May 23, 2007, HiRISE release Options

[ustrax]

I'm saying it's impossible to say "that's the bottom".
Lest we forget, similar techniques turned a black dunefield into all sorts of things.

Neither am I, I was not saying "look how dark is the bottom, it might even be a pond!"
I was focusing on the "walls"...
For now...

The problem of that dunefield was being a dunefield, let's remember that the techniques applied to Ultreya were accurately developed specifically to deal with an abyss...

EDITED:

...the upper part of the circle is lighter than the lower part. This might be the floor showing.

Yes, I found that curious because it seems to be an extension of the disturbed lighter soil patch outside the hole:

[akuo]

Binning done in the electronics before AD transformation is a lot more effective than in software, and I think this is what they talk about when some Hirise image is 2x2 binned etc.

Increasing is exposure time is of course problematic because Hirise has a scanning type detector. It will be interesting to see what the future plan is.

[centsworth_II]

Will we have to wait until there is a laser altimeter or radar that can look to the bottom? How soon
can that be? I'm guessing a camera sensitive enough to see down there would not be worth it.

[Tesheiner]

... similar techniques turned a black dunefield into all sorts of things.

True. But we had good times imagining what "those sort of things" might be.

[Juramike]

It's not an abyss, it's a martian oubliette!

And when we finally get illumination down there we'll find both Mars Polar Lander and Beagle 2 at the bottom!



( "My God, I see stars....")





[This image has totally tickled me pink. Aside from it's sheer image impact, a collapsed lava tube is a great way to get a peek at relatively protected Martian basalt.]

-Mike

[Gray]

Note: I know that it has already a name but Cernunnos, the Celtic God of Fertility, Life, Wealth and the Underworld sounded just perfect for the occasion...

Perhaps we could we could use the name 'Cernunnos' for the underground chamber(s) for which there may be more than one entrance.

[Stu]

Maybe one day...

[tuvas]

MRO flight rules limit the off-NADIR pointing to 30 degrees. But that's only 24 degrees difference, it might allow one to see the bottom of the cave. It would almost certainly allow seeing the wall of the cave. Still, this is turning to be a highly unusual feature.

Oh, SHARAD might be able to find the depth of the cave, I'm just guessing though.

Also, you might be interested in knowing that the HiRISE team talked about the cave in a HiOPs meeting last Monday, we were joking that MSL should repel down into the cave, and then we thought, well, it can already repel, skycrane... Hmmm...

[ustrax]

Regarding the "work" I've done with the image, Alfred McEwen told me that it may be "scattered light", "the camera optics are excellent but not perfect."
But, might I add, the closest to perfection I have ever seen...

[ngunn]

Thinking about the possible pattern of illumination in the cavern made me think again of that wonderful Pantheon photo. The patch of sunlight in this case might be falling on a horizontal floor, but more likely somewhere part way up one sloping side of the tunnel, thus preferentially illuminating the opposite side with scattered light. I have a sketch of the geometry which could produce the apparent slight grading in interior illumination that may be showing on that image, but unfortunately no easy way of posting it here.

[ngunn]

Ouch!

Am I the only one that didn't immediately see the pun??
GROAAAAAAAN!

Actually you saw it before me, so - it was all in the eye of the beholder! (Maybe a case of the pot calling the kettle black? How appropriate.)

By the way I'm going to be incommunicado for a few days - probably just as well.

[ustrax]

I've made a new animation focusing on the top-right quadrant.
Noise? Scattered light?
I just love the way the appearing features, layers-like, matching so nicely with the rim, seem to belong there...

[tedstryk]

Perhaps they could rotate the spacecraft to compensate for motion, allowing longer exposure times (same principle as CPROTO with MOC, but using the reduced speed at which the surface goes by for longer exposure time per line instead of higher resolution. Would be difficult, but worth trying once if at all possible.

[marswiggle]

I had a quick look in the MOC Gallery for similar features around the Arsia flanks and happened to find these. The first one is clearly Dena, from here. The second one is from here (lower right of the narrow angle img), and AFAIK it has not been referred previously. Both images are full size crops from the gif files, so I think the sizes are ~about~ proportional. The second one certainly could be an artefact, but it is very similar to the other ones anyway. A thorough search in the MOC imagery could reveal more.

[ustrax]

I had a quick look in the MOC Gallery for similar features around the Arsia flanks and happened to find these.

They may not know yet what happened to their loved one but let's have some respect by Bwwn family's privacy...