Nebula Filter UHC 1.25-inch Prism System_Roof Its 80mm aperture and 640mm

Its 80mm aperture and 640mm focal length (f/8) balance magnification and wide-field capability

when we look through hyper wide field eyepieces

In addition to providing a solid footing

Regardless of the height you choose

but you also see the main attraction

Nebula Filter UHC 1.25-inch Prism System_Roof Its 80mm aperture and 640mmExplore Scientific Nebula Filter 1. 25" UHC Range from 458nm to 508nm with peak at 488nm. Transmission 96. 7% UHC This is an ultra high contrast narrow band filter, designed for observing the broad range of nebulae with 1. 25 inch standard eyepieces or filter wheels. The bandpass is tighter than the CLS Nebula Filter, thereby blocking even more light from artificial lights and airglow.