| These Vixen eyepieces use eight lenses in a proprietary five-group design to achieve a uniformly very wide 65 degree apparent field of view (72 degrees in the 42mm 2” model). They use lanthanum (rare earth glass) lenses to minimize chromatic aberrations and astigmatism and provide a uniformly very long 20mm eye relief for eyeglass use, even in the very short 3.5mm focal length model. The focal lengths are designed to run the full gamut of magnifications, from low power to very high power use with all telescope types. They are corrected for use with telescope focal ratios down to f/4. Contrast is quite good, considering the number of lens elements, and they have excellent center to edge sharpness, with very little ghosting. Each lens element is fully multicoated, with its edges blackened for higher contrast. The eyepieces are threaded for standard color and light pollution filters and have rubber grip rings for secure handling. Each has a soft fold-down rubber eyecup to shield the eye from ambient light. They are an excellent choice for those who must wear glasses when observing, although all observers will enjoy the huge deep space vistas they provide, even at very high powers. Their weight is not inconsiderable, so owners of large Dobsonian scopes who pride themselves at the perfect balance of their scopes should give some thought to balance issues with these eyepieces if they are mixed with lighter weight eyepieces.
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