About this product
Part Number: 1.25 SII 7nm
The Askar S II 7nm filter is suitable for the imaging of S II emitting nebulae or some supernova remnants.
It has high 90% peak transmission at a centre wavelength of 671.6nm. The 7nm narrow bandwidth enables this astro imaging filter to block light pollution and other unwanted artificial lights or night glow hence the Askar S II filter is an ideal filter for astro-imaging in heavily light-polluted locations and delivers enhanced contrast at darker places.
Although there is very little sulfur in nebulae, the emission from the trace of S II in nebulae is rather strong. The deep-red light emitted from S II can bring out quite delicate detail which is different from those regions that release H-alpha light. So this filter works well on those nebulae emitting S II.
Featuring 7nm narrow bandwidth and a peak 90% transmission at a centre wavelength of 671.6nm.
The out-of-band blocking ability is rated at OD4 (0.01%) with a blocking range of 200-1050nm. This filter delivers excellent signal-to-noise ratio and a sharp cut-off rate to attenuate the disturbance from other wavelengths.
The production process is strictly controlled and every single Askar S II narrowband filter is individually examined and tested.
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