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
Northern Cross (asterism) The variable star P Cygni was then considered to be the body of Christ. It is believed that KIC 9832227, a contact binary star system located off the right hand 'arm' of the Northern Cross, merged approximately 1800 years ago producing a luminous red nova which is expected to be visible to the naked eye around 2022. Northern Cross (asterism) The Northern Cross is a prominent astronomical asterism in the northern hemisphere celestial sphere, corresponding closely with the constellation Cygnus The Swan. It is much larger than the more famous Southern Cross and consists of the brightest stars in Cygnus,