[X] My Assistant

[RNeuhaus]

Oh, and I can smell sausages burning!

and some sulphide salt oxidation smelling.

Rodolfo

[Bob Shaw]

Bob you aren't supposed to use "pyr*midal structure", "many f*ceted" and "beac*n" in the same paragraph here. "They" will surely be along any moment now with theories of aircraft hangars and such.

Can I mention s*usages, then?

Bob Shaw

[centsworth_II]

Can I mention s*usages, then?

Yes, but not f*ying s*usauges.

[Shaka]

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

That's O.K., Dilo. If we don't act fast to rescue this topic from frying sausages, things could get really ugly! (Emily might even complain. )

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).

How tall do you think Beacon must be? If it's on or near the north rim, as your trigonometry implies, it does not have to be very tall. It seems to have changed very little in your sequence of pancam images. If it were on the far rim it should be getting smaller in height, since we are presumably descending, with more of it being hidden by the near rim. (Unless we are viewing it through a deep notch, which I don't see along that line.)

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).

I hate to say it but I don't think we can take it on faith that JPL has got it right.

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.

I think this is a key point. Beacon appears perched on top of the near rim. If that were an optical illusion, it should have changed over past weeks as our viewpoint has moved laterally and downward. Since it has not changed, beacon must really be on top of the near rim.
So why can't we see it in the MOC plan view? That gets back to the real size question. If beacon were a slab of evaporite say 2 by 2 meters and half a meter thick - with blown sand or dust on the top - Would there really be much to see from orbit? From Oppy's location we would see the bright clean edge, but not from overhead.
Keep on truckin'! Keep on thinkin'!)

[Joffan]

Actually one of the reasons I favour the far rim location is that the beacon used to be 5 pancam pixels high, and now it's only 1-2.

[Shaka]

Actually one of the reasons I favour the far rim location is that the beacon used to be 5 pancam pixels high, and now it's only 1-2.

Holy Cow. ( I assume you're comparing images with no vertical stretch.) It would be a huge help to me if you could link or thumbnail images that bring this change out. I didn't see it.

[bergadder]

My money is on the far rim. I think what we are seeing (based on Dilo's triangulation) is the far rim seen in a gap in the near rim. I do not think its a single tall structure but nothing more than a "lensed" or windowed view of a long exposed face on the far rim viewed through the near rim. Each view we have seen over the last few sols is thus a small section of the far rim, but not the same section, as exposed as we move south.

[centsworth_II]

I think what we are seeing (based on Dilo's triangulation) is the far rim seen in a gap in the near rim.

The problem I see is that any deviation of Opportunity from the ideal line of sight through such a gap should block out the view of the far rim and extinguish the beacon. If the gap is wide enough to prevent this, the beacon should widen or narrow depending on how well Opportunity is lined up with the gap. But ever since the beacon was spotted, it has maintained its presence and size despite opportunity's deviations from a straight-line path to it.

Any chance of getting the rover drivers to take a hard left or right and drive as far as it takes to get an unambiguous answer by parallax?

[Joffan]

At my post on 2 May I had this unstretched image of the beacon:

[attachment=5405:attachment]

and now the poor litte thing has shrivelled away to nothing - pancam, 14-May, no stretch:



- maybe it's cold...

Edit: Odd... I can see the previous image in preview but not in the thread

[centsworth_II]

At my post on 2 May I had this unstretched image of the beacon...and now the poor litte thing has shrivelled away to nothing...

I don't know how valid a comparison of these two images is. The May 2 one (on top) is a particularly wormy jpeg and I don't know if the scales are the same. Are they crops of individual pancam images or of mosaics?

If there is real shrinkage, it could as well be the result of a small topographic rise in front of a near rim beacon.

[Joffan]

The contrast is pumped up a little more on the 2 May image, but they are both original scale cropped from exploratorium images. That's why I said unstretched.

[Shaka]

I really would like to hear from the other imagery maestros about the changes that have occurred in the dimensions of Victoria Beacon since we first saw it. Tesh, Dilo, Doug, Rodolfo, and anyone willing to chime in?
Come on lads! Either you trust your own eyes and your technology or you don't... What's it to be?

Edit note: Out of courtesy and respect I will add hortonheardawho to the above list. I understend if he feels constrained to reply at another node in this miraculous global internet.

[centsworth_II]

Come on lads! Either you trust your own eyes and your technology or you don't... What's it to be?

Yeah, how long are you going to let us wallow in the dust? And how is that request for a right angle drive (to the beacon sight line) coming?

The contrast is pumped up a little more on the 2 May image...

No image expert I, but couldn't boosting the contrast on such a noisy image cause a false enlarging of a light spot?

[prometheus]

Based on this:
http://gallery.perfext.com/displayimage.php?album=2&pos=70
and this:
http://gallery.perfext.com/albums/userpics/10001/vc5.jpg

I put together this:


At least the dark rays on the left side match up. The creator (A1call on the Yellow forum) feels the elevated far hill is real but not as high as indicated.

The images suggests the beacon is not on the crater rim

[Shaka]

The images suggests the beacon is not on the crater rim

Nor is anything else visible in the pancam images, if I read you correctly.
Between the "dark rays" and the background hills (a small far hill, a large far hill, a larger far hill, and a far far hill), Victoria Crater is sunk into an invisible... an invisible...abyss?

Paging Dr. Ustrax..paging Dr. Ustrax...pick up line 3 please...