Low Sun From Low Ridge

         The Spirit rover acquired this black and white mosaic of the Columbia Hills on Sol 813 (April 16, 2006). The image was acquired late in the Sol, at 16:40 LTST, and shows about 100 degrees in the field of view.

         Spirit's right panoramic camera (Pancam) acquired this blue filter (436 nm) view while the Sun was low in the sky late in the afternoon, from the vantage of her "winter haven" on Low Ridge, where she is parked in a sunward-facing spot to wait out the cold martian winter. Because of the low-angle lighting (sunlight is coming from the left), images like these give superb views of subtle textures in the near field as well as details of the topography in the distance. Husband Hill, where the rover was perched late last summer, rises prominently just left of center in this view. The 150 meter wide field of curving sand ripples named El Dorado lies at the base of Husband Hill. By collecting photos like this at different times-of-day, when lighting comes from different directions, scientists can distinguish surface properties such as color and reflectivity from topography and roughness. By separating these components they can map more details of the geologic terrains in the distance, providing new clues on the geologic history of Gusev crater. This is the first mosaic in what might be a series of such "Topography from Atmospheric Radiance" sequences while Spirit winters over.

Jim Bell
Pancam Instrument Lead
April 27, 2006