Astronomik H-alpha 12 nm 2" — narrowband imaging filter (MFR) The Astronomik H-alpha 12 nm filter isolates the 656 nm hydrogen-alpha line for imaging emission nebulae from light-polluted and dark sites alike. It blocks sodium and mercury-vapour lamp lines, all lines of natural airglow and most moonlight, giving deep, high-contrast images.
Manufacturer model: Astronomik H-alpha 12nm 2" (M48), MFR, 10212200 · Specifications checked against manufacturer data on 2026-11-03
The Astronomik H-alpha 12 nm filter isolates the 656 nm hydrogen-alpha line for imaging emission nebulae from light-polluted and dark sites alike. It blocks sodium and mercury-vapour lamp lines, all lines of natural airglow and most moonlight, giving deep, high-contrast images.
Astronomik developed its 12 nm filters for typical DSLR cameras with CMOS sensors and for CCD cameras with normal or high dark current. Compared with 6 nm versions they show more stars, which makes them the preferred choice for cameras with an integrated or dual guiding sensor.
This standard MFR version can be used with instruments from f/3 upwards without significant performance loss. For faster optics, Astronomik offers a separate MaxFR version (10250200), rated from f/1.7 to f/6. Every Astronomik narrowband filter is measured on a PerkinElmer spectrophotometer, and the box label shows that filter's own spectral data.
This filter must not be used for solar observation.
| Line | H-alpha, 656 nm |
|---|---|
| Bandwidth (FWHM) | 12 nm |
| Transmission at 656 nm | Guaranteed over 90%; typically 96% |
| Coating | Astronomik MFR |
| Focal ratio range | f/3 to f/∞ without significant performance loss |
| Blocking | UV to IR outside the passband |
| Manufacturer code | 10212200 |
|---|---|
| Format | 2-inch cell, M48 × 0.75 thread |
| Glass thickness | 1 mm |
| Parfocal | With other Astronomik filters |
| Made in | Germany |
Astronomik H-alpha 12nm 2" product page
Standard MFR 12 nm (10212200, f/3 and slower), not MaxFR (10250200). Not for solar use.
| Guaranteed transmission (%) | >90 |
|---|
Data sheet
Specific References
Astronomik H-alpha 12 nm 2" — narrowband imaging filter (MFR) The Astronomik H-alpha 12 nm filter isolates the 656 nm hydrogen-alpha line for imaging emission nebulae from light-polluted and dark sites alike. It blocks sodium and mercury-vapour lamp lines, all lines of natural airglow and most moonlight, giving deep, high-contrast images.
Manufacturer model: Astronomik H-alpha 12nm 2" (M48), MFR, 10212200 · Specifications checked against manufacturer data on 2026-11-03
