Used Optolong 2" S-II 6.5nm Deep Sky Filter

This Optolong 2-inch S-II 6.5nm filter is in excellent condition, transmitting light centered at 672nm and reducing light pollution. It blocks infrared wavelengths and can enhance contrast when used with H-Alpha and OIII filters.

• The Optolong SII filter transmits a 6.5nm bandwidth of light centered at 672nm and drastically reduces other transmissions, including wavelengths responsible for light pollution.
• The filter blocks infrared wavelengths from 700nm to 1100nm.
• The description claims the filter can enhance contrast and reduce the number of visible stars by half when compared to a 12nm SII.