A variable star is one whose brightness as seen from Earth fluctuates. This variation may be caused by a change in the quantity or wavelength of the emitted light or by something partly blocking the light. Intrinsic variables are stars whose luminosity actually changes. Extrinsic variables are those stars whose apparent changes in brightness are due to changes in the amount of their light that can reach the observer. Discovering a previous unreported variable star would be the highlight of many amateur astronomers time in the hobby