Has a Satellite Been Watching You?

Have you ever wondered how many satellites have passed overhead while you've been going about your daily business? Probably quite a few. But how many of them were actually looking at you? Watched is an intriguing new interactive map which attempts to answer that question by revealing which satellites have passed over any location on Earth during the last seven days, and, more interestingly, which of them actually took a photograph.

Visit Watched and enter any location in the world. The map will then reconstruct the satellite activity above that spot over the previous week, identifying the satellite that passed within viewing range and searching public satellite imagery archives for photographs captured during those passes.

The result is a fascinating combination of satellite tracking, Earth observation imagery and a 3D globe. You can replay the satellite passes, watch their trajectories around the Earth and browse the photographs taken during each encounter. The globe even includes the positions of thousands of other tracked objects orbiting our planet, illuminated by the real position of the Sun.

Not every satellite that passes overhead is necessarily taking a photograph, however. Watched is careful to distinguish between different levels of observation. A satellite is labelled Watched when an actual image of your chosen location can be found in a public archive. Likely Watched means a satellite's camera covered the location, but no photograph has been published. Could Have Pointed Here identifies commercial satellites which were in a position to photograph the location but whose operators do not disclose where their cameras were pointing. Finally, Passed Overhead simply means that a satellite crossed your patch of sky.

There are some important limitations. Watched cannot track classified military and spy satellites, and commercial satellite operators do not generally reveal their imaging schedules. Nor does the application provide live surveillance: satellite photographs can take several hours or even days to appear in public archives. And before you start worrying about being photographed in your back garden, the imagery is not nearly that detailed. At best, a single pixel represents around 10 metres on the ground.