Baader Filters SII CMOS f/2 Ultra-Highspeed 2" (70945)

SII filters are narrowband filters designed for nebula photography, passing light at a wavelength of 672nm with a bandpass of 3nm. They are ideal for capturing most emission nebulae, planetary nebulae, and supernova remnants.

If you want to replicate the iconic look of Hubble Space Telescope (HST) images, such as the famous “Pillars of Creation” in the Eagle Nebula (Messier 16), the SII filter is a key addition to your astrophotography setup after H-alpha and OIII filters. Like the H-alpha filter, the SII filter is a deep red filter near 672nm. Together, H-alpha, OIII, and SII filters enable tri-color narrowband imaging that provides the distinct Hubble-like appearance for many emission nebulae. These filters can also be used during moonlit nights, ensuring your astrophotography sessions continue uninterrupted.

Specifications:

    Central Wavelength (nm): 671.7
    Half-Value Width (nm): 4
    Frame Type: 2"
    Mount Material: Aluminium
    Coating: Reflex-Blocker™
    Connection (to Telescope): 2"
    Filter Thickness (mm): 2

Compatibility and Applications:

    Appropriate for f/ratio: f/3.4 - f/1.8
    Type: Line filter
    Series: f/2 Ultra-Highspeed

Applications:

    Useful for photographs: Yes
    Visually useful: No
    Twin stars, Moon & Planets: Not suitable
    Nebulae & Galaxies: Ideal

The SII filter is an essential tool for astrophotographers looking to create stunning tri-color narrowband images with high contrast and exceptional detail while minimizing interference from light pollution or moonlight.