Omegon pro SII filter - for the astrophotography of SII regionsThis type of interference filter lets you increase the contrast when photographing deep sky objects. The object stands out better against the night sky background, letting you see detail that was not apparent before. The SII Omegon pro filter has been specifically designed for the astrophotography of nebulae using CCD and DSRL type astronomy cameras.Many planetary and emission nebulae will show significant additional detail when imaged in the first ionized sulphur frequency at 672nm. This filter allows this range of interest through, but blocks stray light and artificial lighting.With a small 'peak width at half height' of 12nm, and high transmission, this filter will take you into the realm of high-end astrophotography. You will be able to create excellent deep-sky images, even from big cities. And combined with OIII- and H-alpha filters, your images will be real eye-catchers!