Astrophysics 03 - Resolution and Power of a Telescope

Define resolution.

The ability to distinguish between two objects with low angular separation.

Explain why telescopes have a limited resolution.

When two objects are far away and their light passes through an aperture, a circular single-slit diffraction pattern occurs for each.

When the light falls on a sensor (eye or a CCD), it can overlap.

If the angular separation is too small, the central maxima superpose, appearing as a single object.

Define the Rayleigh Criteria.

The limit at which two objects can be resolved.

The point at which the central maxima of one diffraction pattern lines up with the first minima of the second.

Give the formula for angular separation of two objects a great distance from the observer.

Angular separation ≈ distance between objects / distance from objects to the observer

θ ≈ x / y

How do you calculate the maximum resolving power of a telescope?

Angular resolution = wavelength of incident light / diameter of the aperture

θ = λ / d