Astrodon Nitrogen II (NII) 3nm Narrowband Filter - 31mm Unmounted
Astrodon
Nitrogen II (NII) Narrowband 3 nm Filter - 31mm Unmounted is a narrowband filter in 31mm for mono emission-line imaging.
imaging-filter midrange
Best Current Offer
Cloud Break Optics
Out of stock
Specifications
Filter
- Filter type
- Single-line narrowband filter
- Filter size
- 31 mm / Unmounted
Spectral
- Passbands
- NII 658.3 nm (3 nm)
- Band count
- 1 band
- Narrowest bandpass
- 3 nm
Use
- Camera use
- Mono astronomy cameras
Astrophotography Fit
Best for isolating emission lines with a mono camera and filter wheel.
Nitrogen II (NII) Narrowband 3 nm Filter - 31mm Unmounted is a midrange narrowband filter (31mm).
Best for isolating emission lines with a mono camera and filter wheel.
Choose filter size around the sensor diagonal, telescope speed, and filter-wheel or drawer geometry. Flats are still required; a filter can improve contrast, but it will not rescue tilt, bad focus, or poor calibration.
Best paired with
- Monochrome camera, matching filter wheel, and autofocus offsets
- Ha/OIII/SII emission nebula projects
- Long integrations with darks, flats, and careful star handling
Not recommended for
- Unmodified color cameras as the primary workflow
- Targets dominated by broadband continuum signal
- Users who want natural star color with minimal processing
Where To Buy
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| Retailer | Price | Availability | View Offer |
|---|---|---|---|
| Cloud Break Optics Cloud Break Optics | $682.00 | Out of stock Updated 5/15/2026 | View Offer - $682.00 |