Baader Filters SII CMOS f/2 Highspeed 36mm (70923)

The narrowband S-II 7nm filter is specifically designed for nebula photography. It transmits light at a wavelength of 672nm with a bandpass of 3nm. This filter is ideal for capturing most emission nebulae, planetary nebulae, and supernova remnants.

If you're aiming to replicate the iconic look of Hubble Space Telescope (HST) images, such as the "Pillars of Creation" in the Eagle Nebula (Messier 16), the SII filter is an excellent addition to your collection after H-alpha (H-a) and OIII filters. Similar to the H-a filter, the SII filter operates in the deep red spectrum near 672nm. Together, H-a, OIII, and SII filters enable tri-color narrowband imaging, which can even be done under moonlit skies, ensuring your equipment remains productive regardless of lunar phases.

Specifications

    Capacity
        Central wavelength (nm): 671.7
        Half-value width (nm): 6.5
    Frame
        Mount material: Aluminium
        Coating: Reflex-Blocker™
    Compatibility
        Suitable for f/3.4 - f/1.8 systems
        Filter thickness (mm): 2
        Filter size (mm): 36
    General Information
        Type: Filters
        Build: Line filter
        Series: f/2 Highspeed
    Applications
        Useful for photographs: Yes
        Visually useful: No
        Twin stars: No
        Moon & planets: No
        Nebulae & galaxies: Yes

This filter is an essential tool for astrophotographers seeking to capture stunning details in emission nebulae and achieve that distinct "Hubble look."