Masuyama eyepieces are sought after for their clear, high-contrast images and feature a five-element "hybrid Plössl" design. They offer much better edge-of-field performance and improved colour performance compared to Plössls and other competing designs. Masuyama eyepieces achieve high contrast through a much smoother grind than any other premium eyepiece, as well as internal baffles in the long eyepiece barrel.
Despite their large field of view, the short-focus Masuyama eyepieces are highly recommended for planetary and double star observation. At the same time, the eyepieces are of course very nice overview eyepieces for deep sky observation. The long-focus eyepieces are well suited for finding and observing large deep sky objects.
The eyepieces date back to the renowned optician Dr. Masuyama, who developed many of the best Japanese eyepieces of the 1960s and 1970s. Among other things, Dr. Masuyama designed an eyepiece with a focal length of 100 mm, which was used for visual observation on the historic 60-inch telescope at Mount Wilson Observatory in California. After almost 30 years, the legendary Masuyama eyepieces are back in production. They are manufactured by Ohi Optical using state-of-the-art glass and multi-layer technology made in Japan!