Feature 1
The NGS1 is the world-first filter that suppresses both man-made and night glow interferences to the green, orange and red ranges.
Night Glow: OI (557.7nm、630.0nm、636.4nm), NaI (589.0nm、589.6nm)

Feature 2
The NGS1 the successor of the conventional IDAS light pollution cut filters, and thus can suppress the inteference from white LED lights. This filter is also effective against low- and high-pressure sodium lamp pollutions.

Night glow interferenced image (photo taken by Mr. Shigemi Numasawa):


Image ideally processed to reproduce the NGS1:effect


Feature 3
The NGS1 is designed based on the same concept as of the other IDAS light pollution cut filters so that it maxmizes the transfer of the light emissions from various emission nebulae, C2 comae of comet heads and CO+ ionized tails of comet tails as well as coninuous spectrum emissions from space. Its transmittance range is intentionally shifted to the longer wave length side. allowing margins for "the shift tendency towards the shorter wave length side against oblique incidences" typically associated with thin-film interference filters. The NGS1 can almost fully transfer the abovementioned nebular emission lines under the conditions , for example, where the incidence of the parallel flux is kept below 14 degrees, or a lens of the F value 2 or faster (or 1.4 or faster depending on lens) is used before this filter.
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Feature 4
The NGS1 filter utilizes the IGAD (ion-Gun AssistDeposition) coating technology which has been applied to our coventional light pollution cut filters. The IGAD technology densifies the multi-layers - the heart of interference filters - resulting in the physical properties that cannot be obtained from the conventional multi-layers.
1) Highly durable thin layers of which hardness equals to quartz glasses. Tremendously improved adherence between the substrate and the multi-layers set.
2) Absolutely almost no aging variation in optical spectral characteristics due to temperature and humidity change as far as used in the regular human living environments.