The first piece of the International Space Station, a cargo block named Zarya, went into orbit in 1998. Ever since, the ISS has been steadily picking up pieces, becoming bigger and more reflective. It is now the second brightest object in the night sky, bested only by the Moon. As the orbital platform has grown, it has become easier and easier to see from the ground. If, that is, you know where to look.
Websites have been around for a while that will let you calculate when and where to look up to the heavens, but NASA recently launched a new service that should take pretty much all of the effort out of it. The agency’s new Spot the Station program will email or text you when the station is in your area. And, says NASA, they’ll try not to waste your time.
This service will only notify you of “good” sighting opportunities- that is, sightings that are high enough in the sky (40 degrees or more) and last long enough to give you the best view of the orbiting laboratory. This will be anywhere from once or twice a week to once or twice a month, depending on the space station’s orbit.
But once you have your bearings and your alert, what are you looking for? Universe Today:
The International Space Station always passes over starting from a westerly part of the sky, but not always from the same point.
… The ISS looks like an incredibly bright, fast-moving star and can be mistaken for an aircraft. However, the ISS has no flashing lights and it can be much brighter. It seemingly just glides across the sky.
According to Universe Today, though the ISS passes around the Earth quite quickly, you can expect a good pass for watching every six weeks.
More from Smithsonian.com:
Find the International Space Station with Twitter