Astromania IR / UV blocking filter - keeps your planetary images sharp Really sharp planetary images are only possible using an IR/UV blocking filter. This Astromania filter only allows the visible light between 400 and 680nm through. The UV and IR regions of the spectrum are completely blocked. CCD exposures of planets and stars - sharp images A CCD camera is not only sensitive to visible light but also to other wavelengths. Planets not only shine in visible light, but also in the infrared for example. But they are out of focus in the IR region. The Astromania filters only lets through the visible light, the light that is really 'wanted', meaning sharp planetary images. Blocking UV light The harmful UV rays that can contribute to cataracts are filtered out. The filter is also essential when using a Herschel wedge. Your eyes are valuable! - protect them with an Astromania UV/IR blocking filter. The advantages in a nutshell: only lets through visible light blocks the UV and IR range particularly useful for planetary imaging with webcams optically polished and coated continued in a robust 2" aluminium housing