[X] My Assistant

[Bob Shaw]

Doug:

I'd sorta worked that out in general terms - however, the time of year on Mars will change the illumination to some degree. Perhaps some lines on a map exist, somewhere? (hint!)

Bob Shaw

[chris]

For the informal poll, I think we are seeing the near side of the crater. I would be expecting to see more evaporite if we were seeing the far side.

Chris

[MahFL]

I say far rim.

[RNeuhaus]

The beacon is on near rim. I relay to the wind prevalence and image colors to deduct the position of beacon. Clear color is far ream and dark color is of near ream. If the near rim is higher, then the impact meteorite would comes with a southern angle.

The image is still blur at this distance. What distance wouldl the PANCAM image become clear enough to distinguish the near/far rim?

Rodolfo

[lyford]

I think we'd argue that one to death - because it's basically a pixel or three - and I can imagine someone arguing that those pixels had a contribution from near and far rims together as the crater resolves itself.
Doug

Well, on other some sites 3 pixels would be evidence of a whole civilization....

[centsworth_II]

...it's basically a pixel or three - and I can imagine someone arguing that those pixels had a contribution from near and far rims together as the crater resolves itself.

No detail from the pixels forming the beacon, but a precise position. Is Tesheiner the only one who has studied the parallax changes as Opportunity angles away from a straight line drive to the beacon? I think that is currently the most powerful argument and not hindered by even a one pixel beacon. I'd like to see others more adept than I do the calculations and support or rebut Tesheiner's position.

As far as a near and far rim contribution to the beacon, I'd say 'no way'. Surely with even a slight deviation from a straight-line path by Opportunity, a separation of the two points (near and far) would be seen, even if they were an one time alined.

Intuatively, I see the beacon as the tip of a prominence on the far rim, but Teishner's parallax argument, if supported, would make me agree that it is a near rim point. In fact, may it not be a chunk of rock laying out on Victoria's apron, tens of meters from the edge?

[Tesheiner]

No detail from the pixels forming the beacon, but a precise position.

That's exactly the point. The beacon could be a whole 100x100 pixels feature with a lot of detail but what's really important is not *how* it looks but *where* is it located (the angular separation) in relation to other known features.

[helvick]

I'd sorta worked that out in general terms - however, the time of year on Mars will change the illumination to some degree. Perhaps some lines on a map exist, somewhere? (hint!)

As will the time of day obviously. For thissol for example sunrise azimuth is 70.0deg (at 06:02 LTST) and sunset is 290.1deg(at 17:58 LTST) while at 10:00AM LTST it's 51.7deg.
If you don't want to do the calculations yourself Mars24 shows them all quite nicely on the Local Panorama display, you just set the location, date and time.

[dvandorn]

I think the hummocky terrain on the right side of the now-emerging "Victoria Complex" is a near-rim feature. In specific, I think it is the planview of one of the lobe-shaped overhang features we see in the orbital, overhead views of Victoria. It appears that some of these lobe-shaped features have topography of their own, and are not simply mass-wastage forms resulting from rim collapse and expansion. (That makes them a lot more interesting, in my book...)

As for the beacon, I must rely upon the analysis presented heretofore in this thread. It would seem that the beacon is a near-rim feature. But we're far too far away to have any other information about it.

Since we're able to pinpoint it as a near-rim feature from parallax information, can we use that information to at least constrain its location on the near rim? I have seen a few speculations here, but we're not even presenting images of Victoria in a standardized way -- some use the north-is-up convention, others try to place Oppy's current drive direction as the 'up' vector... I can't get a good handle on where on the near rim the beacon might be located.

-the other Doug

[imipak]

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.

I'm for 'near', fwiw. I think the dark area some way to the left of the Beacon is the wind-deposited 'tail' that emerges from the downramp, and that we're looking at the raised nearside rim.

What makes this fascinating is that AFAIK, no-one can claim to be absolutely 100% positive - we're still within the margins of error for parallax at this range (I think?) How about a follow-up poll about the number of Sols before everyone agrees with one option or the other? I vote for a long period of ambiguity, say... Sol 850.

[dilo]

I made my personal attempt to measure beacon parallax, but results still confusing me...

Starting from PanCam stitches and assuming an angular scale of 0.28mrad/pixel, I found the following angular distances between the beacon and east (left) rim of "corner crater":
Sol pixel deg
796 525 8,42
800 581 9,32
803 597 9,58
813 689 11,05
815 735 11,79
818 744 11,94

Then, using Theseiner route map, I reported azimuth of beacon for each Sol (blue lines):

Incredibly, the "least distance" between these headings lie in a point closer than Victoria (orange ellipse) ; this could be due to error in stitched images and route map and, anyway, the "near rim" hypothesis seems to be favorite. However, in the portion of the rim where we should have the beacon, I do not see any clear feature suggesting such a tall structure... (see enlargements of original and "press release" pictures of this region).
On the other hand, headings matches enough with "far rim promontory" suggested by JPL, even if last heading (Sol818) seems to point to another adjacent structure (to the right of it).

At this point, the only matching explaination seems we are seeing the far rim trough a hole in the close rim, as already suggested by someone... however, also this odesn't satisfy me because:
i) we should see some change in the beacon appareance due to parallax
ii) the beacon appear clearly elevated in all images.

See following collection referred to the Sol numbers reported at the beginning of the msg:

[Joffan]

Good job dilo...

and, get real, guys. A big white triangular promontary? It's the far rim.

On one shot a little while back, when I posted a stereogram, the right eye picture showed the beacon and another spot of white a little further along. I wonder if we have seen the second beacon sometimes?

[Tesheiner]

Great work, Dilo.

I'm also puzzled by the lack of evidence of a clearly visible feature at the near rim on MOC images, but for the time being I should keep with the "near rim" hypothesis because the apparent "drift" of the beacon location on VC's far size, imho rules out the far rim option.

But to be sure, we should better wait for some 200m driving south and do again the same exercise.

[Bob Shaw]

The beacon is obviously going to be a roughly pyramidal structure, twice as high as a man, set in the rock like a gigantic, many-faceted jewel. Oh, and I can smell sausages burning!

Bob Shaw

[ElkGroveDan]

The beacon is obviously going to be a roughly pyramidal structure, twice as high as a man, set in the rock like a gigantic, many-faceted jewel. Oh, and I can smell sausages burning!

Bob you aren't supposed to use "pyramidal structure", "many faceted" and "beacon" in the same paragraph here. "They" will surely be along any moment now with theories of aircraft hangars and such.