Depending on your location on the Earth’s surface, a spacecraft’s position in orbit and the time of day, you may be able to see the International Space Station (ISS) or visiting vehicles as they orbit about 240 statute miles above the planet.
The space station looks like an airplane or a very bright star moving across the sky, except it doesn’t have flashing lights or change direction. It will also be moving considerably faster than a typical airplane (airplanes generally fly at about 600 miles (965 km) per hour; the space station flies at 17,500 miles (28,000 km) per hour).
NASA operates the “Spot The Station” service to provide sighting opportunities in a text listing by city. You also can sign up to receive notices of opportunities in your email inbox or cell phone.
So how do you do it?
Obtain the position of the space station :
What does all this sighting information mean?
“Time: Wed Apr 25 7:45 PM, Visible: 4 min, Max Height: 66 degrees, Appears: WSW, Disappears NE.”
Time is when the sighting opportunity will begin in your local time zone. All sightings will occur within a few hours before or after sunrise or sunset. This is the optimum viewing period as the sun reflects off the space station and contrasts against the darker sky.
Visible is the maximum time period the space station is visible before crossing back below the horizon.
Max Height is measured in degrees (also known as elevation). It represents the height of the space station from the horizon in the night sky. The horizon is at zero degrees, and directly overhead is ninety degrees. If you hold your fist at arm’s length and place your fist resting on the horizon, the top will be about 10 degrees.
Appears is the location in the sky where the station will be visible first. This value, like maximum height, also is measured in degrees from the horizon. The letters represent compass directions — N is north, WNW is west by northwest, and so on.