Cassegrain telescope
E481877
A Cassegrain telescope is a reflecting telescope design that uses a combination of a primary concave mirror and a secondary convex mirror to fold the optical path and produce a compact instrument with a long effective focal length.
Statements (49)
| Predicate | Object |
|---|---|
| instanceOf |
optical telescope configuration
ⓘ
reflecting telescope design ⓘ |
| canProvide | Cassegrain focus for instruments at back of telescope ⓘ |
| differsFrom | Newtonian telescope by rear focus through primary mirror ⓘ |
| focusesLight | through hole in primary mirror ⓘ |
| hasAberrationConsideration |
coma and field curvature depend on specific variant
ⓘ
spherical aberration control by mirror shapes ⓘ |
| hasAdvantage |
compact tube for given focal length
ⓘ
convenient eyepiece position at back of telescope ⓘ long focal length suitable for high magnification ⓘ |
| hasComponent |
primary mirror with central perforation
ⓘ
secondary mirror mounted on spider or corrector ⓘ |
| hasDesignConstraint |
primary mirror focal ratio affects tube length
ⓘ
secondary mirror curvature determines amplification ⓘ |
| hasDesignGoal |
provide long focal ratio
ⓘ
reduce telescope tube length ⓘ |
| hasDisadvantage |
central obstruction by secondary mirror
ⓘ
more complex alignment than simple reflectors ⓘ |
| hasFocalPlaneLocation | behind primary mirror ⓘ |
| hasHistoricalAttribution | attributed to Laurent Cassegrain ⓘ |
| hasImageOrientation | inverted image at focal plane ⓘ |
| hasMountingInterface | back-end focus for cameras and instruments ⓘ |
| hasOpticalAxis | coaxial primary and secondary mirrors ⓘ |
| hasOpticalPath | folded optical path ⓘ |
| hasProperty |
compact physical length
ⓘ
long effective focal length ⓘ |
| hasRayPath | light reflects from primary to secondary then back through primary ⓘ |
| hasSecondaryMagnification | secondary mirror increases effective focal length ⓘ |
| hasTypicalFocalRatio | f/10 or longer ⓘ |
| hasVariant |
Dall–Kirkham telescope
NERFINISHED
ⓘ
Maksutov–Cassegrain telescope NERFINISHED ⓘ Ritchey–Chrétien telescope NERFINISHED ⓘ Schmidt–Cassegrain telescope NERFINISHED ⓘ classical Cassegrain telescope ⓘ |
| isCommonIn | research telescopes with multiple foci ⓘ |
| isComparedTo | Newtonian telescope ⓘ |
| isUsedFor |
amateur astronomy
ⓘ
astronomical observation ⓘ astrophotography ⓘ high-resolution planetary observation ⓘ narrow-field deep-sky imaging ⓘ professional observatory telescopes ⓘ |
| isUsedIn |
compact consumer telescopes
ⓘ
large professional observatory instruments ⓘ |
| isVariantOf | two-mirror reflecting telescope ⓘ |
| requires | precise collimation of mirrors ⓘ |
| uses |
primary concave mirror
ⓘ
secondary convex mirror ⓘ |
| wasProposedIn | 17th century ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.