BRAINCAKEResolving Power
The resolving power of a telescope is its ability to show two close objects (for example two stars) as separate images. Light passing through the circular aperture of the objective is diffracted, so each point source forms a small diffraction pattern, not a perfect point.
The Rayleigh criterion states that two point sources are just resolved when the central maximum of the diffraction pattern of one image falls on the first minimum of the other.
The minimum angular separation that can be resolved is:
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Key terms in this lesson
- diffraction
- The spreading out of a wave as it passes through a gap or travels round an obstacle.
More in Astrophysics
- Refracting Telescopes
- Angular Magnification
- Reflecting Telescopes
- Chromatic and Spherical Aberration
- Radio Telescopes
- Charge-Coupled Devices
- Apparent Magnitude
- Parsecs and Light Years
All 24 lessons in Astrophysics · All AQA A-level Physics topics