Askar Filters Colour Magic OIII 3nm 2" (87816)

The ColourMagic 3 nm Narrowband Filter features an extremely narrow bandwidth combined with excellent light transmission, allowing the capture of high-contrast, low-noise deep-sky images even under challenging conditions such as urban light pollution, atmospheric airglow, or other sources of stray light.

This performance makes faint nebular structures and subtle stellar details, which are often difficult to reveal, clearly visible. The filter also incorporates an optimized optical design for improved halo control, resulting in higher image quality and greater expressive power in astrophotography.

OIII filters allow only light with a wavelength of approximately 501 nanometres to pass through. This wavelength corresponds to the emission lines of doubly ionized oxygen, which are produced by planetary nebulae and certain emission nebulae. These objects remain visible while most other wavelengths are blocked, significantly increasing contrast and allowing faint nebulae to stand out for the first time.

Astrophotography use
These filters are best used with monochrome cameras. For optimal results, images captured with an OIII filter should be combined with exposures taken using H-alpha and SII filters. This technique produces high-contrast images that clearly show fine nebular detail.

Specifications

• Quantity: 1 piece

• Central wavelength: 500.7 nm

• Half-value bandwidth: 3.7 nm

• Filter thickness: 1.85 mm

• Mount size: 2-inch

• Transmission: 85%

• Mount material: Aluminium

• Optical coating: Multi-layer

General information

• Type: Filter

• Design: Narrowband line filter

• Series: Colour Magic 3 nm

• Connection to telescope: 2-inch

Areas of application

• Suitable for photography: Yes

• Suitable for visual observation: No

• Twin stars: No

• Moon and planets: No

• Nebulae and galaxies: Yes