| For which objects is this filter suitable? The TS O-III filter is especially designed for gas- and planetary nebulae. Famous objects like the Dumbell, Cirrus and North America Nebula can be observed much better. The observation of minour nebulae is often only possible by using an O-III filter. For which telescopes is this filter suitable? We recommend this filter for all kinds of telescopes with an aperture of 90mm and bigger. It is easily screwed into the filter thread of an 1.25" eyepiece. The difference - View without filter / UHC filter / O-III filter... on M27 The pictures show the view through a medium amateur telescope under average conditions. 
M27 without filter The nebula appears very faint | with UHC filter the contrast enhancement is clearly visible, background stars can be seen | with O-III filter extreme contrast enhancement, the background magnitude is strongly reduced | These pictures illustrate the effect of the O-III filter and are also a useful comparison between O-III and UHC filter. From our point of view, the O-III filter is not a replacement but an addendum to the UHC filter. The O-III filter brings extreme contrast enhancement but darkens background objects and "swallows" fainter stars. The overall impression is alienated but faint detail in the desired object itself are better visible. Scope of delivery: -- 1.25" interference O-III filter -- Metal socket with filter thread on both sides -- Robust plastic storage and transport case  |