Background information: Light from the sun takes 8 minutes to reach the earth. The magnitude system for stars and other astronomical objects in our sky is designed so that a difference of 5 magnitudes represents a factor of 100 in brightness, with the larger numbered magnitudes being the dimmest. The dimmest stars seen with the unaided eye in a dark sky are about magnitude 6; the brightest stars (other than the sun) about 0. The planet Venus at times is magnitude -4, the full moon -14 and the sun -27.