Pentax believe that the eyepiece is crucial to the overall optical performance of a telescope. This is why their eyepieces are engineered to the exacting standards originally required by the astronomy community. Furthermore Pentax are among the elite few who use rare materials such as Lanthanum glass to optimise light transmission for unsurpassed clarity and brightness. Successfully it seems, since astronomers and ornithologists agree that Pentax are among the best available world-wide.