Dobsonian Cassegrain telescopes are a hybrid form of telescope that combines the Dobsonian mount type with the optical design of a Cassegrain telescope. The Dobsonian aspect refers to the mounting system, which is an altazimuth mount known for its simplicity, ease of use, and affordability, providing a stable platform for observing. This mount typically allows for manual adjustments and is favored by amateur astronomers for its simplicity and ability to handle larger apertures at a lower cost compared to other mounts.
On the optical side, the term “Cassegrain” indicates a design that uses both mirrors and lenses to fold the light path, allowing for a compact telescope with a longer focal length. This design typically involves a primary concave mirror and a secondary convex mirror, which redirects the light back through a hole in the primary mirror, resulting in a longer effective focal length. The Cassegrain design is well suited for observing objects that require higher magnification, such as planets and small deep-sky objects.
Combining these two elements allows Dobsonian Cassegrain telescopes to capitalize on the strengths of both systems, providing a powerful observational tool that is both portable and versatile. These telescopes can often offer a good balance of affordability, large aperture, and ease of setup and operation, making them particularly appealing to amateur astronomers who want the benefits of a Cassegrain optical system without the cost and complexity of traditional equatorial mounts.