Baader Filters OIII CMOS f/2 Ultra-Highspeed 65x65mm (70941)

OIII filters are designed to allow only light with a wavelength of 501 nanometers to pass through. This corresponds to the spectral lines of doubly ionized oxygen, which are emitted by planetary nebulae and some emission nebulae. By blocking out other wavelengths, these filters enhance contrast, making faint nebulae visible while suppressing unwanted light.

Astrophotography is where these filters truly shine. They are best used with monochrome cameras, and for optimal results, images taken with OIII filters should be combined with those captured using H-alpha and SII filters. This combination creates high-contrast images that clearly depict faint nebulae in exceptional detail.

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): 65 x 65

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 essential for astrophotographers who want to isolate specific emissions from nebulae and produce stunning, high-contrast images of deep-sky objects.