The Martian analemma as seen by Opportunity, Mars Years 28 and 29
This Martian analemma shows the seasonal apparent motion of the Sun as seen by the Opportunity rover, as well as the nearly rover-killing faintness of the Sun during the 2007 global dust storm. The tear-drop shape is due to the axial tilt and elliptical orbit of Mars—Mars is farther from the Sun, and moving slowly, when the Sun is seen at the pointy top, and closer to the Sun and speedy when the Sun is seen at the rounded bottom.
The image is a mosaic shown in stereographic projection with the zenith at the center and north at the top. It includes (1) 219 Pancam R8 (solar filter) images shown at 11:02 AM local mean time every 3rd sol for sols 880-1549 (16 July 2006 – 2 June 2008); (2) a multispectral column of sky images (6 frames of Pancam L2-3-4-5-6-7 filters which span the visible spectrum and are rendered in approximately true color) taken on sol 728 (10 February 2006), which is blacked out around the analemma; (3) the “Lyell” panorama taken inside Victoria crater on sols 1332-1379 (23 October 2007 – 11 December 2007) using Pancam’s L-2-5-7 filters (at 753, 535, and 432 nm) and rendered in approximately true color. For about half of the images, the measurement was not made close enough to the normal 11:02 time, and the image was projected to the Sun’s calculated 11:02 position. One sol (left side below center) is missing a nearby Sun image due to normal operations. Several sols (bottom, right of center) show the 2007 dust storm effects, with some missing due to the halting of rover operations.