The Baader Planetarium Oxygen III Nebula Filter delivers the absolute highest contrast deep sky images of many diffuse and planetary nebula. Baader Planetarium's premium Narrowband CCD passfilters are a must-have when it comes to excellent photography with modern CCD cameras. Providing the shortest exposures possible, the ultra-narrow bandwidths have extremely high transmission while completely rejecting light pollution and blocking longer wavelengths.
Delivering a smooth and accurate 1/4 wave wavefront over the entire surface, each substrate is fine-optically-polished delivering exceptional performance. The special custom polishing operation Baader executes on all Narrowband passfilters makes the difference compared to standard commercially-made polished filter substrates. In the production process for Baader Narrowband CCD passfilters, consideration of eliminating annoying reflections present in other narrowband astro-filters was a key component. In order to succeed in assuring freedom from reflections, Baader's production process required careful design and testing of the coating stacks. This research work resulted in the fine, high-quality Narrowband 8.5 nm O-III CCD Filter offered here.