This image shows the lights of Argentina’s capital city, Buenos Aires. The different colors (pink, white, and gray) define different types and generations of streetlights. The density of the lights reflects the density of urban population and industrial development. Four major highways can be seen diverging from the city center, they are probably more visible due to the well-known late-night urban traffic of weekend Buenos Aires.
ISS Increment 6 Science Officer, Don Pettit, pioneered an approach using a home-made tracking system to track the ground as it moves relative to the Station, allowing him to acquire long-exposure images under low light conditions using very long exposures. Don’s ingenious “Barn-Door Tracker” is a camera mount with a rigged with a hand drill to create a motion tracking system (see http://science.nasa.gov/ppod/y2003/10apr_barndoor.htm).
Why is this image unique?: This image contains a level of detail for city lights at night (in this picture about 30 m/pixel) that cannot be attained by any other satellites. Only a few satellites, such as the Defense Meteorological Satellite Program (DMSP) are able to capture night imagery of cities, and these have a much coarser spatial resolution (500 m – 1 km/pixel).
ISS006-E-24987, 8 February 2003, 58mm lens
The Gateway to Astronaut Photography of Earth, http://eol.jsc.nasa.gov
1. Lulla K. Nightime urban imagery from International Space Station: potential applications for urban analyses and modeling. 69. 2003;69(9):941-2.