Post Conjunction: Santa Maria to Cape York, The Journey to 'Spirit Point' Options

[fredk]

I've been intrigued by a little feature on the horizon. You can see it in the latest pancam view:
http://qt.exploratorium.edu/mars/opportuni...2M1.JPG?sol2603
Here's an average of the L and R frames from sol 2603, with a nearby crater, "A", and the horizon feature, "B", both marked:

I've identified crater A in the following orbital view:

I've also given a tentative ID for feature B, as a very distant crater. The relative lines of sight are correct between A and B. Still, there are a couple of other candidates for the horizon feature, marked C and D. I'm going with the distant crater, B, because it looks like it has more relief than C and D, and because the horizon feature looks very far away. I think B is what Stu called "Cape approach crater".

Anyway, this is very interesting, because as you can see, my candidate for B is getting pretty close to Cape York. I don't think the horizon feature actually is a part of CY, though, since I figure that the highest point on CY should be farther to the left.

[Stu]

Wow, that would be a heck of a thing, wouldn't it? If you're right (and you usually are!) that crater is on Cape York's dorstep. Actually, it's the newspaper left on Cape York's doorstep. Amazing.

( I've missed the past few days' developments, was on camping trip/SAS survival training in north Wales. NASA might meed to revise its claim that Neptune has the solar system's highest winds, I'm pretty sure our campsite beat them... )

[ngunn]

I've missed the past few days' developments, was on camping trip/SAS survival training in north Wales.

There were no developments because we had no pictures, so your trip was perfectly timed in that respect at least. (Where were you camping? I've often driven past weatherbeaten camp sites in places like Capel Curig and felt sorry for the inhabitants. Next time ring me and you'll have welcoming roof, walls and coal fire.)

[Of counsel]

There is too much physical relief in "crator B" to be, in my estimation, the rim of a relatively small, distant crater. Therefore (and this is a big leap of faith), I think fredk has identified for us the first view of Cape York.... there, I said it. Let me be the first to congratulate fredk. (Alright, you can start shooting at me now.)

[Stu]

There were no developments because we had no pictures, so your trip was perfectly timed in that respect at least. (Where were you camping? I've often driven past weatherbeaten camp sites in places like Capel Curig and felt sorry for the inhabitants. Next time ring me and you'll have welcoming roof, walls and coal fire.)

I did time it well then! We were just outside Rhoss on Sea, up a hill...somewhere... and it was a v short notice thing, so didn't want to ask for bed and board, but next time, for sure.

[Stu]

I think fredk has identified for us the first view of Cape York....

Hmmm... not at all sure... I think we've established that Cape York is below the local horizon, ineide the rim of Endeavour. But interesting, whatever it is.

[fredk]

I forgot to add that my horizon view above had 3x vertical stretch, so in reality the mystery horizon feature is quite a bit more subtle than it looks there.

Whatever it is, it's more or less in the direction we're headed, so it'll be a nice reference point in the drive-direction pancams in the weeks to come. Kind of a silhouetted "beacon", so to speak...

[algorimancer]

Hmmm... not at all sure... .

Crater rims (in my limited experience) have generally resembled a low, flat-topped, hill. This feature seems to have a couple of distinct "peaks". It's in the right direction (bearing in mind that there's a fair bit of angular drift in the IMU, something like a degree if I'm recalling correctly), and the intervening topography is not well mapped, so Occam's Razor is hinting at Cape York. That being said, I don't see any hint of the foreground line which would be indicative of something more distant poking above it, so let's call it a candidate.

Occam's Razor. There's a neat potential name for a landscape feature

[ElkGroveDan]

It's in the right direction (bearing in mind that there's a fair bit of angular drift in the IMU, something like a degree if I'm recalling correctly), and the intervening topography is not well mapped

Occam is rolling over in his grave. He never designed his razor to be used with caveats.

[algorimancer]

Occam is rolling over in his grave.

I did say it was "hinting" Let's call it a 52% probability; if I had more time on my hands I'd firm that up, but we'll know either way in a month or two.

[fredk]

Some craters do have a "peaked" appearance from afar, such as Santa Maria on our approach.

I checked one more measurement: Stu's "Cape approach crater" (my main B candidate) should appear about 0.5 degrees wide on 2603. That matches with the horizon feature.

[Stu]

As much as I'd like it to be CY - always nice to see your destination on the far horizon - naaah, not buying it. The peaks only stand out in the vertically stretched image, and we've already seen that 1) we're in a local dip, and 2) CY is almost inside Endeavour, on an inward-facing slope, so I just can't see how we can see anything of CY yet. As others have said, I don't think we'll see CY until we're almost falling over it.

[jamescanvin]

I did some checking and my money is on Fredk. That crater is the best match for what we can see at the moment.

[marswiggle]

A little 'anaglysis' to support other methods, showing the last kilometer or so of Oppy's hypothetical remaining path to CY in 1/4 of the full size, with annotations at key points (lines approximate). It's likely that the southward rising high ground crossing the middle of the frame, also visible in pancam views, is obstructing our view to CY itself, although I would guess that there's only an (Occam's) razor-thin line separating our views of CY's crest and the bulge crest, given that the highest point of CY also seems to be the absolutely highest point in this anaglyph. It's perhaps noticeable that CY's highest point is not where you might expect it to be, i.e. the sharp-looking crests with shadows, but somewhat to the south of them (more clearly seen in a higher-res anaglyph). The 'Approach Crater' has a raised rim and is located only some hundreds of meters short of the bulge crest, so that's most probably what we see in the horizon.

Attached thumbnail(s)

 

[Stu]

Rough go at a mosaic of most recent pics...

http://twitpic.com/52u9z4/full