The Baader C2 Swan-Band Comet Filter 15 nm (2") is a visual advantage for astrophotographers when observing and photographing comets - if you want to get the most contrasty images optimized for CMOS - but also excellent on CCD.
The filters block the OIII wavelength range at 501nm and below, while passing the excited carbon ion wavelengths at 511 and 514nm. At other "unwanted" wavelengths, they "cut off" the light completely. This property helps to distinguish mainly gaseous comets from dust-based comets, with the gas plume contrasting nicely in the visible range.
The excellent glass material and machining of the filters promise excellent contrast and sharpness. The coatings are applied to the glass material using state-of-the-art tools, which guarantee an ideal transmission range.
The anti-reflective Front-Reflex-Blocker™ coatings contribute to excellent imaging, and the surfaces have also been treated with a Life-Coat™ treatment that makes the glass material scratch-resistant.