Frequently Asked Questions About Astronaut-Acquired Photographs

Questions about access to photographs:

How can oblique photos be used?
Is north to the top of the photo?
What areas do the photographs cover?

How can oblique photos be used?

Oblique photos provide information that is not available from other remote sensors. Oblique look angles and lighting can reveal details of topography that are not visible in nadir views. Oblique angles help concentrate the effect of aerosols such as smoke, fog and dust and make them easier to observe in the photographs. If a photo is not too oblique (tilt angle < 5 degrees), a GIS system designed for raster data can be used to register the image to a coordinate system, and remove much of the scale distortion from the original photo. A detailed discussion of technical aspects of look angle and resolution is under construction.

Is north to the top of the photo?

Very rarely. Because the astronaut can look in any direction out the window of the spacecraft, north can be in any direction.

What areas do the photographs cover?

Sample coverage of a 28.5 degree inclination mission >>

Sample coverage of a 57.1 degree inclination mission >>

Astronauts have photographed much of the world's surface. The area that an astronaut on a specific mission can see and photograph depends on the altitude and inclination of the spacecraft. It also depends on the daylight cycle on the ground when the spacecraft passes over an area. Space Shuttle missions usually vary in inclination from 28.5 to 51.6. The inclination gives a rough estimate of the maximum and minimum latitudes visible to the astronauts.

For more information, see the EarthKam library under Satellite Ground Tracks. The EarthKam webpage is at http://www.earthkam.ucsd.edu/.