The most powerful telescope orbiting Mars took this view of Earth and its Moon, showing continent-size detail on the planet. The image combines two separate exposures taken last November by the High Resolution Imaging Science Experiment (HiRISE) camera on the Mars Reconnaissance Orbiter. The images were taken to calibrate HiRISE using the known value of reflectance for the Earth-facing side of the Moon. The exposures used to make this composite image were processed separately to optimize detail visible on both Earth and the Moon. The Moon is much darker than Earth and would barely be visible if shown at the same brightness scale as Earth.
The combined view retains the correct positions and sizes of the two bodies relative to each other. The distance between Earth and the Moon is about 30 times the diameter of Earth. Earth and the moon appear closer than they actually are in this image because the observation was planned for a time at which the Moon was almost directly behind Earth as seen from Mars so that the Earth-facing side of the Moon would be visible.
The reddish feature near the middle of the face of Earth is Australia. Mars was about (205 million km from Earth when the images were taken.
Image Credit: NASA