Baader Filters SII CMOS f/2 Ultra-Highspeed 50x50mm (70947)

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

If you want to achieve 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 crucial addition to your astrophotography collection 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 delivers the distinctive Hubble-like appearance for many emission nebulae. These filters can also be used during moonlit nights, ensuring your imaging sessions are not interrupted by lunar brightness.

Specifications:

    Central Wavelength (nm): 671.7
    Half-Value Width (nm): 4
    Frame Type: Frames
    Mount Material: Aluminium
    Coating: Reflex-Blocker™
    Filter Thickness (mm): 2
    Filter Size (mm): 50 x 50

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 aiming to produce stunning tri-color narrowband images with exceptional detail and contrast while minimizing interference from light pollution or moonlight.