Mars Photos from Mariner 6 and Mariner 7
Mariner 6 flew by Mars on July 31, 1969 and the Mariner 7 flyby followed one week later; shortly after Apollo 11 landed on the Moon (July 21, 1969). The Mariner missions took a series of pictures with a vidicon camera as they approached and passed. Researchers at Northwestern University have corrected the Mariner photos for lens distortion and placed them on the web page of Mark Robinson at Northwestern.
A vidicon camera has a small size and weight compared to the image orthicon cameras used in commercial television at the time (of course today’s CCD cameras have blown them both away). Unfortunately, vidicon tubes have a limited dynamic range and scanning defects that affected the quality of the images.
The same filtering software that improved the Lunar Orbiter photos dramatically reduces the scanning defects. In addition, I designed a second filter to reduce high frequency white noise (sometimes called "grass"). Reduction of the noise allowed the pictures to be increased in contrast and adjusted to a uniform brightness level, using Adobe PhotoDeLuxe.
The pictures below show Mars as it was 35 years ago. Of course, the surface of Mars is dynamic: high winds redistribute the surface sands, and the polar caps, covered with water and carbon dioxide ices, change with Mars’ seasons. Consequently, these pictures are unique records of the atmospheric and surface conditions at the times they were taken.