Orion 5561 2-Inch SkyGlow Astrophotography Filter Use this specially designed 2" astrophotography filter for deep-sky imaging from areas suffering from light pollution Lets you capture astrophotographs in light polluted skies with CCD or DSLR cameras by blocking up to 99% transmission of specific wavelengths responsible for light pollution while passing through vital light wavelengths for pleasing images Enhances contrast of all types of deep-sky objects: galaxies, nebulas, and star clusters Filter with metal filter cell preserves neutral color balance, eliminating need for corrective color processing later Enables longer astrophotography exposure times without background saturation due to sky glow pollution