That's a really nice map, Pete. Thanks.

Phil

The comparison of the scale on the vertical axis relative to the horizontal gives you an idea how incredibly flat this area is. The vertical scale looks to be about 40x the horizontal scale! To put that into context, I tried resizing the elevation profile on your post to bring the horizontal and vertical axes into the same scale. Keeping the chart the same width, the vertical axis shrank down to 5 pixels high.

Here is an overview of the sightings of the still-to-be-named crater wall crater. Because it is a landmark which can be seen from a very long distance, it is interesting, how good we can see it at different positions in Meridiani Planum.

The first sighting of this crater wall I found at Sol 1954. Does someone saw it earlier? Is there an easy way to find out, if the pancam looked into the direction of the crater wall crater? I had to go through thousand pics and pick up the best ones.

At sol 2264 the crater is touching the horizon.
From sol 2300 to 2427 the crater is rising above the horizon.
After sol 2500 the crater is touching the horizon.

I have some more pics from the crater wall crater. I hope I can put it into an animation.

edit: typos.

Excellent, but I have one query. Looking at your vertical profile there does not seem to be a direct line of sight between the top of Cape York and the 'Cape York visible' point, even allowing a couple of metres for camera height. How to make sense of that??

That's a symptom of the vertical axis being MASSIVELY exaggerated.

No, just stretching one axis can't explain it. One of the axes would have to be non-linear.

A uniform vertical stretching transforms a straight line into another straight line. So ngunn is right, you should be able to connect the peak of CY to a point 1.5 metres or so above "CY visible" with a straight line of sight, regardless how the profile is stretched.

All I can think is that maybe the profile doesn't go right to the highest point of CY.

Nice compilation! The sightings of that part of the far wall (we called it "Cook" in the old days) go way back. Here's a view from 1821:
http://marsrovers.jpl.nasa.gov/gallery/all...93P2421L5M1.JPG
But we could see it from way back at Victoria, on sol 950:
http://marsrovers.jpl.nasa.gov/gallery/all...CNP2386L7M1.JPG

Yep, that would do it. Pete may have produced the profile first, then fine-tuned the location for the reverse visibility plot a little further SW to a point about 5m higher than the end of the profile. That, plus the 1.5m camera height, would be enough.

If you remove the stretch, then add the 1.5m height of the rover - then the problem goes away.

Thanks a lot, Fred. Then I just have to view 1000 sols more the next days ...

And here: The crater wall crater movie: All pancam pictures I found from sol 1954 to 2633.

Remember that if you remove the stretch, you must add the 1.5 metre height of the rover at the new vertical scale. To remove the vertical stretch, you must compress vertically by about a factor of 30. So the 1.5 metres you add after the compression will also have to be compressed by a factor of about 30 compared with the original vertical scale.

This plot shows the problem. The line of sight from the CY end of the profile ends up about 4 metres above the "Cape York visible" point, whether you plot at the original scale (above) or compressed by a factor of 2 vertically (below). Clearly it doesn't matter how much you compress the vertical scale, even 30 times. This is a useful property of maps between which the scales are linearly related.
Click to view attachment

Thanks for the movie, that's stunning. About the 1000 extra sols, if you look at the route map, we were driving more or less south or southwest until around sol 2250. So that means there are very few pancam views of Endeavour between then and Victoria, since almost all of the pancam imaging is drive-direction. The exceptions are near craters or other targets. I stored Endeavour images as we drove, so I'm pretty sure there aren't others in that S/SW stretch besides the ones you already have. But there are lots of navcam images, since they usually cover a much wider field of view.

Great visual representation there - love your DEM profiles. Please excuse my ignorance but just what is the vertical and positional accuracy of your DEM? Given the minimal vertical change compared to the distance baseline surely there would have to be wide error bars in the 'visible from' location. Shouldn't we take this as an indicative marker rather than as an absolute?

Sorry, probably a lack of information on my part. I made the visibility map first - this 'backwards' method means that I have to offset every point of the DEM by 1.5 m to simulate the camera height of Opportunity. The visibility is then determined from a series of lines all over and around what I think is the highest point (it's there or thereabouts) of Cape York. I think (still trying to get into the guts of this procedure) the actual visibility is worked out from the vertices of those lines, so it might not exactly cross the highest point itself. This is a powerful technique used for, say, checking the visibility of a road on the Earth, but I'm still getting to grips with it for Mars.

So bearing that in mind, I'd say the visibility threshold should definitely be taken as a general guide, not absolute, but on the whole it does seem to be quite close to Cape York.

I then just took a quick profile to show why that is probably the case. I'm afraid that I didn't go to the exact highest point, just through part of Cape York, so it might have led to the confusion here. So here are the raw data for a new profile going from the Sol 2635 position through the highest region of Cape York - I thought it might be easier this way if you wanted to have a look at the effects of vertical exaggeration (it really is one of the flattest places I've made a DEM of!).

Click to view attachment




Yep, worth repeating, probably best as a general, rather than asbolute, visibility marker. Plus, does that get me off the hook if it pops up much sooner than I've predicted?!

Although some DEMs have errors, especially when you're looking at things of the order of the resolution, the vertical precision of the underlying DEM in this case is pretty good. Here are the details in case you're interested. Spatially, it's at 1 m/px, made from image pair ESP_018701_1775 (26.9 cm/px) and ESP_018846_1775 (28.2 cm/px) - so about 4 image pixels to get a single DEM pixel. We can estimate the precision using the method of Chris Okubo (Icarus, 207, 2010): the stereo convergence angle between images is 14.7 degrees, so assuming 1/5 pixel correlations with 0.282 m/px in the more oblique image, the vertical precision is 0.282/5/tan(14.7) = 0.21 m.

So although it's small, we should still bear that in mind when we're dealing with these flat areas and camera heights of only 1.5 m above the ground.

Hope that helps,
Pete

The final bits of the latest colour mosaic of the rim have come down. Here it is:



James

I made a new video from the crater wall crater. I found some new pics of Endeavour, the earliest are from Sol 929, before the arrival at Victoria. So this 44 seconds movie covers a timespan of over 1700 sols on Mars! Also I found some pics of Endeavour from the Concepion crater which I integrated.

Some improvements:
- labeled pictures with sol
- removed the black parts so that the animation is a little smother

Enjoy!

MoreInput - in your movie of the crater wall crater the far landscape (in front of the wall) slides in fast manner - like you were on a moving train on earth - fascinating !
I would like change the movie to shorter intervalls between the images to see this effect more pronounced.

Robert

I got the impression they were going for a record backward drive???

According to the latest update from JPL:

"A drive planned for Sol 2640 (June 28, 2011), did not occur because a Deep Space Network (DSN) station outage prevented the uplink of the two-sol plan. The rover, instead, safely executed her on-board runout sequence. The planned drive will be recovered in the subsequent plan."

Link to Update

Did the drive happened? Are we still having problems with the DSN?

The Sol 2640 drive did not happen. I don't think the DSN is still an issue. As noted in the Route Map thread, Scott tweeted that a 5 hour drive was scheduled for June 30. I have no knowledge of whether this drive happened or not. The latest pictures on Exploratorium are garbled, but other people around here have access to other information, so let's just sit tight and wait.

It's expected to be executed on sol 2645.

Not before checking in with James Canvin's regularly updated interpretations of the tracking data.

How is it possible that I have been reading UMSF daily for three years and have not been aware of this fantastic resource? James, you are far too humble. Of course I've been aware of your blog for a long while (thanks to frequent cross-linking), but that tiny "Twitter Feed" link in your sig (which I'm only noticing now) doesn't begin to do it justice.

<Ctrl+D, Enter>

He just started in May, 2011.
Click to view attachment

I know there's folks here who'd rather I not point this out, but isn't that a meteorite out the rear window?
http://qt.exploratorium.edu/mars/opportuni...7M1.JPG?sol2643

Perhaps that's the reason to execute this long 5h drive?

Now, more seriously, this shot is part of a sequence named "Bingag Cave(s)".

Stop! Stop!! Look!! Back there!! Behind us!!! We just drove past a...

Oh, too late. *****r.



Oh well, there's going to be a **huge** one closer to Spirit Point, just you wait and see...

Another "One That Got Away"...

Click to view attachment

That's okay; someone will go get it in a hundred years or so and put it in that big cabinet in the Museum, next to all the "Islands"...

Maybe not? It's not too far behind us (I estimate around 50 metres)...

I thought they weren't going to stop at meteorites anymore anyway or did I remember that incorrectly?

Perhaps as interesting as the meteorite is the horizon differentiation behind us. The double lines suggest to me a near horizon, behind it a gentle but distinct drop-off, and then a much more distant sky/land horizon. The overall impression is of us being on gentle rise, reinforcing the earlier speculation that we will top out soon and get a revelatory view forward.

Ah so this is why I had a flurry of new followers over the weekend! I think I did mention it in passing here a week or two back, it is a reletively recent thing. I'm glad people find it useful it certainly helps keep me up to date with what Oppy is up to, something I was loosing track of before.

As for the drive that you were expecting that was planned to be at the end of the long weekend so that stuff planned in for the other days were at a known position. The drive should be happening right now...

And finally here is the Bingag Caves (?) mosaic looking back at the meteorite and the tracks into the distance.



James

Kenny, I think you're right about the two horizons. I think we are looking across the broad shallow depression which we entered just before arriving at Santa Maria. Not too far to go now!

Phil

The "one that got away" was actually visible from our previous position - here it is from sol 2635:
Click to view attachment

Have a look at this Sol-2628 navcam:
http://qt.exploratorium.edu/mars/opportuni...3QP1725L0M5.JPG
The crater on the right part of the image near the horizon....is it Santa Maria? Navcam has 45x45 degree field of view (1024x1024px). This crater is about 30px, so it is about 1.32 degrees wide. Assuming it to be about 89m then if I'm correct it gives me distance of 3862m. Google Earth tells me 3888m.

My guess would be the Mercury cluster, which is smaller but closer.

Done. 121m in "blind" mode from 10:15 to 12:00 plus 41m in "autonav" mode from 12:00 to 14:37.

At this pace, we should have a "vision" by Bastille Day...

Ah. Missed that 'cos of NLC-watching sleep deprivation...

All right, we'll let it go this time, Stu!

I've been wondering if we'll notice changes in the bedrock as we approach Endeavour. Recently I've been noticing many examples of "rind" features, like on the foreground bedrock here:
http://qt.exploratorium.edu/mars/opportuni...0M1.JPG?sol2645
We've seen these since way, way back, but they now seem to be getting more prevalent.

Could the team be referring to those features with "Bingags Caves" ?

You can just make out that crater on the distant hills in this view, and it looks like we have sunk even lower!

http://qt.exploratorium.edu/mars/opportuni...T3P2356R2M1.JPG

Yep, we've sunk about as low as we can possibly go...

Phil

Click to view attachment

Hey, cool... now Oppy's looking for meteorites beneath the dust!

It's from the book "Thirty Thousand Leagues Under Meridiani Planum" ...

Umm - a fall of Mars Dust, or maybe even Mars is a Harsh Mistress ? +
Mike

Another meteorite ?
http://qt.exploratorium.edu/mars/opportuni...T3P1777L0M1.JPG

From Scott: "Grr. Too many data products on Opportunity today; no driving. Heroic efforts will probably salvage drive for tomorrow, so that's something"

and then: "Indeed, tomorrow's drive has been salvaged through careful work, giving Jeng and Joe a chance to set another record. :-)"

May be one day short of the HOAV or whatever it'll be

It's the dreaded Sand-Rover!