Baader Premium Eyepiece Filter: Yellow, 495nm Longpass - 2" # FCFY-2 2458311 Freedom from ghost images, even when stacked Striae-free substrates are polished parallel to within 30 seconds of arc to avoid wedge errors Finest 7-layer hard multi-coatings on both faces feature 0.25% residual reflections Extremely high transmission results in maximum contrast and isolation of planetary details, even with smaller telescopes Efficiency of the long-pass filter (Yellow) peaks at 98%