Askar Filters Colour Magic H-alpha SII OIII 3nm 2" (87817)

The ColourMagic 3 nm Narrowband Filter set features an extremely narrow bandwidth combined with excellent light transmission, allowing the capture of high-contrast, low-noise deep-sky images even in environments affected by urban light pollution, atmospheric airglow, or other stray light sources.

This performance makes faint nebular structures and subtle stellar details, which are often difficult to reveal, clearly visible. In addition, the ColourMagic filters use an optimized optical design for effective halo control, resulting in higher image quality and greater expressive power in astrophotography.

H-alpha performance
The H-alpha filter is ideal for imaging hydrogen emission nebulae, both from light-polluted locations and from dark-sky sites. It significantly enhances contrast between objects emitting in H-alpha light and the background sky, allowing fine nebular structures to stand out clearly.

SII filter performance
The SII narrowband filter transmits light from ionized sulfur atoms at wavelengths of 671.7 and 673.1 nanometres. These emission lines are characteristic of many planetary nebulae, emission nebulae, and supernova remnants, making this filter particularly useful for revealing faint and complex structures.

OIII filter performance
The OIII filter allows only light at a wavelength of approximately 501 nanometres to pass through. This corresponds to the emission lines of doubly ionized oxygen, which are produced by planetary nebulae and certain emission nebulae. By blocking most other wavelengths, the filter greatly increases contrast and makes faint nebulae visible for the first time.

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

Specifications

• Quantity: 3 filters

• Central wavelengths: 500.7 nm, 656.6 nm, 672 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: Filters

• Design: Narrowband line filters

• 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