Ritchey-Chrétien reflector

astronomy

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July 13, 2026

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The Ritchey-Chrétien design is a modified Cassegrain reflector telescope. It addresses a limitation of standard parabolic mirrors, which have a narrow field of view. In the Ritchey-Chrétien design, the central part of the primary mirror is deepened from a paraboloid shape, and the secondary mirror is adjusted to compensate. This modification results in a curved focal plane, allowing for higher-quality images across a wider area of the sky, approximately 1°. This design is particularly useful for astronomical applications that require photographing larger sections of the sky.12

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telescope
Reflecting telescopes
The result is the Ritchey-Chrétien design, which has a curved rather than a flat focus. Obviously, the photographic medium must be curved to collect high-quality images across the curved focal plane. The 1-metre telescope of the U.S. Naval Observatory in Flagstaff, Arizona, was one of the early examples of…
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The result is the Ritchey-Chrétien design, which has a curved rather than a flat focus. Obviously, the photographic medium must be curved to collect high-quality images across the curved focal plane. The 1-metre telescope of the U.S. Naval Observatory in Flagstaff, Arizona, was one of the early examples of…
Read More