The Optololong L-eXtreme Narrowband Filter is specially designed for use with colour astronomy cameras and DSLRs. It is essentially two narrow-band filters in one: it has one passband optimized for the H-alpha wavelength range (656 nm) with a bandwidth of 7 nm and another in the OIII range (501 nm.) Most diffuse nebulae are "brightest" in these two ranges. The two narrow transmission ranges filter out light pollution and distracting moonlight, respectively, making them uniquely effective at reducing background light for urban astrophotographers
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The filter has a narrow design and is only 5 mm thick (without thread). It is made of high quality Schott glass, with multiple layers of anti-reflective coatings vapour-deposited on its surface.
The Optolong l-eXtreme filter offers a real alternative for those who have a color camera but want to get shots similar to narrow-band photos.
