Images of the Earth and moon from Mars were acquired for calibration of HiRISE data, because the spectral reflectance of the moon's near side is well known. When the component images were taken, Mars was about 127 million miles (205 million kilometers) from Earth. (Credit: NASA/JPL-Caltech/University of Arizona)
A composite image of Earth and its moon, as seen from Mars, combines the best Earth image with the best moon image from four sets of images acquired on Nov. 20, 2016, by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter.
Each image was separately processed prior to combining them, which allowed the moon to be bright enough to see. The moon is much darker than Earth and would barely be visible at the same brightness scale. The combined view retains the correct sizes and positions of the two bodies relative to each other.
HiRISE takes images in three wavelength bands: infrared, red and blue-green, similar to Landsat images in which vegetation appears red. The reddish feature in the middle of the Earth image is Australia. Southeast Asia appears as the reddish area (due to vegetation) near the top; Antarctica is the bright blob at bottom-left. Other bright areas are clouds.
The University of Arizona operates HiRISE, which was built by Ball Aerospace & Technologies Corp. NASA's Jet Propulsion Laboratory manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate.
