Diurnal motion

Polaris

Powers of ten (also called 'scientific notation')

Light-year (l.y.)

Look-back time

The difference between Ptolemy's and Copernicus' models of the Solar System

Parallax

Confirmation of General Relativity by the precession of Mercury's orbit

Relative wavelengths of gamma rays, x rays, ultraviolet light, visible light, infrared, radio waves

Particles that make up an atom

The three types of spectra: continuous, emission, absorption

The proton-proton cycle (you need not memorize the detailed reactions)

Spectral classes (types)

Hertzsprung-Russell Diagram

Main sequence

Dwarf star

White dwarf

Brown dwarf

Chandrasekhar limit

Interstellar medium (ISM)

Interstellar reddening

Giant molecular clouds

Synchrotron radiation (synchrotron emission)

Supernova, Types Ia, Ib and Ic, II

Neutron star

Black hole

Extrasolar planets