Focus Scientific

Astronomik Hydrogen Alpha (H-alpha) Narrowband 6nm CCD Filter (1.25\")

If you have to observe from light polluted sites (like most of us), imaging with narrowband emission line filters is the best way to take great images, as all kind of light pollution can be blocked very effectively! Normally, an H-alpha filter should be your first step into this amazing field of astrophotography. With a narrowband H-alpha filter you will be able to take deep and contrasty images even with very heavy light pollution or with the full moon high up in the sky! If you look at other astrophotos, an H-alpha is the best choice for all nebulae that glow red.

This H-alpha filter is suitable for imaging of Hydrogen nebulae from observation sites with light pollution and from dark sites as well. The contrast between an object glowing at 656nm and the background is increased enormously.

Due to the combination of the narrow bandwidth of 6nm and the high transmission of typically 96%, the filter gives you an enormous contrast boost, as all unwanted light from wavelengths other than 656nm is blocked, from UV up to IR. This results in an extremely dark background. The FWHM of 6nm is matched to give you optimal performance with CCD and CMOS sensors with a very low dark current. The 6nm filter is the best choice if you are observing from a heavily light polluted site or if you are imaging faint objects in star-crowded regions of the Milky Way.

The lower priced 12nm filters are the right choice if you own a typical DSLR or a CCD camera with a high dark current. The 12nm filters should be the first choice for cameras with an integrated guiding sensor, as you will have about twice as much stars compared to the 6nm filter.

This filter is not for solar observation.

Price does not include shipping from Germany, which is separate from the possible free shipping from us to you. You will be notified of these shipping charges prior to payment being taken.

Specifications

  • Guaranteed transmission of more than 90% at the H-alpha line (656 nm)
  • Typical Transmission of 96% at the H-alpha Line (656 nm)
  • Full-Width-Half Maximum (FWHM): 6nm
  • Perfect blocking of unwanted light from UV up to the IR
  • parfocal with all Astronomik filters
  • MFR coating technique: usable with all optics up to f/4
  • Thickness: 1mm
  • Not sensitive to moisture, scratch resistant, non-aging
  • opticaly polished substrate, striae-free and free of residual stresses
  • High quality storage box
  • Made in Germany