Cities at Night is a citizen science project that aims to create a map, similar to Google maps, of the earth at night using night time colour photographs taken by astronauts onboard the ISS.

When visiting Paris for the weekend, one easily takes over 300 tourist pictures; imagine how many you would take if you were out in space. That is exactly what happens to the astronauts out in space. They easily take hundreds of photographs of earth and although some of those contain carefully selected frames, focus and exposure, many of the pictures are taken automatically so that the astronauts can continue working on their experiments.

NASA has a database with almost half a million pictures taken by the astronauts on the International Space Station.To organise all this data with the use of computers would be infeasible since it would take extremely complex algorithms to interpret the photographs.

The human eye, however, knows immediately if the camera was pointing at a city or simply at the stars. For this reason we created Cities at Night, a platform with different apps with which anyone can help while enjoying beautiful pictures taken from space.