cassegrainian telescope
An astronomer adjusts the focus of a Cassegrainian telescope under a starry sky.
Noun: A Cassegrainian telescope is a specific optical design for a reflecting telescope. It uses a concave parabolic primary mirror to collect and initially focus light. This light is then reflected off a convex hyperbolic secondary mirror, which directs it back through a hole in the center of the primary mirror to the eyepiece or instrument located behind it.
The term is used to describe a particular configuration of a reflecting telescope, named after the French sculptor and mirror-maker Laurent Cassegrain, who is credited with proposing the design. - The observatory's main instrument is a large Cassegrainian telescope. - For planetary observation, many amateur astronomers prefer a Cassegrainian telescope due to its compact tube length.
- Cassegrain focus: The focal point in a Cassegrainian telescope, located behind the primary mirror. This term is often used to describe the location where scientific instruments are mounted on large professional telescopes.
- The spectrograph is installed at the Cassegrain focus of the telescope.
- Cassegrain telescope: A common alternative spelling and the more frequently used term in modern astronomy.
- Ritchey–Chrétien telescope: A specialized, improved variant of the Cassegrain design that uses hyperbolic mirrors for both the primary and secondary to eliminate optical aberrations (coma). It is a subtype of Cassegrainian telescopes.
- Schmidt–Cassegrain telescope (SCT): A popular catadioptric telescope that combines a spherical primary mirror with a corrector plate (a lens) and a Cassegrain-style secondary mirror configuration.
- Cassegrain reflector
- Compound telescope (This is a broader category that includes Cassegrainian designs along with others like the Maksutov–Cassegrain.)
- Cassegrain configuration: Refers to the optical layout itself, not just the complete telescope.
- The new satellite uses a Cassegrain configuration for its imaging system.
An astronomer adjusts the focus of a Cassegrainian telescope under a starry sky.
- a reflecting telescope that has a paraboloidal primary mirror and a hyperboloidal secondary mirror; light is brought to a focus through an aperture in the center of the primary mirror