Baader Filters f/2 Ultra-Highspeed SII CMOS 50.4mm (70946)

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

If you aspire 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 an essential addition to your astrophotography toolkit after H-alpha and OIII filters. Similar to 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 characteristic Hubble-like appearance for many emission nebulae. These filters can also be used during moonlit nights, allowing you to continue imaging without interruption.

Specifications:

    Central Wavelength (nm): 671.7
    Half-Value Width (nm): 4
    Frame Type: Ring
    Mount Material: Aluminium
    Coating: Reflex-Blocker™
    Filter Thickness (mm): 2
    Filter Size (mm): 50.4

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 indispensable tool for astrophotographers aiming to create stunning tri-color narrowband images with exceptional detail and contrast while minimizing interference from light pollution or moonlight.