Emily Lakdawalla • Aug 27, 2008
Pictures from the past: Viking 2 approaches Mars
On Monday I pointed to the awesome new website for the VMC instrument on Mars Express and mentioned that the camera can get views of Mars in a crescent phase. I thought it might be the first spacecraft to do so, but a couple of readers wrote in to tell me that they remembered crescent views of Mars from Viking 2. A Google search quickly yielded an image on Astronomy Picture of the Day from 1999, showing a tiny, garishly colored view of a crescent Mars.
Raw Viking images contain a lot of speckly noise, random missing lines, and reseau markings, black dots painted onto the camera optics to help the imaging team remove distortion from the images. Thankfully, there is a piece of software that you can download from Peter Masek's website that copes with the first two of these problems. (His site also contains a lot of background information on how the Viking cameras worked.) I used his software to despeckle and convert the original files to a format that Photoshop could read. Then I took the images into Photoshop, combined red, green, and violet filter images into a color composite, and used the Photoshop clone stamp tool to remove the reseau markings by painting over them with bits of color from elsewhere in the image. Voila, a spectacular set of Viking 2 images of Mars' looming crescent.

NASA / JPL / color composite by Emily Lakdawalla
Viking Orbiter approaches Mars
This is the final image of Mars captured by Viking Orbiter 2 as it approached for its orbit insertion on August 6, 1976. It is a two-image mosaic. Valles Marineris is clearly visible at the center of the disk, crossing the terminator. In the south, frost extends up into the Argyre basin; on its edge, with a dark outline, is the crater Galle, famous for the eroded remnants of a central ring that makes it look like a happy face.You are Part of LightSail’s Legacy
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