Thanks fredk. My track record of matching low-relief terrains is very poor. However, that match looked to-good-to-be-true.

Jack

Here's the navcam mosaic.

Shattered/cracked rocks at Oppy's 'feet'...

Click to view attachment

Now that the "Wedge" (aka several other names) is clearly within reach, I find myself wondering: how would we distinguish between a small fluvial gully (unlikely) and a fracture-based gully (likely), much less a fluvial feature which happened to flow through an existing fracture? The obvious distinguishing characteristics of a fluvial feature on at this scale, the flow-shaped sand and silt on the floor, would have long ago been wind-eroded and partially buried by dust and dunes over time, and water-smoothing of rocks in unlikely if water flowed only briefly. It seems to me that the null hypothesis would be to assume it is fracture-based, and the only way to rule it out would be if a cross-section of the floor sediment happened to be exposed, perhaps by a small crater or intersecting fracture, and clearly fluvial-derived layering were visible. At this point, Occam's Razor has me firmly convinced that it's a fracture feature, but it would be interesting to learn otherwise.

i wouldn't be surprised if the "wedge" turns out not to be a gully or depression at all...

John

If there is a continuation of a shallow depression up into the hills (possible in the HIRISE image), that might be a piece of evidence suggesting a filled-in gully.

I think that, to be realistic about geomorphological processes in an area like this, with plenty of evidence of erosion since Noachian times (see Golombek's recent paper on crater ages in Meridiani, saying basically all Hesperian craters are completely eroded away, Erebus etc. are Noachian), a Noachian gully on this scale would not have survived. Filling it with debris and exhuming it recently is too ad hoc. A fracture induced by the impact forming the crater Antares just to the north, or a gouge created by its ejecta, is much more likely.

Phil

It seems likely to me that this notch is a relatively recent feature created by aeolian erosion along a zone of weakness such as a fracture. By recent, I mean tens of thousands of years to perhaps a few million years old at the most. I hope we'll get a close enough look at it to see if fracturing is involved.

At the very northern tip of Cape York is an almost insignificant geomorphic feature that I have been calling the mini-Notch. It looks like a minor, wind-eroded gully that is oriented in roughly the same NE/SW direction as the main notch or wedge. This suggests the possibility of an underlying structural "grain" that could be controlling the orientation of zones or planes of weakness in the bedrock. We already know that the rock is fractured because the calcite veins appear to be fracture fillings. However, I haven't noticed many of the calcite veins oriented in the same direction as the notch.

We seem to be heading in the general direction of this mini-notch. It's only about 120 feet to the ENE, so perhaps Oppy will slow down for a few pics if she passes by.
Click to view attachment

I've been eyeing that mininotch too, Rocker...

Great news in the latest update:
That's just what we need for:

There seems to be an inner and an outer bench at this part of Cape York. I'd expect them to continue northward to look at the edge of the outer one before heading SE towards both notches.

Couple of MI frames came back... tried my best to make something out of them...

Click to view attachment

I don't think it is either.

If you look at the "bath tub ring" around Cape York, from HiRISE you get the impression that there is a small vertical "step" like feature surrounding the Cape, but images from Opportunity show no such thing. I think the Gully is probably just a"slice" out of the white outcrop with no vertical relief at all. probably

Well that peed on our chips, didn't it?

Don't give up hope yet, Stu! I think there is some relief. Remember when we first made landfall on CY almost a year ago, there was a bit of a step up - check out the vertical stretch in this post.

We had a good look at Whim Creek (the wedge/notch) on 2917. The sun was low in the west and it really looks to me like the far side of Whim Creek is sloped towards the west since it's very bright (arrowed feature):
Click to view attachment
So I'm betting for some relief, but nothing too dramatic - this is Meridiani, after all!

There is undoubtedly some relief at the notch, but I would have to agree that there is less relief than we were expecting when Cape York was first announced as Opportunity's next goal after Victoria.

Of course, none of us were surprised by Cape York's lack of relief, either.

Well, I think that the "dagger" will turn out to be a very old filled slump crack in the rim. If the Endeavor crater was formed amidst the process that was depositing the Meridiani sediment, the details of the "dagger" fill could be instructive, since they would be kind of a snapshot of the time. (Since the "dagger" extends into the Meridiani sediment a ways, it is younger than the rim, but probably older than the end of the Merdidiani deposition.)

Well phhhhtttt! on all of you. I'll go out on a limb and depart from the nose-in-the-air, poo-poo chorus. I think it's an aqueous erosional feature (likely buried and exhumed several times) that was created as water drained from Meridiani over and around Cape York into Endeavor Crater.

Go ahead and laugh. They laughed when I said I wanted to be a comedian, but no one's laughing now.

Right on, Dan. We'll see what it is (maybe) when we get there.

Anyone who was expecting gypsum veins prior to arrival, please weigh in on this issue.

It's a vent emitting psychotropic gases, as at Delphi. When we get there we'll learn what we don't know.

OK, if you want to know what I really think it is, parsimony dictates that it's an outlet for the Abyss in the Columbia Hills near our resting friend, Spirit. Fluids spiral down into the Abyss, through the Martian core, and empty out here. The fact that the flow pattern from the notch appears to be horizontal rather than downhill into Endeavour is easily explained by ngunn's psychotropic gases.

So is there a name to the rule that the signal-to-noise on this forum drops and silliness goes up whenever new pics are scarce?

No relief in sight, you say? - Nothing that a bit of a stretch can't solve is my answer...

Fred, the rule is unwritten but can be summarized by the following:

Patience, all, patience...

> So is there a name to the rule that the signal-to-noise on this forum drops and silliness goes up whenever new pics are scarce?

Exploratorium Withdrawal Physcosis:
A psychiatric disorder that is marked by delusions, hallucinations, incoherence, distorted perceptions of reality and posting silly things when the individual cannot see or manipulate images from a distant planet.

If we don't get a fix soon it will be "patients, all patients"

Phil

In keeping with the current discussion...

EGD,
I'll see your "phhhhtttt!" and raise you a "BWHAHAHAHA!"

It is the scar made by Martians doing a wheelie in their ground transport unicycles, after laughing at the primitive Earth contraptions showing up...

These are not the 'droids you are looking for.

Move along, move along....

Whatever the reason for the inspired humor around here, I'm all for it.

I'll put my money on "nest dug by High Speed Turtle to lay its eggs".

Ok, back to business. The exploratorium may be somehow stuck but the images pipeline to the mission's website is working.
Here's a 360deg. navcam mosaic from our current site.
Click to view attachment

And looking to the imaging sequences planned to thisol, it seems that some RAT activities are scheduled.

02995::p1110::02::2::0::0::2::0::4::front_haz_mi_1024x1024x1bpp_pri56
02995::p1121::03::2::0::2::0::0::4::fhaz_idd_apxs_doc_512x512x1bpp_pri56
02995::p1140::02::2::2::0::0::0::4::front_hazcam_rat_doc_sbfrm_4bpp_crit
02995::p1141::00::2::0::2::0::0::4::front_haz_idd_rat_doc_512x512x1_bpp_high
02995::p1154::01::2::0::0::2::0::4::front_hazcam_idd_unstow_doc
02995::p2142::12::1::1::0::0::1::3::pancam_RAT_verification_R1
02995::p2596::29::2::2::0::0::1::5::pancam_Grasberg1_R12

... and Tesheiner's great panorama in circular form with a close-up. The dark lines that looked like topography along the contact in HiRISE images are not topography at all... what does that mean for Whim Creek?

Phil

Click to view attachment

Click to view attachment

RAT brush of 'Grasberg1' from 2995

James - nothing's shown up from 2995 on either of the jpeg sites, and that image looks much higher resolution than the thumbnails - what's up?

A contrast stretch on James's nice new image - those veins look interesting.

Phil

Click to view attachment

Fred: they're just from the JPL site

(I earlier posted something about them being stamps; turns out I was wrong, go figure.)

Yes, they are now, but as I said those pics weren't at either of the two sites (exploratorium or jpl) at the time. (I did do forced reloads.)

Maybe it's the particular jpl server - I use marsrovers.jpl.nasa.gov, but your link is to marsrover.nasa.gov. Maybe one is updated a couple of hours before the other?...

Could be? I think I've seen evidence of that before, but I'm not sure. I just hope Exploratorium comes back soon.

I was wondering how long it would take for someone to notice that I posted that before JPL/Exploratorium had them!

They are from the 'Mars Images' iOS app (Android version also available I believe) released in January by Mark Powell from JPL.

http://itunes.apple.com/us/app/mars-images/id492852224?mt=8
http://www.powellware.com/Mars_Images/Mars_Images_Home.html

It has been updating as normal (un-stretched images as a bonus!). The issue with it is that it appears the only way to get the raw images out of the app is to email them to yourself one by one, so fine for a one off but not for larger mosaics.

James

Thanks for letting us know about that, James. So does that give you all of the pics that come down each day, or just a selection? Are they full resolution?

You say they're unstretched - they're still 8-bit jpegs? Wouldn't that give you lots of saturated (0 or 255 value) regions? I have to wonder about calibration. I thought that stretching was what made it impossible to recover the calibration in the jpegs. But you'd also need exposure info, and these jpegs presumably have an unknown overall scale factor applied. Presumably the team still doesn't want public access to calibrated images before the 90 day period is up.

I need to decide if it's worth trying to install a smartphone OS emulator on my windows machine! Perhaps these images are sitting on an ftp or http server somewhere and so they could be retrieved without this software? Or perhaps it uses some different protocol?

It's worth sending an email to Mark asking him some of these questions. Worst is he doesn't answer!

All of them at full resolution except things like tau and calibration. (maybe others like sky images, I haven't checked in detail)



Yes, 8bit jpgs, they do not have lots of saturated regons, the full 12bit range is clearly mapped onto the 8bits range rather than just a portion of it with the stretched images, this does mean that some images can be a bit washed out.

I've often worndered about combining the two versions to get back to something closer to the original. But time, and the difficulty of getting images out of the app combined with a thought that this might be pushing things a bit far which would just result in getting this feed turned off (or at least switched to the same images as on the web) has stopped me.



Yes if we did want to use them properly then finding an easy way of getting the images downloaded would be needed. It is very slow emailing them manually one by one. You would have to talk with Mark about this and also about any issues if we started using them to reconstruct higher quality images.

James

Most MER images, especially most or all ECAM ones, have 12 bits encoded to 8 on board, and they come to Earth as compressed 8-bit images. The process uses a look-up table that approximates square-root encoding. There are multiple tables, but one gets the most use (it's a linear/square-root hybrid that uses all 8 bits--the idea being that it is a noise-limited encoding). In calibration, there is an inverse-LUT process to restore 12-bit range. Some tools use the 8-bit version, some the 12-bit one. I do not remember what Mark P does -- but it seems likely if 8-bit images have the full dynamic range, they still live in LUT-land.

PS, for those who want more detail on the LUTs, see Bell et al. 2006, doi:10.1029/2005JE002444, Appendix A.

Thanks for that reference - I don't know how I'd missed that.

Pretty low-sun-angle shots starting to come down now:
http://qt.exploratorium.edu/mars/opportuni...6M1.JPG?sol2985

Tweeted by Paolo Bellutta‏

@bellutta
Not only did I get to grind my 4th hole on Mars today, but was stunned to see that the power predict for Sol 3000 was almost 600W!!!!

Yes folks, that's 600W

Delighted...Go Oppy, windward....
Does this signal the drive...?

For sure we will stay put for one more Sol to complete the IDD work (post grind MIs, APXS). Possibly Tuesday or Friday next week will be a drive planning cycle.

Paolo

Thanks for the update, Paolo - should that be post brush?

No Fred, the chatter on Twitter is that there is going to be a real RAT grind!

Should have just happened, images soon I hope.

Yes, we will be doing a shallow (1.5mm) grind on Sol 2998 and therefore there will be the usual post grind MIs and APXS. The brush happened on Sol 2995.

Paolo

Look what you did, Paolo...!

Click to view attachment

Loving this.

All-time low Taus, combined with massive cleaning events... it's beautiful.

-m