Colour Magic 2″ Duo-Narrowband D2 (SII+OIII)

Askar's Duo-Narrowband D2 (Super D) Filter: the essential tool for precision astrophotography

Askar's ColourMagic Super D2 Duo-narrowband filter is a technological breakthrough in astrophotography, designed specifically to capture the beauty of the deep sky with unrivalled precision. This 2-inch filter, optimized for OIII and SII band emissions, delivers outstanding images of nebulae and other celestial objects, even in conditions of high light pollution.

With a peak transmission of 85 % at its central wavelengths (500.7 nm for OIII and 672 nm for SII), the D2 filter is designed to maximize visible detail in your photos, accentuating contrasts and blocking unwanted light sources. Its unique "Super" halo control effectively eliminates halos around stars, revealing subtle details and enhancing the sharpness of your images. This level of precision is particularly appreciated by astrophotographers who want to capture the nuances and textures of nebulae.

The D2 filter is distinguished by its narrow bandwidth: 6.5 nm for OIII and 8.5 nm for SII, making it particularly well-suited to urban or light-polluted environments. This narrow bandwidth effectively isolates nebula signals, while blocking stray light sources, delivering sharper, higher-contrast images.

With a thickness of 1.85 mm and an OD5 barrier property over a wide range of wavelengths (200 to 1100 nm), the D2 filter is not only tough but also highly efficient. Its 60/40 surface finish guarantees impeccable optical quality, while its 30″ parallelism makes it an ideal choice for the most demanding observers and photographers.

Although not specifically designed for very high-speed telescopes, the Super D2 filter has proven its compatibility with high-speed telescopes up to f/1.9, making it a versatile, high-performance tool for capturing detailed images, even with high-performance instruments.

In short, Askar's Duo-narrowband D2 (Super D) filter is the tool of choice for passionate and demanding astrophotographers who want to capture celestial objects in all their glory, with uncompromising sharpness and contrast. Thanks to its innovative design and high performance, it lets you explore and capture the depths of the sky like never before.

ColourMagic Super D duo-narrowband filters for astrophotography: advanced tools for capturing the beauty of the deep sky

Askar ColourMagic Super D duo-narrowband filters are professional astrophotography tools specially designed to enhance the quality of deep-sky images. Whether you're using a color or monochrome camera, these filters offer exceptional performance, enabling you to capture precise details in specific wavelength bands. By capturing the Ha, OIII and SII bands, these filters reveal nebula features that are invisible to the naked eye and difficult to capture without specialized equipment. Here's a detailed look at each filter and the unique features they provide.

The duo-band "C" and duo-narrowband "D" filter range

1. Duo-band C1 filter (2")
- FWHM: OIII at 35 nm ± 5 nm, Ha at 15 nm ± 3 nm
- Center wavelength (CWL): 500.7 nm and 656.6 nm
- Peak transmission: 90 %
- Thickness: 2 ± 0.05 mm
- Barrier properties: OD3 from 200 to 1000 nm
- Surface finish: 60/40
This filter is ideal for astrophotography enthusiasts looking for a versatile solution for capturing both Ha and OIII emissions. With a transmission of 90 %, it guarantees clear, bright capture of nebulae.

2. Duo-band C2 filter (2")
- FWHM: OIII at 35 nm ± 5 nm, SII at 15 nm ± 3 nm
- Center wavelength (CWL): 500.7 nm and 672 nm
- Peak transmission: 90 %
- Thickness: 2 ± 0.05 mm
- Barrier properties: OD3 from 200 to 1000 nm
- Surface finish: 60/40
This filter is an excellent option for those wishing to capture SII emissions in addition to OIII. The combination of OIII and SII bands provides high-resolution images of nebulae with excellent clarity.

3. Duo-narrowband D1 (2") filter
- Width at half maximum (FWHM): OIII at 6.5 nm ± 0.5 nm, Ha at 8.5 nm ± 0.5 nm
- Center wavelength (CWL): 500.7 nm and 656.6 nm
- Peak transmission: 85 %
- Thickness: 1.85 ± 0.05 mm
- Barrier property: ≥OD5 from 200 to 1100 nm
- Surface finish: 60/40
This filter offers a narrower bandwidth, ideal for users looking to enhance the contrast of celestial objects while blocking light pollution sources. The narrow OIII and Ha bandwidths are particularly useful for urban environments where light pollution is intense.

4. Duo-narrowband D2 (2") filter (Super D)
- FWHM: OIII at 6.5 nm ± 0.5 nm, SII at 8.5 nm ± 0.5 nm
- Center wavelength (CWL): 500.7 nm and 672 nm
- Peak transmission: 85 %
- Thickness: 1.85 ± 0.05 mm
- Barrier property: ≥OD5 from 200 to 1100 nm
- Surface finish: 60/40
- Parallelism: 30″
The Super D2 Duo-narrowband filter, Askar's latest innovation, is designed for high-precision astrophotography. Featuring "Super" halo control capability, it dramatically improves the contrast of your images and eliminates unwanted halos around stars. This filter is optimized for optimum performance, even with fast telescopes up to f/1.9, delivering clear, detailed images of nebulae by capturing only specific SII and OIII band emissions.

Comparison of Askar duo-band and duo-narrowband filters
Duo-band filters C1 and C2 are ideal for those who want maximum light in less polluted environments, with high peak transmission (90 %) and wide band FWHM (35 nm for OIII). These filters are versatile and ideal for vibrantly colored nebula shots, but they let through a little more light, which can be a disadvantage in areas of high light pollution.

In contrast, duo-narrowband filters D1 and D2 (Super D) are designed for more selective image capture in conditions of higher light pollution. Their narrow bandwidth (6.5 nm for OIII, 8.5 nm for Ha or SII) and OD5 barrier effectively block unwanted signals, guaranteeing images of exceptional clarity and contrast. The Super D (D2) version also features "Super" halo control, minimizing light halos around stars and offering 30″ parallelism, ideal for professional users.

So, depending on your needs and observing environment, duo-band filters offer great flexibility for capturing luminous nebulae, while duo-narrowband filters, particularly the Super D2 model, are perfect choices for demanding astrophotographers looking for optimum detail even in light-polluted environments.