Baader Filters OIII CMOS f/2 Ultra-Highspeed 1.25" (70935)

OIII filters 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 all other light, these filters enhance contrast and make faint nebulae visible for the first time.

Astrophotography
These filters are best suited for use with monochrome cameras. For optimal results, images taken with OIII filters should be combined with those captured using H-alpha and SII filters. This combination produces high-contrast images that clearly depict faint nebulae.

Specifications

    Capacity
        Central wavelength (nm): 500.7
        Half-value width (nm): 4
    Frame
        Size: 1.25"
        Mount material: Aluminium
        Coating: Reflex-Blocker™
    Connection to Telescope
        Size: 1.25"
    Compatibility
        Suitable for f/3.4 - f/1.8 systems
        Filter thickness (mm): 2
    General Information
        Type: Filters
        Build: Line filter
        Series: f/2 Ultra-Highspeed
    Applications
        Useful for photographs: Yes
        Visually useful: No
        Twin stars: No
        Moon & planets: No
        Nebulae & galaxies: Yes

These OIII filters are essential for astrophotographers aiming to capture detailed and high-contrast images of nebulae, especially when combined with other narrowband filters like H-alpha and SII.