The Ritchey Chretien Telescope design is used in some of the most famous telescopes like Hubble, SLOAN Digital Sky Survey, and LORRI on board the New Horizons spacecraft. RC Telescopes, as they are commonly referred to, only use hyperbolic mirrors to eliminate optical errors like coma and chromatic aberrations off-axis while producing the flattest focal plane possible without lenses. Since they only use two reflective surfaces, Ritchey Chretiens are also very efficient with light compared to most other telescope systems that use 4, 6, or event more surfaces that will reduce the amount of light hitting the focal plane. Take a look down below to see some pros and cons of buying a Ritchey Chretien Telescope.
The lack of refractive lens elements allows this telescope design to detect wavelengths broader the visual spectrum making them very useful for measurements in the ultraviolet (UV), near-infrared (NIR), and infrared (IR) wavelengths. RC telescopes are also very modular, field flatteners are available for expanding the corrected image circle, reducers can be integrated for faster focal ratios, and barlows can be used for longer focal lengths. With all these properties within one telescope, it's easy to see why RCs are extremely desirable among researchers and advanced astrophotographers.
Advantages & Disadvantages of Ritchey Chretien Telescopes
Advantages: They deliver high quality images with very little distortion and are ideal for serious astrophotography. They have a flat field of view which means that objects will be very sharp right out to the edges of the image. RC's have generally shorter exposure times than similar telescopes like SCT's because of their faster focal ratios. At smaller sizes, they can be compact, light, and easy to transport. Because of these reasons, RC Telescopes are often used for research and advanced imagers.
Disadvantages: The hyperbolic mirrors in a Ritchey Chretien Telescope are very difficult to manufacture. For this reason, the cost on RC's tend to be much higher than other telescopes of similar apertures. They are usually best for imaging. If you plan to use one for viewing you will generally need to use a diagonal with your eyepiece because of the angle of the telescope when looking at the night sky.