CHF 559
Part no. FILTER-0003
In stock with supplier
Askar's Duo-Narrowband D1 and D2 pack is specially designed for the most demanding astrophotographers, looking to capture detailed, high-contrast images of deep-sky objects, with optimum flexibility according to observing conditions. By combining the D1 (Ha + OIII) and D2 (OIII + SII) filters, this pack lets you cover a wide range of wavelength bands, offering exceptional imaging potential, even in environments with high light pollution.
The D1 filter captures emissions from the Ha (Hydrogen Alpha) and OIII (Oxygen III) bands, wavelengths essential for revealing the fine structures of nebulae and other celestial objects. With a narrow bandwidth of 6.5 nm for OIII and 8.5 nm for Ha, and a peak transmission of 85 %, the D1 is ideal for capturing sharp, high-contrast images in urban environments where light pollution is high. This filter is designed to maximize the detail and contrast of nebulae, delivering images of remarkable clarity.
The D2 filter, also known as Super D, is dedicated to OIII and SII (Sulfur II) band emissions. With a high transmission of 85 % and a narrow bandwidth of 6.5 nm for OIII and 8.5 nm for SII, it captures the details of nebulae at these specific wavelengths, effectively blocking light pollution sources. The D2 stands out for its "Super" halo control, which minimizes halos around stars and thus improves image sharpness and contrast, even in difficult conditions. Its compatibility with high-speed telescopes up to f/1.9 makes it an extremely versatile filter.
By combining the D1 and D2 filters, this pack offers complete coverage of the three key bands (Ha, OIII, and SII), providing unrivalled flexibility for your astrophotography sessions. Whether you want to capture the rich details of nebulae in Ha and OIII with the D1, or accentuate contrasts and reveal subtle structures in OIII and SII with the D2, this filter duo lets you compose your images to suit your needs and observing conditions.
This pack is ideal for astrophotographers who want to explore the full extent of nebula emissions and celestial objects, while obtaining professional-quality images. With Askar's Duo-Narrowband D1 and D2 pack, you have at your fingertips the tools you need to capture deep, detailed images, free from unwanted light pollution and offering unrivalled rendering quality.
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.
