Mars Global Surveyor
Mars Orbiter Camera

MOC Images "The City Square" in Cydonia

Mars Global Surveyor Mars Orbiter Camera Release:          MOC2-45A, -45B,
                                                           -45C, -45D
Mars Global Surveyor Mars Orbiter Camera Image ID:         577826559.25801
                                                           P258-01 (WA image)
                                                           P258-03 (NA image)
See also:
MOC Views Another Area in Cydonia
MOC views the "Face on Mars"

Shortly after periapsis 258, the Mars Orbiter Camera (MOC) acquired its third view of the Cydonia region of Mars. The JPL-designated target was centered approximately half-way between two large pyramidal hills. The targeted image dimensions were established as 1024 pixels wide by 9600 pixels in length; the full width of the detector was used, thus maximizing the cross-track dimension. The image planned (and executed) image was approximately 3.5 km (2.2 miles) wide by 33.2 km (20.6 miles) long. Image resolution was about 3.5 m (11.5 feet) per pixel.

MOC images are usually planned to be as long as possible, in order to accommodate downrange uncertainties in the orbit. Prior observations were based on orbit predictions that were only a day old, and the correction for timing uncertainty was about one-quarter of the frame length. Recent, larger variations in the uncertainty of downtrack position were seen in the Viking Lander 1 and Pathfinder observations. The Cydonia image timing (start position) was compensated based on these most recent variations. The offset position of the acquired image (see below) resulted from a less-than-anticipated prediction uncertainty. This example illustrates one of the difficulties associated with targeting the MOC.

Screen-dump of Actual Target Location from Targeting Software (GIF = 122 KB)

New MOC Data

MOC 25803 was acquired at 12:23 PM PDT on 23 April 1998. The image captures an area called by some "The City Square." Image (B) is MOC 25801, a red wide-angle image, with the location of the narrow angle image marked by a white box. Image (C) is a processed version of MOC 25803; the raw and JPL-processed versions may be viewed and downloaded from JPL. Image (D) is an section of MOC 25803, showing the "City Square."

Viking Orbiter 027A63 showing outline of area imaged in MOC 25803 (GIF = 413 KB)



Some browsers apparently are unable to view large MOC images. If your browser cannot read this image directly, download it as a file and open the file in an image viewing or processing program.

JPG = 1.53 MB
GIF = 8.1 MB

These images should be corrected for the gamma of your monitor to insure proper viewing

Processing performed: pixel-to-pixel instrument variation and gross detector shading, pixel-to-pixel averaging to reduce noise, spatial-frequency filtering to enhance fine detail, and contrast enhancement.

Note that the raw, unprocessed data are available at:

Section of MOC 25803 showing "The City Square" (GIF = 177 KB)

This section of MOC 25803 shows an area believed by some to be the centerpiece of a geometric network of artificial structures within the Cydonia region, one of which is the "Face on Mars".

Note: The MOC images are made available in order to share with the public the excitement of new discoveries being made via the Mars Global Surveyor spacecraft. The images may be reproduced only if the images are credited to "Malin Space Science Systems/NASA". Release of an image does not constitute a release of scientific data. An image and its caption should not be referenced in the scientific literature. Full data releases to the scientific community are scheduled by the Mars Global Surveyor Project and NASA Planetary Data System. Typically, data will be released after a 6 month calibration and validation period.

Click Here for more information on MGS data release and archiving plans.

Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

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