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The Astronomik Professional UHC filter is useful for visual observation. The Astronomik professional UHC filter lets the entire radiation from both O-III lines and the H-beta line occur to almost 100%. A second window for the H- alpha line ensures for the fact that also this radiation will also reach the eye. Light Pollution will be reliably filtered out. The Astronomik professional UHC filter has enough light transmission to be enable the astronomer to observe Deep Sky of objects with telescopes as small as 3 inches.
Additionally, the filters are optimized for the use with aperture ratios from F/4 to F/15. Transmission losses, which occur with filters with parallel paths of light rays, occur with the Astronomik filters only with extreme aperture ratios of F/3 or less.
The quality and power of this filter as a tool for observing has impressed many observers. The glass substrate for the filters, used by Astronomik, is the best that is available and results in the best UHC filter on the market. If you use an Astronomik UHC filter, the stars remain tiny points and the difrraction paterns of the stars will not change.