For those who enjoy following the visual passes of the International Space Station this App is a great way to follow the location of ISS relative to the position of the viewer, and very accurately anticipate when and where in the sky to look for the best observing experience. Also, a great many other orbiting objects are trackable and viewable, with much information available on every object. A variety of viewing options are available as well. If the circle surrounding the satellite is entirely within the nighttime area, then the satellite will not be visible.