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ZWO OIII 7nm Filter - 31mm - OIII31

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ZWO OIII 7nm CCD Imaging Filter - 31mm

OIII, or doubly ionized oxygen, emits light in the blue/green, or teal portion of the spectrum near 500 nm. Planetary nebulae and supernova remnants emit most of their light in the OIII line. OIII is considered the second most popular narrowband imaging filter (behind H-a), and when used in conjunction with H-a and SII, your images will get that tri-color "Hubble Look".

The ZWO OIII 7nm 31mm Filter is unmounted. ZWO narrowband filters are fine-optically polished to reach an accuracy of 1/4 wave. Their performance is further enhanced by multiple layers of anti-reflection coatings.