SVBONY SV132 Astronomical Filter Lens 2 Inch 25nm H-Beta for Nebula Observation Astronomical Telescope Accessories

Description The H Beta filter is a narrow band filter specially designed for visual inspection It is mainly aimed at 486nm blue line spectrum nebulae It filters out the interference of other light and can improve the contrast of the nebula The hydrogen beta line with the central wavelength of 486nm of H Beta is suitable for observing the difficult to capture Horsehead Nebula and California Nebula in Orion Features 1 Effectively reduce the reflected light and the image is clear and sharp 2 Using excellent lens grinding technology to improve the light transmittance of the filter 3 Good hand feeling non slip easy to install 4 Suitable for observing detailed conditions of remote nebula Specifications Model SV132Type H BetaSize 2 inchesSubstrate B270Substrate thickness 1 85mmWavelength range 400 700nmCWL 486nm±2nmHalf height width 25nm±2nmT peak 90 Blocking OD3 300 1100nmClear aperture 44mmSurface quality 60 40Surface parallelism 1 4λParallelism 30 Package Included 1 X SV132 Filter1 X Plastic Case