Planet
Also called: planets.
A world orbiting the Sun — Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune in our sky.
The planets shine by reflected sunlight and move against the stars from night to night (the word means “wanderer”). They stay close to the ecliptic. Unlike stars, which twinkle, bright planets shine steadily, and a telescope shows each as a small disk.
Jupiter's cloud belts and moons, Saturn's rings, Venus's phases and Mars's polar cap are within reach of any telescope; Uranus and Neptune show tiny blue-green disks.
At the eyepiece
Planets need steady air more than dark skies. Observe them when they're high, and give your telescope time to cool down.
In AstroPilot
Tonight and the sky chart show where each planet is; its page shows the size of its disk and its moons tonight.