• more aggressive than the UHC filter, it allows great filtration of artificial lights and shining atmosphere
• when observing under heavily polluted urban or suburban skies, the Orion Ultrablock filter can dramatically improve the quality of emission nebulae and planetary nebulae
• allows observation of features and details that would normally be lost due to light pollution
• blocks all light pollution leaving critical lines of h-? and ionized oxygen
• also improves the image quality of other nebulae, galaxies, open clusters and globular clusters
• filter in a metal frame, fits every 2 "eyepiece with a filter thread

The filter blocks the light of mercury vapor very well while maintaining critically important emission lines typical for the h-? and h-? nebulae - the background seems much darker, the contrast increases significantly. A double ionized oxygen line is also passed - typically emitted by nebulae. The view of galaxies and clusters is also improved, though to a lesser extent.