Abstract: An image data capturing arrangement (1) has at least two image data capturing devices. At least one first image data capturing device (2) is adapted to capture data of one or more first images of an object along a first image capturing axis 4, and at least one second image data capturing device (6) is adapted to capture data of one or more second images of stars along a second image capturing axis 8. The second image capturing axis (8) has a known orientation relative to the first image capturing axis (4), and a reference clock for assigning a time stamp to each first and second image data.