Astronomy for Beginners
Here’s where you’ll find observing guides, how-to articles and great astronomy hints and tips. Don’t forget to also check out our comprehensive astronomy dictionary.
When a celestial body emerges from a shadow or from a transit.
These are rocky worlds found by extrasolar planet searches in recent years. They’re more massive than the Earth, but generally no larger than about 10 Earth masses.
These are craters who have been infilled, buried or submerged by geological processes but are sometimes still just visible on the surface of a planet or moon.