UHC (Ultra High Contrast) nebulizer in a 1.25 inch frame with thread on both sides of the luminaire. Perfect for nebula observations, especially when used with a diameter of 15 cm and larger. This filter passes through three nebulizer lines: a double ionized oxygen line (496 and 501 nm) and an H-beta line (486 nm), simultaneously blocking scattered light and light pollution (sodium and mercury lines). As a result, observations of the Orion nebula, nebulae like Laguna, Omega and other extended nebulae are breathtaking. In addition, the filter is an efficient Light Pollution filter.
(measurements on the Varian Cary 100 spectrophotometer, July 2015)
Connection of ALL astronomical filters with the exception of solar film filters (which are filters for the lens) is accomplished by screwing the filter into the frame of the eyepiece from the opposite side than applying the eye (ie from the side that we put in the eyepiece extractor) . The filters can be additionally connected with each other, because they have threads on both sides of the luminaire.