[Martian sunset over Chryse Planitia on Mars]
Image Not Available
Photograph
[Martian sunset over Chryse Planitia on Mars]
August 20, 1976
Chromogenic development print
Image: 17.8 x 24.1 cm
Overall: 20.3 x 25.4 cm
Museum accession
Inscriptions verso (applied label, typed): NATIONAL AERONATICS AND SPACE ADMINISTRATION/ VIKING NEWS CENTER/ PASADENA, CALIFORNIA/ (213) 354-6000/ PHOTO CAPTION/ Viking 1-75/ P-17704 (color)/ September 8, 1976/
Martian sunset over Chryse Planitia was photographed on August 20 by Viking 1./ The camera began scanning the scene from the left about 4 minutes after the sun/ had dipped below the horizon, continuing for 10 minutes and covering 120 degrees/ from left to right. The sun had set nearly 3 degrees below the horizon by the time/ the picture was completed. The Martian surface appears almost black. The most/ prominent feature in the foreground is a silhouette of the top of one of Viking's/ power system covers (far right). The horizon line is sharp, and, 5 degrees above/ it, the sky color grades from blue to red looking to the left from the region of the/ sky above the sun. Very near the sun position, the sky appears white in the picture/ due to saturation of the camera. The blue to red color variation is explained/ by a combination of scattering and absorption of sunlight by atmospheric particles./ Scatterings by micron-sized particles enhances the blue in the region close to the/ sun's position. At the larger scattering angles, preferential absorption of blue/ light by the particles gives the sky a progressively redder tinge. Darkening/ of the sky in all wavelengths very close to the horizon, which is most evident near/ the sun position, is caused by extinction in the very long optical path through the/ atmosphere between the sun and the camera in that portion of the sky.
Martian sunset over Chryse Planitia was photographed on August 20 by Viking 1./ The camera began scanning the scene from the left about 4 minutes after the sun/ had dipped below the horizon, continuing for 10 minutes and covering 120 degrees/ from left to right. The sun had set nearly 3 degrees below the horizon by the time/ the picture was completed. The Martian surface appears almost black. The most/ prominent feature in the foreground is a silhouette of the top of one of Viking's/ power system covers (far right). The horizon line is sharp, and, 5 degrees above/ it, the sky color grades from blue to red looking to the left from the region of the/ sky above the sun. Very near the sun position, the sky appears white in the picture/ due to saturation of the camera. The blue to red color variation is explained/ by a combination of scattering and absorption of sunlight by atmospheric particles./ Scatterings by micron-sized particles enhances the blue in the region close to the/ sun's position. At the larger scattering angles, preferential absorption of blue/ light by the particles gives the sky a progressively redder tinge. Darkening/ of the sky in all wavelengths very close to the horizon, which is most evident near/ the sun position, is caused by extinction in the very long optical path through the/ atmosphere between the sun and the camera in that portion of the sky.
