SVBONY Telescope Filter 2" CLS Broadband Filter, Reduce City Light Pollution Suitable for Deep Sky Visual Astronomical Photography

SVBONY Telescope Filter 2" CLS Broadband Filter, Reduce City Light Pollution Suitable for Deep Sky Visual Astronomical Photography

• Evaporation with Ion-assisted deposition coating technology for durability and resistance to scratching;as well as stability on CWL (central wavelength) no deviation affected by temperature change
• Planetary rotation system offers precision and homogeneity of coatings ensuring high value on transmission of pass band and Optical density of off-band
• 90% transmission of main nebula emission lines;such as Ha 656nm;OIII 496nm;500nm;SII672nm and H-beta 486nm
• 0.1% transmission of off-band;specifically the major emission lines of artificial light pollution;such as Na 589nm;Hg 435nmand 578nm
• Suitable for color CCD cameras and unmodified DSLR Urban optical filter can effectively suppress urban harmful light and improve the contrast of shooting target

SVBONY city light suppression broadband filter is designed to improve the visibility of various deep sky objects,<br>By selectively reducing the transmission of wavelengths of light pollutants;specifically those produced <br>by artificial lighting including mercury vapor lamps;both high and low pressure sodium <p> vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere;such as sky glow <p> <b>Using:</b><br> Together with the highly transparent in main nebula emission lines at OIII 496nm and 500nm;H-beta 486nm;NII 654nm and 658nm;H-alpha 656nm<p> as well as SII 672nm;the filter is suitable for enhancing the contrast and getting more details for both visual and photographic purpose at sub-rural area<p> <b>Outstanding Features:</b><p> <b>Coating:</b><br> Multi layers anti-reflection coating.Non cementing optical substrate coating<p> <b>Filter:</b><br> Ultra-thin filter cell minimize vignetting by maximize possible<p> <b>Extinction Treatment:</b><br> Aerometal material precise CNC machining sand blasting Process black anodized finish extinction treatment to prevent reflection laser <p> <b>CLS:</b><br> engraving no fading CLS with wider pass-band than UHC and hence is more favored when observing under mild to moderate light pollution<p> <b>Light pollution filter do not eliminate the effects of light pollution or increase the object's brightness;<br> in many cases;they increase the contrast between nebula and night sky;not brightening the nebula</b><p> <b>Warning:</b><br> the filters of SVBONY are not designed for sun observation;don not look directly into the sun with SVBONY filter;otherwise it will burn the eyes<p> <b>Specifications:</b><br> Type: city light suppression filter (CLS Filter) Material: optical glass lens;aluminum frame Thread: Standard M48.5x0.75mm<p> <b>Package includes:</b><br> 1xSVBONY 2" CLS filter<br> 1xsturdy plastic case