Clouds drifting across a martian sky…

The ever eagle-eyed fredk over on the UMSF forum spotted earlier today that Oppy has sent back some navigation camera images showing clouds moving across the sky above Endeavour crater. The raws are a bit light to show the clouds properly, so I fiddled about with skilfully manipulated them using Photoshop to bring out more detail, then added them together in sequence to make a short animation, which I post here for your enjoyment (I hope!) Not sure if you’ll need to click on the image to bring up the animation, but if you can’t see the clouds moving as you’re reading this then you’ll have to do that, ok?

Now, obviously that’s speeded up, a lot, but just imagine standing there beside Oppy and looking up to see those wispy bands of cloud drifting silently across the sky above Endeavour… 🙂

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6 Responses to Clouds drifting across a martian sky…

  1. Matt Lenda says:

    This is unassailably cool.

    I guess we call it the “cloud movie” sequence for a reason, eh?


  2. Buck says:

    Very. Very. Cool.

  3. rickyjames says:

    Look closely. There’s a moving dot in frames 2 and 3 – Phobos or Demios? Perhaps that’s the reason the science teamt took these pictures…

  4. rickyjames says:

    Additional thoughts I posted over at Unmanned Spaceflight:
    Consider what is being said about this sequence of four cloud images which have six dots of light in them, four of which are identified as Phobos. Each frame of the four frame sequence is 512 by 512 pixels in size. Denote the lower left pixel as being at X=1, y=1 to define a standard Cartesian coordinate plane. Shooting the sequence at an azimuth of 66 degrees implies that the 66 degree heading is aligned along the vertical column of pixels in column 256. Look at the four dots of light visible in the upper right corner of the sequence. This is said to be Phobos descending nearly vertically in pixel column 448 at an azimuth or heading of 87 degrees. That’s a heading difference of 87-66=21 degrees in 448-256= 192 pixels for a scaling factor of around 0.109 degrees per pixel. Between frames 3 and 4 Phobos moves down about 14 pixels which would correspond to 14 * 0.109 = 1.5 degrees in the sky. If Phobos is sinking at 3 / 4 or 0.75 degrees per minute as specified in the forum discussion then these last two frames in the cloud sequence were taken two minutes apart.

    Now look at the two mystery dots that appear to be “flying” from right to left in frames 3 and 4. Assume for a moment they are two images of the same object instead of two random cosmic ray pixel glitches. Note that if Phobos is descending anti-sunward in the east in the images, then the right-to-left motion of our mystery object means it is moving from south to north, over the poles –a reasonable path of motion for a science orbiter from Earth like, say, Mars Odyssey with its inclination of 93.2 degrees.

    Also, the “mystery object” changes its position by around 230 pixel units or 25 degrees in the field of view using the scaling factor defined above, and it does so in the two minute interval between frames. Horizon-to-horizon is 180 degrees, so at constant speed this mystery object would have appeared to go from horizon to horizon in (180/25)*2 = 14.4 minutes.

    Huh, Mars Odyssey is used for 15 minute communication passes with the MER landers. See Step 18 at this NASA website:

    So if the two mystery dots in this image sequence ARE cosmic ray glitches, they are glitches that ACCIDENTALLY mimic BOTH the expected direction AND expected speed of an orbital communications satellite that we know is being used by the rover.

    Another point: are there statistics showing that two cosmic ray pixel glitches of this magnitude per every four images is routine? If not, then these are REALLY amazingly coincidental cosmic rays.

    As for the “it would never be visible” argument, remember that Mars Odyssey or a Mars polar orbiter like her have got something Phobos doesn’t – solar cells that can reflect solar glint. That’s why we can see the Space Station from Earth on the ground as a bright star (usually right at sunset when the observer is in just entering darkness and the station is in still sunlight) as well as the infamous” Iridium flares” that can make a satellite in earth orbit appear as an incredibly bright -8 magnitude object in the sky.

    So once again, I ask: Does this cloud image sequence show not only clouds, not only Phobos, but an orbiter from Earth as well? Can somebody check the location of the various Mars orbiters when the shot was taken?

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