Meade Oxygen-III (O-III) nebular filters provide an extraordinary level of nebular filtration on diffuse and planetary nebulae. Observations of these nebulae in a city environment with the O-III filter often yield more image contrast than observations of the same objects in dark sky settings without the filter!
The O-III filter extracts more than 80% of the light emanating from the two oxygen-III spectral lines at 496 and 501nm. Objects such as the Omega (Swan) Nebula (M17) in Sagittarius, the Orion Nebula (M42) in Orion, the Helix Nebula (NGC 7293) in Aquarius, and the Eagle Nebula (M16) in Serpens are revealed in dramatically increased detail. Meade 60-layer interference coating technology isolates the desirable O-III lines while attenuating other spectral lines virtually to zero. As with Meade Narrowband Filters, the O-III Filters are complements to other Meade nebular filters. The effectiveness of each filter type is highly dependent on the physical characteristics of the particular nebula being observed.
The #911X threads onto the rear cells of Meade LX-series mirror-lens telescopes and as well as to the rear cells of other Schmidt-Cassegrain telescopes. In this manner the telescopes are converted into a basic nebular mode, for visual observing or for photography with the T-Adapter or Off-Axis Guider. The advantage of this rear cell filter is that it affords the user the convenience of exchanging eyepieces quickly, whether 2.00" or 1.25". It also works with deep space photography accessories and will seal the rear cell from incoming dust.
