• 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.
The connection of ALL astronomical filters with the exception of solar film filters (which are filters on the lens) is accomplished by screwing the filter into the eyepiece frame from the opposite side than the eye (i.e. from the side we put into the eyepiece). The filters can also be combined with each other because they have threads on both sides of the housing.