GSO (Guen Sheng Optical) are a Taiwanese optical manufacturer. They are well known for their range of Ritchey Chretien telescopes due them being particularly low cost. GSO products are often rebadged and are the basis for many brands such as Omegon, TS, Astro-Tech, Revelation and many more. Hyperbolic mirrors used by RC's have traditionally been costly to produce. GSO have successfully combined mass production with good quality to offer reflective optics that provide significant value. Additionally, GSO have also been able to bring carbon fibre truss construction to mass production. As well as Ritchey Chretien's, GSO offers excellent Newtonian and classic Cassegrain optics. The latter make good use of GSO's expertise by combining a parabolic primary (Newtonian) with a hyperbolic secondary (Ritchey Chretien) to provide a scope that offers many of the advantages of the Ritchey Chretien but that offers better performance for visual use and planetary imaging.