The brightness of stars in the night sky are measured in levels of “magnitude” by astronomers. Stars and constellations of lower magnitudes, as well as sky objects such as nebulae and galaxies that are relatively dim to the naked eye, are more susceptible to light pollution, especially sky glow (brightening of the night sky). This certain type of light pollution reduces the contrast between these objects and the night sky itself, rendering the objects less visible in brighter areas.