Optolong L-Ultimate 3 nm filter (2")

The Optolong L-Ultimate Dual 3 nm Narrowband Filter is specifically 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 (656.3 nm) with a bandwidth of 3 nm and another in the OIII range (500.7 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-Ultimate Dual 3 nm filter offers a real alternative for those who have a colour camera but want to capture images similar to narrow-band photography.