more light from beyond the specific SII wavelength.

This version of the SII 3nm filter works well for any mid range to slow focal ratio.