Martian Morse Code
Martian Morse Code
ESP_044675_2580  Science Theme: Seasonal Processes
These dark dunes are influenced by local topography. The shape and orientation of dunes can usually tell us about wind direction, but in this image, the dune-forms are very complex, so it’s difficult to know the wind direction.

However, a circular depression (probably an old and infilled impact crater) has limited the amount of sand available for dune formation and influenced local winds. As a result, the dunes here form distinct dots and dashes. The “dashes” are linear dunes formed by bi-directional winds, which are not traveling parallel to the dune. Instead, the combined effect of winds from two directions at right angles to the dunes, funnels material into a linear shape. The smaller “dots” (called “barchanoid dunes”) occur where there is some interruption to the process forming those linear dunes.

This process is not well understood at present and is one motivation for HiRISE to image this area.

Written by: HiRISE Targeting Specialists (narration: Tre Gibbs)  (29 June 2016)

This is a stereo pair with ESP_045334_2580.
Acquisition date
06 February 2016

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
316.4 km (196.7 miles)

Original image scale range
36.6 cm/pixel (with 1 x 1 binning) so objects ~110 cm across are resolved

Map projected scale
25 cm/pixel

Map projection

Emission angle

Phase angle

Solar incidence angle
58°, with the Sun about 32° above the horizon

Solar longitude
105.4°, Northern Summer

For non-map projected images
North azimuth:  89°
Sub-solar azimuth:  317.8°
Black and white
map projected  non-map

IRB color
map projected  non-map

Merged IRB
map projected

Merged RGB
map projected

RGB color
non-map projected

Black and white
map-projected   (1281MB)

IRB color
map-projected   (725MB)

Black and white
map-projected  (598MB)
non-map           (411MB)

IRB color
map projected  (209MB)
non-map           (331MB)

Merged IRB
map projected  (358MB)

Merged RGB
map-projected  (340MB)

RGB color
non map           (318MB)
Map-projected, reduced-resolution
Full resolution JP2 download
Anaglyph details page


B&W label
Color label
Merged IRB label
Merged RGB label
EDR products

IRB: infrared-red-blue
RGB: red-green-blue
About color products (PDF)

Black & white is 5 km across; enhanced color about 1 km
For scale, use JPEG/JP2 black & white map-projected images

All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible:

NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA’s Science Mission Directorate, Washington. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.