A classic 2-dimensional UHC nebulosic filter that passes through 2 spectra of the visible spectrum. The first of the bands lies in the vicinity of the spectral lines O-III and H-beta. The second red band contains the spectral line H-alpha. In both of these bands there are the most important lines emitted by the emission nebulae, at the same time the remaining part of the spectrum is completely blocked, including the yellow sodium line coming from the lighthouse as well as other lines coming from various types of ? city ••lights. As a result, the image observed by the filter gains a strong contrast. The background of the sky, illuminated mainly due to street lighting, is clearly darkened, while the light of the nebulae remains unchanged so that much more detail of the observed objects can be retrieved from the background. This filter only works with nebulae emitting radiation in specific spectral lines - emission nebulae and planetary nebulae. In the case of other objects (galaxies, clusters, stars), the use of the UHC-S filter does not improve the visibility but also does not block their visibility as in the case of the ? skbape filters. The transmission in both transmission bands reaches 97% while the spectrum between the bands is completely blocked. The UHC-S filter works best with apertures from 10 cm to 25 cm
The UHC-S filter is made with the highest quality standards. Covered with multilayer anti-reflective coatings, resistant to abrasion during cleaning. It is one of the most popular filters of this type on the astronomical market. Filter designed for attaching glasses and accessories in the 2 "standard.
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.