Astronomik 1.25" 12nm H-alpha CCD filter

Astronomik H-alpha 12 nm 1.25" — 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.

Why 12 nm

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. Under dark skies, image background is usually limited by sensor dark current rather than light pollution, so a narrower band does not necessarily reveal more detail.

MFR coating

This standard MFR version can be used with instruments from f/3 upwards without significant performance loss. For faster optics, such as RASA or Epsilon astrographs, Astronomik offers a separate MaxFR version, 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.

Optical

Physical

Manufacturer documentation

Astronomik H-alpha filter range

Compatibility notes

Standard MFR 12 nm (f/3 and slower), not MaxFR (10250125, f/1.7–f/6) and not 6 nm/4 nm. MFR article number for 1.25-inch not shown in sources reviewed. Not for solar use.

Additional specifications