Planetarium Eyepiece Filter Set 2" High end optical precision at a fraction of the cost is what Planetarium delivers with their 2" Color Filters. Below is some information we pulled from website and we are sure you will agree.....these aren't your typical color filters! Not just another colored filter. Finally, a set of serious tools for the planetary observer. Baader Planetarium's Premium Colored Filters bring a new level of quality and performance to planetary contrast enhancement. Available singly, or as a full set of 6 filters. Extremely High Transmissions result in maximum contrast and isolation of planetary details, even with smaller telescopes. Efficiencies of the three longpass filters (Red, Orange, and Yellow) peaks at 98 percent, and efficiencies of the three bandpass filters (Green, Blue, Dark Blue) achieve 70 percent. Carefully designed spectral characteristics. Filters may be stacked without image degradation or ghosting, in order to provide even narrower passbands. Or, combine with any of the other filters for interesting possibilities. No reduction in sharpness, even at high magnifications or when using the filter far ahead of the focal plane (ie, digital imaging, or in front of a diagonal or binoviewer). With the new 2 inch size, only one filter is needed for binoviewing. Only Baader colored filters have the optical quality necessary for use this far ahead of the focal plane.