Telescope Calculator: How Does Your Telescope Perform?
Use this telescope calculator to tell you how changing out eyepieces and accessories will affect your telescope's performance.
Satellite Tracking Tool: Track the ISS & Hubble
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.
Satellite Transit Tool: Spot ISS Transits of the Sun and Moon
The International Space Station often passes close to the Moon, Sun, and naked-eye planets. Use this tool to plan viewing these close encounters.