Astronomical 3nm SHO filter, i.e. H-Alpha 3nm/Sll 3nm/Olll 3nm, corresponds to 656.3 nm/671.6 nm/500.7 nm in emission band.  

At present, there are only a handful of manufacturers producing 3nm filters in China, and the peak transmittance of this 3nm filter provided by our company is ≥ 88%, which is higher than 85% of ordinary manufacturers; Cut-off range: 300-1100nm;; The cutoff depth is 300-800nm OD6/801-1150nm OD5, which is at the leading level in the industry and can be customized in different sizes according to customers' needs. 

IBS coating halo elimination technology is adopted, Widely used in astronomical halo-free deep space photography, It can make the emission spectral lines of the nebula collect as much energy as possible through cumulative exposure without generating halo, have higher contrast and make the level of the nebula richer and more delicate. It mainly aims at the problem of bright starlight halo that has been plagued for a long time, and bid farewell to the "old problem" of halo through the optimization of substrate and unique coating process.