Sky-Watcher Esprit-150ED 150mm (6"") f1050 Super APO Triplet Optical Tube Assembly. We are proud to introduce the new Sky-Watcher Professional Esprit 3-Element ED apochromatic refractor. These are instruments of the highest quality with optical performance rivalling or exceeding similar telescopes of even the most famous high-end telescope brands.The Esprit Super Apo Triplets are designed for the most demanding astro-imagers but are also fine telescopes for visual observations. The premium, superbly-corrected optical systems deliver high-contrast images full of detail with pin-point stars right up to the edge of the field and zero detectable colour fringing, even on the brightest of objects.