Baader Narrowband H-alpha Filter CMOS f/2 Highspeed 2 inch

Baader Narrowband H-alpha Filter CMOS f/2 Highspeed 2 inch: narrowband for extremely fast optics

Hydrogen is the most common element in the universe, and the H-alpha line is therefore the most important emission line for nebula photography. This filter isolates that line with a half-width of 6.5 nm. The f/2 Highspeed version is specially designed for extremely fast optics: the passband is pre-shifted so that the filter continues to operate at the correct wavelength at aperture ratios from f/3.4 to f/1.8.

In fast optical systems like a Celestron RASA or Hyperstar, light strikes the filter at steep angles. This causes the passband of a standard filter to shift, resulting in signal loss. The Highspeed series compensates for this, maintaining full transmission at the H-alpha line.

CMOS-optimized

The filters are optimized for modern CMOS cameras: the 6.5 nm full-width at half-maximum has been chosen for balanced exposures across the channels, and the Reflex-Blocker hard coating suppresses halos around bright stars. Blackened edges and the Life-Coat edge sealing make the coating resistant to years of use.

What you use this filter for

This filter is made for emission nebulae like the North America Nebula, planetary nebulae, and supernova remnants. Due to the narrow passband, the sky background becomes deeply dark, even under light-polluted skies or moonlight, and the deep red nebular structure is highlighted to the maximum.

Featured accessories

Combine this filter with the other two lines in the series (H-alpha, OIII, and SII) for complete narrowband or Hubble palette captures.

For whom yes and for whom no

• ✓ Astrophotographers with fast optics (f/1.8 to f/3.4) such as RASA and Hyperstar systems
• ✓ Who wants to shoot narrowband under a light-polluted sky
• Owners of slower telescopes (f/4 and slower): the standard Baader Narrowband series without preshift is the right choice.

Specifications

You can find more accessories for this brand at the Baader brand page.