The Long Range Reconnaissance Imager (LORRI) on New Horizons acquired images of the Pluto field three days apart in late September 2006, in order to see Pluto's motion against a dense background of stars. LORRI took three frames at 1-second exposures on both Sept. 21 and Sept. 24. Because it moved along its predicted path, Pluto was detected in all six images.
These images are displayed using false-color to represent different intensities: the lowest intensity level is black, different shades of red mark intermediate intensities, and the highest intensity is white.
The images appear pixilated because they were obtained in a mode that compensates for the drift in spacecraft pointing over long exposure times. LORRI also made these observations before operators uploaded new flight-control software in October; the upgraded software package includes an optical navigation capability that will make LORRI approximately three times more sensitive still than for these Pluto observations.