| Originally designed by Austrian optician Georg Simon Plössl in 1860, the Plössl eyepiece languished in relative obscurity for nearly 100 years until it was updated and brought into the modern world in the early 1980s by TeleVue optics. By updating the glass types, coatings, and optical formulations (lens curvatures) used in the classical Plössl, TeleVue started a revolution in the amateur astronomy world by providing premium-quality performance at prices well within reach and reason. The TeleVue Plössls so improved the edge sharpness of the original Plössl design that they were awarded multiple U. S. and international patents. As the superiority of the design became apparent to the astronomical community, “me-too” Plössl eyepieces were soon introduced by other manufacturers to try to cash in on TeleVue’s breakthrough, but the other manufacturers were never able to duplicate the patented TeleVue design. Some of the original TeleVue Plössls – the 55mm, 40mm, and 32mm – are still being made to the exact same specifications as they were when they were introduced back in 1980 to 1982, proof that the original design is still unrivalled. These are the latest versions of those revolutionary eyepieces. They have four lens elements arranged in two sets of paired achromatic lenses, as in the original 1860 design. However, the TeleVues use concave external lenses, rather than the usual convex elements, to provide a significant improvement in the correction of astigmatism and coma at the edge of the field. They are excellent for moderately low to high power use with any type of telescope, including fast reflector "light buckets" having focal ratios as low as f/4. They are superb for planets, nebulas, star clusters – anywhere edge-to-edge sharpness is more important than an extra-wide field or extreme contrast. They have excellent color correction and virtually no field curvature, although minor ghosting may be a problem in eyepiece projection photography with some Schmidt-Cassegrains. All are fully multicoated for the highest possible light transmission and are computer-optimized for excellent correction of chromatic and spherical aberration and astigmatism. They have blackened lens edges for high contrast, and soft fold-down rubber eyecups for observing comfort. Caps are provided for both ends of each eyepiece. Those 20mm and longer in focal length have rubber grip rings for easy handling in cold weather (the shorter focal lengths are physically too short to install a grip ring). All are threaded for filters. The TeleVue 8mm, 11mm, and 25mm Plössls were top-rated in a recent test report of 31 eyepieces in Sky & Telescope magazine. |
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