Night sky night sky. Aircraft are also visible at night, distinguishable at a distance from other objects because their lights blink. Night sky The term night sky, usually associated with astronomy from Earth, refers to the nighttime appearance of celestial objects like stars, planets, and the Moon, which are visible in a clear sky between sunset and sunrise, when the Sun is below the horizon. Natural light sources in a night sky include moonlight, starlight, and airglow, depending on location and timing. Aurorae light up the skies above the polar circles. Occasionally, a large coronal mass ejection from the Sun or simply
Southern Hemisphere oceanic. This zone includes the southern tip of Uruguay and South Africa; the southern half of Chile and Argentina; parts of Australia, going south from Adelaide, and all of New Zealand. The Sagittarius constellation that includes the galactic centre is a southern constellation and this, combined with clearer skies, makes for excellent viewing of the night sky from the Southern Hemisphere with brighter and more numerous stars. Forests in the Southern Hemisphere have special features which set them apart from those in the Northern Hemisphere. Both Chile and Australia share, for example, unique beech species or "Nothofagus", and New Zealand