Baader PlanetariumYellow 495nm Long-Pass Filter, 2" Eyepiece

I use this filter for EAA with an Orion 120ST achromat. Eliminates CA. Color cast is easily corrected in software, though the final color balance will bot be completely accurate, which to me is not an issue for EAA use. No other CA filter even comes close to this filter in fast achromats. The very expensive "semi-apo" filter has a more natural color but it leaves a lot of CA in images and significantly dims the image visually.

Clear glass from edge to edge. fits perfectly in Televue eyepieces. This is what you use to make Saturn pop out at you, to see the bands in the clouds and the North Polar Hexagon. The bigger the scope you use the better as the filter really cuts down on the light making it to your eyes. I'd not use this on anything smaller than 6" aperture.Do not use this on Orion Eyepieces as they have a different threading.

Works great for killing the purple fringes ("blue bloat") on stars when imaging with my achromat refractor. The yellow tint threw me at first, but Pixinsight easily removes it from images during processing.