NASA's Mars rover Curiosity acquired this picture using its Mars Hand Lens Imager (MAHLI), located on the turret at the end of the rover's robotic arm, on January 23, 2013, Sol 165 of the Mars Science Laboratory Mission, at 01:01:35 UTC. The picture is a single frame acquired using MAHLI's video command capability. Video commanding on MAHLI simply means that a sequence of images was acquired at a regular time interval using a single command. Acquired more slowly than television frame rates, MAHLI video products are not videos in the familiar sense of the word.
When this video frame was obtained, the focus motor count position was 14639. This number is an indicator of the internal position of the MAHLI lens at the time the picture was acquired. This count also tells whether the dust cover was open or closed. Values between 0 and 6000 mean the dust cover was closed; values between 12500 and 16000 occur when the cover is open. For close-up images, the motor count can in some cases be used to estimate the distance between the MAHLI lens and target. For example, in-focus images obtained with the dust cover open for which the lens was 2.5 cm from the target have a motor count near 15270. If the lens is 5 cm from the target, the motor count is near 14360; if 7 cm, 13980; 10 cm, 13635; 15 cm, 13325; 20 cm, 13155; 25 cm, 13050; 30 cm, 12970. These correspond to image scales, in micrometers per pixel, of about 16, 25, 32, 42, 60, 77, 95, and 113.
Image Credit: NASA/JPL-Caltech/MSSS