5% off through July 12th. Discount will be reflected in your shopping cart at checkout. New purchases only, not valid on previous sales.
Yes, our inventory is accurate!
Qualifies Towards Free Ground Economy Shipping (CONUS Only) For Most Orders Of $149 Or More
This is a 2" Hutech IDAS Night Glow Suppression Pollution filter in very good condition. The optics have a small amount of dust on the back side that we have not been able to remove; see the photos. We have reduced the price accordingly to account for this condition issue. This includes the jewel case.
Description:
The NGS1 is the world-first filter that suppresses both man-made and night glow interferences to the green, orange and red ranges. This is the same filter that was previously sold as the IDAS LPS-D3.
Night Glow: OI (557.7nm, 630.0nm, 636.4nm), NaI (589.0nm, 589.6nm)
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 Shigemi Numasawa):
Image ideally processed to reproduce the NGS1:effect
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.
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.
- Highly durable thin layers of which hardness equals to quartz glasses. Tremendously improved adherence between the
substrate and the multi-layers set. - 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.
*This product is an interference filter. Its spectrum characteristics will be subject to the incidence of incoming light. Please carefully read the following instruction for proper use:
When the NGS1 is placed before the lens:
Use a lens having the light incidence angle of 14 degrees or lower (field angle of 34 degrees or lower).
Specifications:
- M48 x 0.75
- Filter thickness: 2.0mm (Previous version NGS1-48mmS was 2.5mm thick)
- Lightweight frame
Other Information
- Country of Manufacture: Japan