ZWO SII 7nm 36mm Filter
ZWO SII 7nm CCD Imaging Filter - 36mm
Sulfur is in the deep red of the spectrum near 672 nm. When combined with H-a and OIII (Hydrogen-Alpha and Oxygen III, or double ionized oxygen) SII will produce images with colors that are reminiscent of those taken by the Hubble Space Telescope.
The ZWO SII 7nm 36mm Filter is unmounted. ZWO narrowband filters are fine-optically polished to reach an accuracy of 1/4 wave. Their performance is further enhanced by multiple layers of anti-reflection coatings.