August 29, 2007, HiRISE release Options

[Guest_AlexBlackwell_*]

August 29, 2007, HiRISE release

Interesting new image of the Arsia Mons pit.

The polar pit gullies image is pretty good, too.

[Hugh P]

Moved to correct thread - Mod

No one seems to have noticed details in this pit -


I tweaked the levels in Photoshop and applied a slight blur to reduce the scan line artifacts, and tweaked the levels again.
It seems that there an extra shelf below the eastern wall, which may be an overhang or even a tunnel, or more likely rubble that's fallen off the eastern wall.
There's a shadow gradient from top left to bottom right which cannot be a camera artifact, and is either caused by the slope and/or from the light reflecting off the opposite side wall.

There also appears to be chunks of rubble at the base of the pit, although this may well be in part noise from the HiRISE camera. See this image to compare how light plays off rubble in the bottom of a pit, and it seems fairly similar. However the gradient is in the opposite direction possibly because this hole is shallower relative to the width.

I'm very surprised no one has spotted this before as it had quite widespread media coverage when the image was captured in 2007 and I have been unable to find any other reference to this. Here is the link to the HiRISE source - the details are only visible on the non-map projected image.
Here are the original musings about it on my blog and I would be very interested to know what the experts think