Baader Filters OIII CMOS Ultra-Narrowband 1.25" (70879)

The OIII filters allow only light with a wavelength of 501 nanometers to pass through, corresponding to the spectrum lines of double-ionized oxygen. These lines are emitted by planetary nebulae and some emission nebulae, ensuring these objects remain visible while blocking out other light sources. This filtering effect enhances contrast and makes faint nebulae visible for the first time.

For astrophotography, OIII filters work best with monochrome cameras. To produce high-contrast images that clearly depict faint nebulae, combine images taken with OIII filters alongside those captured using H-alpha and SII filters.

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"
Aperture Ratio Range: f/10 to f/3.5

Filter Thickness
Thickness (mm): 2

General Information
Type: Filters
Build Type: Line filter
Series: Ultra-Narrowband

Area of Application
Useful for Photographs: Yes
Visually Useful: No
Twin Stars: No
Moon & Planets: No
Nebulae & Galaxies: Yes