Now you've done it...let me have it! let me have it!!!

OMG !! This is amazing Astro0 !! We really have the feeling of a progression now.

Oh, yes, that is a great animated gif Astro0!

Cool animation. I starred the whole day long at it, and now I think I glaciers at the Endeavour rim ... ok I starred to much.
But I hope we will get soon a third picture to this animation.

Wow! That's the first time it looks like a crater, with the foreground and background rim-mountains clearly visible in the same shot.

Hear! Hear!

Two things. First of all, just say to everyone that AJS Rayl monthly report on the rovers is already online.
Second, an extract from the named report:

I've been meaning to post this for a while now, and the recent chat has spurred me on.

I've had a go at predicting what Opportunity can possibly see, both now and further along the predicted route. I took the HRSC topo for the area, overlaid a CTX image, plonked down a marker for (roughly) where I thought Oppy was at the time (about a week ago now), and then let ArcMap figure out what's visible for something 1.8 m off the ground at that point. I then tried again for a different point along the predicted path.

So here's the base map for the area. The green dot is my poor attempt at a location.
Click to view attachment

This is what might be visible at the moment (green is visible, red, er, isn't)
Click to view attachment

And this is what might be visible in the future (from the red dot)
Click to view attachment

This method is very sensitive to both the underlying DEM and the exact location you view from. I can get very different results by moving the marker just a tiny distance. So take it with a pinch of salt, and then add a bucket or so extra for good measure. It'd obviously be loads better if I could stick a HiRISE DEM underneath, as this method worked pretty well for the Pathfinder DEM.

I'm actually hoping that the view heading down the gentle slope will be a lot better than this predicts.

Pete

Pete - chuck that Pathfinder demo of Viewshed in here as well ( I never got around to using it) - it demonstrates the power of the technique.

What Pete has shown ( for those who haven't figured it out ) is that certainly for the next several KM - we're not going to have a sudden OMFG HOAV moment - it will be a gradual progression as we've seen with Astro0's recent flicking GIF.

My kingdom for a HiRISE DEM!

Yes boss! I'll stick it over in the HiRISE DEM thread.

Pete

There are just great. Any chance you could extend the area S and SW to check out the potential visibility of Bopulu and 'south hill' from a little south of our present position?

Did we all notice that the SW flank of Victoria should still be visible? ( with deference to the pinch of salt and all that)

If we were really greedy we would ask them to animate the sequence down the drive path so we'd see green features growing and shrinking in the view from above with an in-set image showing a red dot moving down the drive path. But that would take a lot of time and all we have to offer is boundless admiration and praise.

This is really cool, Pete. I've got a couple of questions/comments. First, does this take into account the curvature of the surface?

Your results definitely look sensible along the inside of the far rim of Endeavour, presumably since the slope is quite large there. But in both plots, there are areas right adjacent to the observation point that aren't green. Why is that? I can see that the blotchiness of the green areas on the flatter areas makes sense, since the slopes there are extremely small. But it should still be green close to the observation point.

I see what you mean by the green areas changing quite a bit when you move the observation point around - again, since the terrain is so flat. I wonder if you could do a series of these plots, each time moving the obs. point around a bit (say within a 10 metre or even 100 metre region), and then take the union of all the green areas. That may eliminate the high frequency noise.

Yeah I'm troubled by the lack of visibility around the marker point too. My gut feeling is that this is all coming down to the underlying HRSC DEM, which is 75 m/px. This is probably too coarse to do a viewshed at the scale that we're interested in. But I've got to admit that this is the first real time that I've played around with this method so I'm still learning the ins and outs. Now if someone had a CTX DEM of round here...

So I'm going to have a bit of a play around and see how things change as the marker moves around. I've got a feeling that I might be 'overinterpreting the data' as they say (ie making it up!). But the idea of moving around and averaging is interesting, and if I come up with anything then I'll put it up. I might even try a little bit of MOLA as well, see if that improves things, as that's what Tim Parker's LPSC contour map used I think.

Pete

Here's an extreme vertical stretch of the hills with a bit of noise reduction from adding frames where possible.

Phil

Click to view attachment

Something dark on the skyline in this view, though likely not at extreme distance. Is there another small crater in that direction?
http://qt.exploratorium.edu/mars/opportuni...66P2368L7M1.JPG

Good catch, ngunn!
The heading is consistent with the next crater on the planned route. Here's it on Google Earth.
Click to view attachment

Wow, we've only just got here and we can already see where we're going next!

Click to view attachment

Concepcion and the Next Crater, seen at same scale, with the IAS viewer...

Click to view attachment

Can't resist...stop me please...
I hereby name you...Double Dare! Aliki & Margot...

As long as there is no HiRISE DEM yet ... here is a quick try at creating a single-image-DEM from the CTX image T01_000873_1780_XI_02S005W.
(with the whole DEM consisting of about 10 million polygons which is currently about the limit that my software's core math solvers can handle. So the next project I'm working on is to port and compile my sources into a true 64-bit application such that it can make use of the full 12 GB main memory under Vista 64 (I know, I know I should use a Mac, really -> so maybe in the near future it will be able to generate DEMs with 50-100 million polygons.

some oblique views of the area between Victoria and Endeavour:

Click to view attachment
Click to view attachment
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And the last image is how it might look like from the ground. However, I did not select a special viewing direction ... just played around with the camera position and rotation until it looked good ... ah yes, and the vertical height is somewhat exaggerated too

Click to view attachment

Just at that twin crater we might get a better view to the south(west), i.e a sign of Bopulu crater and the hills eastward of its "promontory".

Oh my, very nice...good stuff, Nirgal!

Early in this thread I suggested based on the navcams that this feature to the south was the hill far to the south. I agree it looks much too close to be that hill, which is farther than Iazu. But I'm not sure about your identification, Tesheiner. I'll call the close pair of craters you suggested Twin Craters (I guess they're not identical twins!). Measuring the angles each component (A and B ) would subtend at Conception, I find the Twins should look this big:
Click to view attachment
In other words, much bigger than the dark feature on the horizon. But looking closely, there are some dark features (black arrows) that could perhaps be one or both of Twin Craters somewhat closer than the horizon. In L2, these features look bright, which might be exposed bedrock on the rims?

Is there another feature somewhat farther than Twin Craters that the dark feature on the horizon could be?

I've been pondering these features, the farther and the nearer, for the last few hours but without having your handle on the subtended sizes. I believed Tesheiner (as one does ) but then couldn't find anything on Stu's Hirise crop that looked like the nearer features. Then again like Tman I thought the downward slope would be starting about where the twin craters are, so wouldn't have expected the ground to rise again immediately beyond. I can't be much use here but I'll stay closely tuned to learn how it pans out.

We will certainly have to keep an eye on those features once we leave this area.
Fredk is right. Althought the horizon feature is at the right heading, it's too small to be the twin craters; those ones, combined, cover about 3.5º viewed from the current position, while the black feature has only 0.4º.


Unfortunately, the HiRISE picture I'm using doesn't cover that area.

Here's a crater in about the right place.

Phil

Click to view attachment

That looks highly plausible Phil. How far away is that? Is it on our projected route?

It is about where we start to turn to the east after this long trek south and west (about 1400 m south of Concepcion).

Meanwhile, here is another look at Iazu, a comparison of two sols (cut from a post higher up in this thread). I have labelled four hills, and the way hill D gets displaced relative to the other three suggests it must be on the far rim of Iazu.

Phil

Click to view attachment

Stu's latest pic (which is a wow!) made me realize something that is stunningly obvious, but bears reflection: All of the geology @ Meridiani is completely buried. It take an impact to bring anything at all up above the sand. This is strikingly different from the other locales on Mars we've been able to see at this scale.

Why?

The soft, sulfate sandstone surrounding us at the surface is swiftly and steadily sanded smooth in the short term.
The relatively resistant, robust rocks representing the rest retain the resplendent relief remaining from the remote realm of real rheology and resurfacing.

Really

Oh, great. Now I gotta come up with a sentence featuring words that start with "Q"??!

Quiescent quiteus, queries quintessential (quixotically?)

I quit!

[EDIT: Quorrected!]

Quite.

please...

Damned if I didn't misspell "quintessential" to boot (Corrected...I hope!)! Argh. Gonna get the letter Q kicked out of the English language for good; I'll let you all know when it's done.

Please be kwik!

Now we are sicks?
http://images.google.com/imgres?imgurl=htt...t%3D40%26um%3D1

"Gonna get the letter Q kicked out of the English language for good"

Finally, a use for those defective keyboards from Dilbert.

Phil

Referring to the crater that appears on the horizon beyond 'twin craters' -



I'm still not entirely making sense of this. Using the 800m diameter of Victoria for scale I reckon we turn east less than 1400 metres south of Concepcion. Also, 1400 metres south of Concepcion would place that horizon feature below the next (downward) contour on the map. I'm aware of the limitations of the map. So I still don't know if we're going to visit that crater or not, and I'm now additionally uncertain about where the opening up of the view to the S and SW can be expected. Can anybody shed light?

Ngunn, using the proposed route we've seen from the abstract, I agree that we'd turn east before reaching the "crater beyond twin craters". But nothing stands out for that crater (it doesn't look especially fresh, eg), and I'm sure we'll encounter more similar sized ones on our trek. Of course we have to keep in mind that that's only a proposed route - we're not commited to it. Also the resolution of the proposed map isn't great.

In terms of the view, according to the contour map, the best views will be between the south and east. The rise around "crater beyond twin craters" is towards the SSW, so it shouldn't block our views towards the south to east. I don't know what kind of view we'll get to the SW (eg Bopolu), since I haven't seen a topo map in that direction.

I agree D is on the far rim, and in this post I also claimed that the bits on the right are far rim. Here's a cross-eyed version of the long baseline stereo view for those red-green challanged out there:
Click to view attachment

Right, I must have missed that! Very good. That far rim topography is the most distant we can see so far, I assume.

Phil

What's that on the right?
http://qt.exploratorium.edu/mars/opportuni...66P2368L7M1.JPG

Could you be more specific? Nothing jumps out at me.

Maybe he's referring to that faint rise on the horizon.
Click to view attachment

There appears to be a hill on the horizon extending in from the right margin for about 10 percent of the image width. It's visible in 2 of the 3 filters.

EDIT: You got it centsworth.

Looks like I'll just miss the answer - I'm off for a week's holiday now.

Thanks ngunn. Feature noticed also... Enjoy the enhancement
Click to view attachment

Comparing this with the circular pan from the other thread, this lies in the right direction to be Bopolu crater.

Phil

Here's my attempt at pulling Bopolu out of the haze and jpeg noise. Average of L5 and L7, contrast and 3x vertical stretches:
Click to view attachment
Bopolu in its entirety would subtend around 18 degrees for Oppy, while this bit's only about 2 degrees wide. So presumably we're seeing just one high part of the rim now.