SVBONY SV132 Telescope Filter, 2 inches H-Beta Narrowband Filter, 25nm Visual Nebulosity Eyepiece Filter, for Horsehead Nebula California and Cocoon Nebulae in Dark Skies

Compatibility This filter is with metal mount 2" filter threads and could be connected with 2" eyepieces and 2" threaded diagonal barrels Observation object It’s mainly for Horsehead Nebula California and Cocoon Nebulae in dark skies Improve the contrast of the nebula It is mainly aimed at the 486nm (blue) line spectrum nebula. It filters out the interference of other light and improve the contract of the nebula,you can get clear image of the nebula Specification: Brand: SVBONY Model: SV132 Type: H-Beta Size: 2-Inch Substrate: B270 Substrate Thickness: 1.85mm Wavelength Range: 400-700nm CWL: 486nm±2nm FWHM: 25nm±2nm T peak: 90% Blocking: OD3 @300-1100nm Clear Aperture: 44mm Surface Quality: 60/40 Surface parallelism: 1/4λ Parallelism: 30" Net Weight: 13.2g / 0.47oz Package Includes: 1X SVBONY 2" H-Beta 25nm Filter 1X Sturdy Plastic Cases