H-Beta Filter 2-One of the most important obstacles for the exploration of the night sky is the brightening of the night sky by artificial lights, such as streetlights. The night sky is not really dark in the vicinity of towns or cities, which reduc. H-Beta Filter 2" This high performance CCD filter transmits only the Hydogen Beta emission line, and therefore is useful for greatly increasing the contrast of objects that glow in the corresponding region of the spectrum, for example the Horsehead, Cocoon and California nebulae.. Orion or Lumicon 2 H-Beta filter - posted in Eyepieces: I have been thinking about getting a H-Beta filter and trying to see the Horsehead now that I have a 14" scope. I have always been happy with my Orion products but I have not done much research on filters until recently. Im looking at 2" now thanks to Don reminding me that they screw into . The Astronomik H-beta is a filter for visual observation, in particular with instruments of larger aperture. It lets the light of the H-beta emission line pass nearly unhindered and blocks the remaining spectral range to the extent that the eye is dark adapted.. The combination of an H-Beta filter and dark skies allow you to see elusive California Nebula. Orion's Hydrogen-Beta eyepiece filter makes it possible to view the elusive Horsehead, California, and Cocoon Nebulas in dark skies. The Explore Scientific H-beta nebula filter blocks all other colours (and thereby nearly all of the artificial light) and only the emission line of the hydrogen can pass the filter..