Humans have been awed by the night sky for countless millennia. We know so much more about the universe than our ancestors, but the same visceral feelings about the vast, silent majesty of the cosmos sweep through our senses.
A wealth of objects and phenomena delight night-sky viewers. Some objects, like the stars, star patterns and constellations, are permanent fixtures in the cosmic tapestry, acting as guideposts to understanding and finding your way around the heavens. Other objects, like the Moon and planets, move along a highway through the constellations and appear to change over time. A few phenomena, like comets, meteors and the northern lights, are relatively fleeting but spectacular sights. Some sky events can be predicted with great accuracy, while others spring wonderful visual surprises.
There are enough sights in the night sky to keep astronomers enthralled for a lifetime. By probing the universe further using binoculars or telescopes, astronomers eager to explore the cosmos are capable of revealing a staggering panorama beyond Earth. Moreover, new technology in the form of high-resolution electronic cameras, in conjunction with computer-controlled telescopes, enable far more of the universe to be observed than the eye at the eyepiece alone can take in.
THE SKY AROUND YOU
As Earth rotates, the stars rise and set, tracing arcs at various heights above the horizon
1 North celestial pole
The northern point in the sky about which all of the stars seem to rotate around the North Star, also known as Polaris.
2 Right ascension
Right ascension is to the sky what longitude is to the surface of Earth, corresponding to east and west directions. It’s measured in hours, minutes and seconds since as Earth rotates we see different parts of the sky through the night.
3 Celestial equator
A great circle on the celestial sphere that lies in the same plane as Earth’s terrestrial equator and is tilted at roughly 23.5 degrees to the ecliptic.
4 Declination
How high an object will rise in the sky. Like Earth’s latitude, declination measures north and south.
