Use our interactive observing tool to say which of the planet's four largest moons is which.
Use this telescope calculator to tell you how changing out eyepieces and accessories will affect your telescope's performance.
The International Space Station passes over virtually all of Earth's populated areas, and you can spot it easily with your eyes alone — if you know where and when to look for it.
The International Space Station often passes close to the Moon, Sun, and naked-eye planets. Use this tool to plan viewing these close encounters.