Baader Filters OIII CMOS f/2 Ultra-Highspeed 50x50mm (70940)

OIII filters are specialized tools that allow only light with a wavelength of 501 nanometers to pass through. This wavelength corresponds to the spectral lines of doubly ionized oxygen, which are emitted by planetary nebulae and some emission nebulae. By blocking out other wavelengths, the filter enhances contrast, making faint nebulae visible for the first time while suppressing surrounding light.

Astrophotography Applications

These filters work best with monochrome cameras. For optimal results, images taken with OIII filters are often combined with those captured using H-alpha and SII filters. This combination produces high-contrast, detailed images that reveal faint nebulae clearly.

Specifications

    Central Wavelength (nm): 500.7
    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

OIII filters are indispensable for astrophotographers aiming to isolate specific emissions from nebulae and create stunning, high-contrast images of deep-sky objects.