Colour Magic 2″ Duo-Narrowband D1 (Hα+OIII)

Askar's Duo-Narrowband D1 filter: precision for astrophotography

Askar's Duo-Narrowband D1 filter is specially designed for astrophotographers seeking to capture the finest details of nebulae and other deep-sky objects, even in the presence of light pollution. This 2" filter, calibrated for Ha and OIII bands, delivers outstanding image quality, accentuating contrast and reducing unwanted light interference.

With a peak transmission of 85 % at its central wavelengths (500.7 nm for OIII and 656.6 nm for Ha), the D1 filter captures the specific emissions of nebulae, while effectively blocking out other light sources. This level of precision is ideal for astrophotographers who want to highlight the details of stars and nebula structures, offering a sharp, high-contrast image even in urban areas or with strong ambient lighting.

The D1 filter is distinguished by its narrow bandwidth: 6.5 nm for OIII and 8.5 nm for Ha. This reduces light interference and maximizes the clarity of the details captured in celestial objects. The filter's narrow bandwidth makes it particularly effective in environments with high levels of light pollution, enabling images of unrivalled detail and precision to be obtained.

With a thickness of 1.85 mm and an OD5 barrier property over a wide range of wavelengths (200 to 1100 nm), the D1 filter is robust and reliable. Its 60/40 surface finish guarantees excellent optical quality, ensuring that every detail of celestial objects is accurately captured. This makes the filter a perfect choice for those seeking optimum image quality in all conditions.

Although designed for specific use in conditions of high light pollution, Askar's D1 filter is versatile and can also be used with fast telescopes. This makes it suitable for a wide variety of astrophotography configurations and instruments, enabling users to explore the nuances of the deep sky without compromise.

All in all, Askar's Duo-Narrowband D1 filter is an exceptional choice for astrophotographers wishing to capture images of impeccable quality, with optimized sharpness and contrast in the Ha and OIII bands. Whether you're an amateur or a professional, this filter will enable you to reveal the beauty of nebulae and stars like never before, offering a clear, detailed view of the wonders of our universe.

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 and duo-narrowband 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.