Astro Duo-Narrowband (Duo-NB) Filter

Astrophotography is all about capturing light from billions of years ago. As avid astrophotographers, the STC team thought long and hard about how to create a filter to capture ultra-high contrast nebulae images — even with urban light pollution.

STC is the FIRST company in the world to create a dual-narrowband pass in ONE filter for deep sky astrophotographers. As experienced astrophotographers painfully know, shooting multiple images using two different filters would be necessary. Our Duo-Narrowband filter cuts the time required in half! Many have tried to copy our technology. None are successful in delivering our level of optical quality!

STC's Astro Duo-Narrowband filter is specifically engineered to capture 7–12nm bandpass for H-Alpha, and Oxygen III nebula emission lines found in gaseous nebulae. With a transmission rating of greater than 85%, this is an astrophotographers' dream filter.

Highlights

• Ideal for photographing emission nebulae with an urban or suburban foreground (Bortle scale 3–9).
• Enables high-contrast natural color images.
• Easy to use with ordinary digital or cooled CCD cameras.
• We also have clip filter versions for Canon, Nikon, Sony, Fujifilm, Pentax, Olympus, Panasonic, Blackmagic Pocket Cinema Camera, and Z Cam E-2.

Features

• Blocks urban light pollution. We coat the filter using ion beam-assisted deposition (IBAD).
• 1mm Schott B270 optical glass prevents fogging by quickly absorbing and dissipating heat.
• Double-sided anti-smudge nano-coating is hydrophobic stopping moisture and mold.
• Anti-static coating keeps dust and fibers away.
• Super flat surface so you can capture clear images even when shooting at 8K and with 1200mm high-magnification telescope lens.
• Anodized aluminum eliminates surface reflection to avoid glare and ghost images.
• Aluminum rim treated with Teflon and black matte finish and easy to remove.
• Can be used with STC's Astro AdapterM48-M56 astronomical lens adapter ring, 0.75mm pitch (sold separately).
• Covered by the world's first global filter warranty and repair service.

Frequently Asked Questions

What makes the Duo-NB filter unique?
STC is the first company in the world to create a dual-narrowband pass (H-Alpha and OIII) in a single filter, cutting the time required for deep sky astrophotography in half compared to using two separate filters.

What Bortle scale is this filter designed for?
The Duo-NB filter is ideal for Bortle scale 3–9, making it suitable for both suburban and urban environments with significant light pollution.

What sizes are available?
Available in 1.25", 2" (48mm) rear-threaded, 2" (48mm) front and rear threaded, and 52mm (above two weeks lead time).

What cameras is this compatible with?
Compatible with ordinary digital cameras and cooled CCD cameras. Clip filter versions are also available for Canon, Nikon, Sony, Fujifilm, Pentax, Olympus, Panasonic, Blackmagic Pocket Cinema Camera, and Z Cam E-2.

What focal length is recommended?
Recommended for telephoto lenses of focal length 60mm and greater. For wider lenses, consider STC's clip filters (recommended for focal length 14mm full-frame and above).