Sky-Watcher high-performance ED-APO refractors offer premium optical performance for the discriminating amateur astronomer. Refractors are coveted for their superb contrast, high-definition and coal-black sky background that make stars appear like diamonds imbedded in black velvet. SW APO refractors utilize the most modern optical glasses and fabricating techniques to deliver the ultimate in high-fidelity astronomical imaging. Subtle details pop as never seen before in telescopes of lesser optical capability.