NASA’s Mars rover Curiosity has taken the first photographs of a camera calibration target that actually includes a classic United States coin. Found in the target is a 1909 V.D.B. Lincoln cent. The century old coin and other calibration devices are used by Curiosity’s Mars Hand Lens Imager ( MAHLI) to test its performance. MAHLI is capable of focusing on objects as close as 2.1 centimeters up to infinity.
The choice to include the Lincoln cent was the recommendation of MAHLI’s principal investigator, Ken Edgett.
“The penny is on the MAHLI calibration target as a tip of the hat to geologists’ informal practice of placing a coin or other object of known scale in their photographs. A more formal practice is to use an object with scale marked in millimeters, centimeters or meters,” Edgett said. “Of course, this penny can’t be moved around and placed in MAHLI images; it stays affixed to the rover.”