Astronomical Tools

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.

Astronomical Tools

Satellite Tracking Tool: Track the ISS, Hubble & More

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.

Celestial Objects to Observe

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.

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