Astrodon Oxygen III (OIII) 5nm Narrowband Filter - 31mm Unmounted
Astrodon
Oxygen-III (OIII) Narrowband Filter - 31mm Unmounted / 5nm 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
- OIII 500.7 nm (5 nm)
- Band count
- 1 band
- Narrowest bandpass
- 5 nm
Use
- Camera use
- Mono astronomy cameras
Astrophotography Fit
Best for isolating emission lines with a mono camera and filter wheel.
Oxygen-III (OIII) Narrowband Filter - 31mm Unmounted / 5nm 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
Some links on this page are affiliate links. Prices and availability are pulled automatically from each retailer and updated daily.
| Retailer | Price | Availability | View Offer |
|---|---|---|---|
| Cloud Break Optics Cloud Break Optics | $380.00 | Out of stock Updated 5/14/2026 | View Offer - $380.00 |