Telescopes

Define resolving power

The smallest angle between two points that we can resolve between.

Define chromatic aberration

Different wavelengths of light have different refractive indices resulting in rays focusing at different points.

Define spherical aberration

Rays passing through different regions of a mirror focus at different points.

What do resolving power and resolution depend on?

Diameter and wavelength of the radiation.

Why do radio telescopes need to be big?

Because radio waves have a large wavelength and large aperture increases collecting power.

Define quantum efficiency

The percentage of photons that liberate an electron.

Define resolution

The smallest change in a quantity being measured that produces a perceptible change in the reading.

What is the quantum efficiency for the human eye?

5%

What is the quantum efficiency for a CCD?

80%

What is collecting power proportional to?

Diameter squared

What is the formula for the minimum angular resolution?

θ = 1.22λ/D

Give an advantage of an optical telescope

Superior resolving power

Give an advantage of a radio telescope

Radio waves have greater penetrating power.