Sulfur II Narrowband Filter

I was worried about keeping focus across my whole imaging rig, but this filter being parfocal with my other gear made swapping between SII and Ha bands seamless. The doublet at 671.6 and 673.1 nm really pulled out those wispy sulfur structures in the Bubble Nebula.

My first test image showed crisp, clean detail in the Sulfur II lines, and the parfocal design meant I didn't have to refocus between filters. It locks onto those 671.6 and 673.1 nm wavelengths exactly as described, giving me a much cleaner separation of the nebula’s structure than my older filter.

Finally got clear skies to test this SII filter, and the parfocal design meant no refocusing needed between exposures. The doublet lines at 671.6 and 673.1 nm really brought out the sulfur detail in the nebula.