The International Space Station (ISS) orbits the Earth at an altitude of approximately 408 kilometers (253 miles), completing about 15.5 orbits per day. Due to its relatively low orbit, the ISS can be visible from many parts of the world, but its visibility depends on various factors such as the observer's location, time of day, and the station's orbital path.
The visibility of the ISS is influenced by the station's trajectory, which follows a specific path around the Earth. The station's orbit is inclined at an angle of approximately 51.6 degrees relative to the equator. This means that as the Earth rotates, the ISS orbits over different regions of the planet on successive passes.
Since the Earth rotates beneath the orbit of the ISS, the station's visibility from a specific location depends on whether the observer happens to be in the path of one of its orbits during a pass overhead. The visibility also depends on factors such as the station's altitude, the observer's latitude, and atmospheric conditions.
In general, the ISS is visible from a wide range of latitudes, spanning from approximately 51.6 degrees north to 51.6 degrees south. However, it may not be visible during every pass, as some orbits may not pass directly over a particular region.
To determine when the ISS will be visible from your specific location, you can use various tools and websites that provide real-time tracking and visibility predictions. These resources take into account your geographic coordinates and provide information about upcoming passes of the ISS visible from your area.
It's worth noting that the ISS is generally visible during nighttime passes when the station is illuminated by sunlight while the observer's location is in darkness. The station appears as a bright, fast-moving point of light, similar to a moving star, and can be quite spectacular to observe when conditions are favorable.