Release of NAKOH "60GT Optical Tube", a 60mm Aperture Triplet Apochromatic Astronomical Telescope Featuring SD and ED Glass

Sightron Japan Co., Ltd. (Head office: Shinjuku-ku, Tokyo; Representative Director: Akira Watanabe) will release the compact astronomical telescope "60GT Optical Tube" from Nakoh Co., Ltd.'s astronomical telescope brand NAKOH, equipped with a triplet apochromatic optical system combining ED glass and Japanese-made SD glass, along with its dedicated optional accessories, the "60GT 1.0x Flattener" and "60GT 0.65x Reducer", on March 27, 2026.

Product Features Triplet Apochromatic Optical System Featuring SD Glass + ED Glass ・The "NAKOH 60GT" is a triplet apochromatic (APO) telescope with a 60mm effective aperture and 360mm focal length (F6 focal ratio).

・One of the three lenses lavishly uses Japanese-made SD glass, and another uses ED glass. By maximizing the anomalous dispersion characteristics of SD and ED glass, the difference in refractive index for light of different wavelengths is significantly reduced, effectively suppressing chromatic aberration and achieving extremely sharp, high-contrast star images.

・By using the dedicated correction lenses released simultaneously, it can be used as a compact, full-frame compatible flat-field astrograph.

・When using the flattener, the spot radius is approximately 2.1μm at the center and approximately 2.5μm at the outermost edge of a full-frame sensor, providing a uniform and flat imaging field from the center to the periphery.

・When using the reducer, the brightness becomes F3.9, making it suitable for photographing large or faint objects. The spot radius is approximately 2.7μm at the center and approximately 4.6μm at the outermost edge of a full-frame sensor.