Baader Filters OIII CMOS f/3 Ultra-Highspeed-Filter 31mm (75578)

OIII filters allow light with a wavelength of 501 nanometers to pass through, corresponding to the spectral lines of doubly ionized oxygen. These lines are emitted by planetary nebulae and some emission nebulae. By blocking other wavelengths, the filter enhances contrast and makes faint nebulae visible for the first time.

Astrophotography applications benefit greatly from OIII filters, which are best used with monochrome cameras. For optimal results, images captured with OIII filters should be combined with those taken using H-alpha and SII filters. This combination creates high-contrast images that reveal faint nebulae in exceptional detail.

Specifications:

    Central Wavelength (nm): 500.7
    Half-Value Width (nm): 4
    Frame Type: Ring
    Mount Material: Aluminium
    Coating: Reflex-Blocker™
    Filter Thickness (mm): 2
    Filter Size (mm): 31

Compatibility and Applications:

    Appropriate for f/ratio: f/3.4 - f/2.3
    Type: Line filter
    Series: f/3 Ultra-Highspeed

Applications:

    Useful for photographs: Yes
    Visually useful: No
    Nebulae & Galaxies: Yes
    Moon & Planets: No

These OIII filters are indispensable for astrophotographers aiming to isolate oxygen emissions and produce high-contrast, detailed images of nebulae while reducing interference from surrounding light sources.