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• Advanced Dual-Band Filter Technology: The Altair Dual-Band ULTRA Sii/Oii is a cutting-edge narrowband filter with a tight 6nm FWHM Bandpass, designed for enhancing nebula imaging.
• Effective Light Pollution Suppression: Incorporates Altair V2 coatings, highly effective against LED light pollution, offering deep blocking factors of OD>6 below 440nm and OD5 in the visual range.
• Exceptional Transmission Rates: Demonstrates impressive transmission rates of 93% for both Oiii (6nm bandwidth) and Sii (5.5nm bandwidth), with precise tolerances of 0.5nm and 0.5%.
• Ideal for Diverse Imaging Conditions: Perfect for imaging in moonlight, light pollution, or dark-sky conditions, providing total channel control in narrowband-style imaging.
• Certified Individual Testing: Each filter undergoes individual spectrographic testing with 0.1nm true resolution, ensuring authenticity and superior performance, unlike generic test reports from other brands.
• DualBand Ha/Oiii Emission Suppression: Transmits only Sii and Oiii light from emission nebulae, effectively suppressing unwanted light, ideal for narrowband Bi-Colour imaging.
• Versatile Imaging Capabilities: Capture key emission nebulae bands simultaneously while suppressing extraneous light. Compatible with color CMOS cameras for varied imaging scenarios.
• Increased Data Acquisition: Acquire more data efficiently, expanding your imaging window, even in challenging conditions like summer nights.
• Complementary Use with Ha Oiii Filter: Combine with Ha Oiii version for doubled Oiii data capture per session, enabling true SHO Hubble style imaging with color cameras.
• Steep Bandpass for Maximum Contrast: Features a steep 6nm bandpass for Oiii and 5.5nm for Sii, enhancing contrast in extreme light pollution conditions.
• Halo Suppression and Compatibility: No reported halos in testing, suitable for both One Shot Colour (OSC) CMOS and mono cameras.
• Optimized for Various Telescopes: Performs best at F4.8 or slower focal ratios, but can be used up to F3.6 with minimal contrast impact.
• Standard Filter Thread and Specifications: Fits standard M48x0.75mm thread, compatible with various holders and wheels. Specifications include two bands, Oiii and Sii, with 93% transmission and OD5 blocking.
• Frequently Asked Questions: Explains the functionality of OSC Narrowband filters, compatibility with different cameras, and the concept of DualBand filtering.
• Availability Note: High demand may lead to temporary suspension of orders to maintain production quality. Specifications and prices are subject to change without notice.

Safety Reminder: Always ensure proper solar viewing safety measures when using filters for solar imaging.

Specifications

HA/Oiii

• *1st band, Oiii CWL 500.7nm FWHM 6nm ~0.5nm tolerance , T% 93% 0.5% Tolerance.
• *2nd band, Ha CWL 656.28nm FWHM 5.5nm ~0.5nm tolerance, T% 93% 0.5% Tolerance.
• OD4/5 Blocking (0.01%~0.001%) over the majority of unwanted wavelengths
• 1.85mm thick optical glass with 30 arc sec parallelism. Parfocal with other Altair filters.
• Si02 "hard" overcoat with UVIR Block and Anti-Reflection Coating for durability.

Oiii/Sii

• *1st band, Oiii CWL 500.7nm FWHM 6nm ~0.5nm tolerance , T% 93% 0.5% Tolerance.
• *2nd band, Sii CWL 671.6nm FWHM 5.5nm ~0.5nm tolerance, T% 93% 0.5% Tolerance.
• OD5 Blocking (0.001%) over unwanted visual wavelengths
• 1.85mm thick optical glass with 30 arc sec parallelism. Parfocal with other Altair filters.
• Si02 "hard" overcoat with UVIR Block and Anti-Reflection Coating for durability.