Celestial Objects to Observe

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.

Celestial Objects to Observe

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.

Astronomical Tools

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.