The O III 2 "filter has the best effects of all nebulae filters, especially under very light-polluted skies. Ideally suited for CCD photography due to its unsurpassed contrast. No picture degradation can be seen even at the highest magnifications. It has the same ultra-hard, extremely durable and vacuum coated dielectric coatings as those used in the UHC-S filter. The Baader O-III filter effectively blocks the entire visual spectrum except for the O-III spectral line, eliminating annoying colored halo around stars that often appear in O-III filters produced with less advanced coating technologies.
• diameter of the housing: 2 "
• transmission: 92%