[X] My Assistant

[sranderson]

This base image (which was posted by Dilo earlier) isn't 100% correct, but I've annotated it to show suggested lines-of-sight that seem to support the contention that we are looking at the far rim of Victoria.

FWIW.

--Bill

The problem is that the MOLA data is "blurry" to the point of total abstraction. If it had more resolution, it would show the slope leading up to Victoria, the rim, and the crater itself -- but all it shows is a blurred depression sorta centered on Victoria. In reality the whole depression is inside the rim.

[dilo]

Must agree with helvick, these data aren't very reliable (the middle step is an artifact due to unmatched datasets and also VC slope do not seems realistic).

In the meantime, using Registax, I made this "super-res" image of the beacon based on Sol815/816 PanCam images (total of 4 frames):

(150% of original scale)
The features highlighted by Ustrax aren't evident ( ) while the dark patch on the right is clearly visible...
This structure is about 2 pixel tall, a little bit more than 1 meter assuming that is located on the far rim and only 75cm for the close rim...

[Bill Harris]

Yeppers, the MOLA data is horrid _for this application_. But it shows that the terrain goes from a topographic high of x-magnitude at Oppy's current location to a low of y-magnitude at Victoria and strongly suggests that it is possible that we could be looking at the nether side of Vicky. Even if the rim were horizontal instead of "tilted" it would still be possible to see the other side.

So there.

--Bill

[Tesheiner]

I'm still not sure but I would appreciate comments on the hypothesis

Given that picture I would agree with you, those matchings are quite convincent; actually I had the felling too that we were looking into the crater itself.
I did an exercise (see below) to find the correspondent points on the near rim for each point you selected on your image, and try to match them with the pancam views. No conclusion at all. If that was the only data I would say "far rim".



BUT after doing the other exercise of measuring the angular distance between the beacon and corner crater for both near and far rims scenarios (*), those results pretty much convinced myself that the beacon is at the near rim. It can't be at the point we see it today if located at the far rim (if my math was correct, of course ).

(*) I'm looking forward your (or anyone) review of it.


And yes, this "mystery" may be solved in a week or two.

[djellison]

Doug, I would like to know why you think we are seeing the near rim...

Umm - because I think what we're seing is hte near rim and not the far rim. I might very well be wrong - but at the moment I think we're seing the near side of the crater - not the far side.

Doug

[Shaka]

My position remains unchanged. If we now had an unobstructed view of the far edge of the crater, we should see a panoply of bright white reflections from the edges of the evaporite (not just Beacon), interspersed and underlain by hard, black shadows, not just diffuse dark areas. Everything is sort of smudgy-dark because we are looking at a relatively featureless surface sloping away from us - the near apron of Victoria. If I'm wrong, I will bake a hat-shaped cake and eat it.

[Phil Stooke]

I'll join you in a slice of that hat, Shaka. This has to be the outer rim on our side of the crater.

Phil

[dilo]

Bill, I understand your point about altimetry... it seems reasonable, but I see that the majority still in favour of near rim hypothesis (and I'm still uncertain!).
Let's see in the next few weeks...

[Bill Harris]

Then I'll give you a definite maybe to all the above.

But, as you say, we'll know for sure in a few weeks.

--Bill

[marswiggle]

Sure I know that VC is confusing but never imagined that speculations would run this wild...

While it's always good to propose new ideas, I anyway give my provisional verdict in the Victoria Crater case:

Victoria seems to be a 'rimshot' crater herself, or more precisely, shot just inside into what's possibly 3--5 times larger paleocrater. The VC impactor happened to hit the ~NW sector of this shallow depression, which is why the NW portion of Vicky's rim rises higher than the rest. The 'beacon' must be the highest point there, let's say 10 m above Oppy's level. Oppy is approaching from NNW and thus can't see the interior. But she can see part of the paleocrater (the depression to the left) and distant dunes on its opposite 'slope' (pancam sol 817), and probably marginally over the left edge of VC. The stretched images revealed that the horizon in this ESE direction is bent slightly down from the expected level, so it must be really far away (and the depression large). This makes sense also if the peaks on the horizon belong to the rim of the more distant SE crater (35 km), as others have stated.

Owing most of these deductions to others than myself, I refrain from further speculations on the features of VC until Oppy arrives at the near rim.

Call this image a wild speculation. (Orig. [corrected] R1400021, cropped and reduced to 50 %, south up)

Attached thumbnail(s)

 

[djellison]

I've figured out why I think it's the near side of the crater.

The features are running down and to the right - which is what I'd expect if we were looking at the western half of the near side rim because of the slope. If they were on the far rim, then I'd expect them to be running down and to the left.

Just my 2p's worth - but hey - we'll only find out in a couple O months

Doug

[centsworth_II]

If we now had an unobstructed view of the far edge of the crater, we should see a panoply of bright white reflections from the edges of the evaporite (not just Beacon...

By the same token, if the entire near edge of Victoria is in view, why no panoply of bright refections from it? If the beacon is on the near side, it would be a unique, small feature -- perhaps a lone boulder rather than part of a continuous outcrop. If it is on the far side, it would only have to be the tip of the highest outcrop. If parallax calculations show that it cannot be a single point on the far side I would have to respect that.

[RNeuhaus]

I am still not sure of any of them (north or south) rim.

However, I feel that the indicated arrows are of near rim.

I see the black features corresponds to near rim and not of the far rim. Not sure because the image is still blurr.

The selection of near rim was based on the following deduction:

The prevalent wind comes from SouthEast to NorthWest. Hence, I suspect that the far rim (southEast) would be mostly covered by sand (light color) and the near rim (northWest) has strips or streaks of winds and hence the land is somwhat darker. According to my desert experience, the wind deposits sand or powder on the falling of hole and cleans the hill and its post after the wind leaves the surface of a hole.

The other hypothesis, if the meteorite that hit Victoria Crater comes from NorthWest and the tallest part of rim should be on the SouthEast. That is that the rim would be of far side. This hypothesis contracits to the previous. However, as I see VC as almost circular and not as an elagnoted shape made by a coming impact meteorite direction.

I am still peeling off the leaves of a flower.

Rodolfo

[Shaka]

By the same token, if the entire near edge of Victoria is in view, why no panoply of bright refections from it? If the beacon is on the near side, it would be a unique, small feature -- perhaps a lone boulder rather than part of a continuous outcrop. If it is on the far side, it would only have to be the tip of the highest outcrop. If parallax calculations show that it cannot be a single point on the far side I would have to respect that.

The "edge" (the broken sides of evaporite layers) on the near side face away from us to the south, so they are only visible to observers south of Victoria. We are looking at the crater apron (and its coating of sand, concretions or whatever) up to the break point. The "edge" is out of sight. The white and black panoply is hidden from view.
"The beacon" is something special, and requires a special explanation. You offer two, others have been mentioned: A view of the bright far edge through a gap in the near edge (like the "boat ramp"), or a section of white edge with an adjacent darker turned-down section (also on the far edge) which therefore move together despite parallax changes. I'm eagerly awaiting each day's pancams to see if it disappears.
One thing I'm sure of: thank heaven for the Beacon! Without it what would we have to argue about?

[Guest_Bobby_*]

I would like to start an informal poll regarding Beacon Rock or Outcrop ending on May 20 when we might know where it's located at? Is Beacon Rock on the near rim or far rim? I will say far Rim. I will log the votes daily and see what everyone thinks.