Svbony Telescope Filter 2inches UHC Filter Aluminum Frame Deep sky Filter for Telescope Eyepiece

• The Svbony 2inch UHC telescope filter is designed to improve the image contrast of observed objects;it can be used not only for celestial observations but for astrophotography
• 95% transmission of main nebula emission lines and 0.1% transmission of off-band specifically the major emission lines of artificial light pollution;great for city and suburban observation
• Double sided multi layer coating and the backside increases the broadband penetration film reduces the reflected light and increases the contrast and image sharpness
• Optical glass lens; Aluminum frame;Precision polished substrate good parallelism and surface precision ensures you used long time
• Including a sturdy plastic box convenient to carry and storage

Light pollution filters are designed to improve the visibility of deep sky objects by blocking out <br>the emission lines from man-made or natural sources which contribute to light pollution.<br>By selectively screening out of some of the background sky glow, the contrast is increased and <br>allows deep sky objects to stand out against the background. It can be used not only for <br>astronomical observations but for astronomical photography.<br><br><b>Spectral Curve</b><br><b>The Major Emission Lines of Nebulae:</b>H-β486.1nm OIII 495.9nm OIII 500.7nm H-α656.3nm<br><b>The Major Emission Lines of Artificial Light Pollution:</b>Hg 435.8nm 546.1nm 577nm 578.1nm;<br>Na 598nm 589.6nm 615.4nm 616.1nm<br><b>Increases the contrast and image sharpness:</b><br>--Double sided multi layer coating and the backside increases the broadband penetration film reduces the reflected light.<br>--95% transmission of main nebula emission lines and 0.1% transmission of off-band specifically <br>the major emission lines of artificial light pollution;great for city and suburban observation.<br><b>Durable and difficult to deform:</b><br>--Optical glass lens, Aluminum frame, Precision polished substrate good parallelism and surface<br>precision ensures you used long time.<br>--Tighter film, high hardness, low temperature drift,more stable.<br><b>NOTE :Do not look at the sun with Svbony filter. </b><br><br><b>Specification:</b><br>Brand: Svbony<br>Type: UHC Filter<br>Material: Optical glass lens, Aluminum Frame<br>Barrel diameter:2''<br>Thread: M48x0.75mm<br>Net Weight: 12.9g / 45oz<br><br><b>Package Includes:</b><br>1 x Svbony 2 inch UHC Filter<br>1 x Sturdy Plastic Case