Filter Size: 1.25" S-II Narrowband CCD Filter 8nm, 2" S-II Narrowband CCD Filter 8nm (BAA-2458430 and BAA-2458431)
CCD imagers will find the Baader Planetarium Narrowband S-II CCD Filter 8nm to deliver the absolute highest contrast deep sky images in H-Alpha, H-Beta, Oxygen III, and Sulfur-II, with the shortest exposures possible. Their ultra-narrow bandwidths have extremely high transmissions, while completely rejecting light pollution as well as the important blocking of longer wavelengths.
The high optical quality of the Baader narrowband filters guarantees no loss in sharpness or contrast. Each substrate is fine-optically polished plane parallel to deliver a smooth and accurate 1/4 wavefront over the entire surface. This special custom polishing operation sets Baader filters apart from the standard commercially precision polished filter substrates used by most other filter manufacturers.