a nearly black moon at extremely low phase angle will be a very low surface brightness very narrow crescent and not visible.

Sol 795 : April 18 at 17:54 , The bright spot is not of phobos but any other. See the following picture which is view of Phobos from Mars: Not pointing close to the Sun but on the other side: Click to view attachment

The bright spot might be of Mercury or Venus. See the following picture shown Sun by Mars at that time: Click to view attachment

Rodolfo

Rodolfo, unfortunately there is no hope to see those object on this exposure, unless you have a coronograph...

If you want to see planets/Phobos, you need to have the sun below horizon, like in this Family Portrait.

In fact, if you look to other pictures taken with different filters, the bright spot are elsewere... conclusion: they are sensor artifacts (hot pixels) or cosmic rays!

Oppy drove again on sol 799 (site/drive id 6912 -> 69FJ); that's what I get from the tracking web.


But meanwhile, the exploratorium seems to be down; no new pics since the 21th.

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The sol 799 images are available at:

http://marsrovers.jpl.nasa.gov/gallery/all/opportunity.html

tty

Oh well, looks like Opportunity will need to have a 1200 meter drive tosol for my Sol 800 prediction to work out. Suddenly it's looking pretty unlikely. Good luck to those with predictions around 880.

Here is that annotated image I used few days ago to compare orbital vs. ground features, now with what I believe is the rover position after sol 799 move.

Click to view attachment (287k)

There are plenty of places to go on the current outcrop, but based on the "drive-direction" pancams (headed at ~110º) this is where I think Oppy will be headed on sol 800. That would make an aprox. 25-30m drive eastwards.

Click to view attachment (145k)
(Sol 799 navcam mosaic)

Happy sol 800!

Good move. That 110* drive direction will head Oppy back to the cyan hypothetical route line shown on your Route Map. I'm thinking that your proposed route will be close to the one that is followed.

--Bill

That makes sense as a destination. Do they have enough control to make it zig-zag a bit on the way there to avoid the dunes, as seems possible here... or is a straight drive the most expeditious way to go?

Not that I want the drivers to slow down for a closer look, but what do you all think has caused the little ridges we're seeing here in the salt flats. Is that a local feature, or sould we expect increasing unevenness as we continue to head South?

If I did my math correctly, halfway to the proposed route.




I have the feeling (quite subjective, isn't it?) they will choose a straight path whenever the most of the wheels are on hard rock, which is the case here.

Happy sol 800!

Oppy Sol 800 happy!

Here is the view Southeast on Opportunity Sol 799:

It looks like they don't hesitate to barrel right over drifts of reasonable size. I guess the trick is software that prevents the rover's digging in if forward motion is stopped by excess slippage. I'm still a little surprised when images of tracks indicate an apparently carefree trek over several drift crests. And luckily the drifts are a lot less imposing than one might have imagined. I hope it stays that way.

There is a bit strange feature on this dune :



In your opinion, what sort of phenomena has mad this?

The wind. Sorry, i don't think there is anything unusual or strange in the image you have posted.

I think the stripes on one side of the drifts are the traces of previous downwind surfaces, with different types of dust etc. The would mean that roundish feature in the image is a hollow that formed at some stage and was then filled - perhaps a gully from some shift in the rocks, or a slump of some sort, or a minor impact. It must have remove existing material from the drift to give that distinctive break in the stripe rounghly halfway up, which then refilled "rapidly" with a different era of drift material.

You've been on Mars too long.

I think he's talking about the circular dark spot, similar to the "oil stains" we noticed way back. I don't think there was any resolution to that discussion, other than they may be tied to the tiny craters...

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This one seems to have a bright rim to the upper left side, so it might simply be another of the microcraters, just seen from a different angle and/or perhaps less freshly made.

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Hmm... I assumed that the sand surface was flat, and we were looking at a coloration effect... but I guess there could be a dimple there.

waste of time discussing this really - it's pretty obvious some Martian took a leak here

Most probable aeolian, as paxdan assumes

Nico

My best guess is one of those microcraters having been filled up again with 'fresh' dust.

Seems very similar to the dust-clearing effects of the retro rockets when Oppy landed... just smaller

Have we crossed the high point yet?, if not, it cannot be far off

I have two fears to drive much over outcrop. The problem is that outcrop has many cracks and the small Oppy's wheel can be stuck inside. The other side, the vibration of wheels over the hard outcrop would make any problems with wheels actuators or motors or any other parts of rover.

I think that the one of wheels, right front of Spirit was damaged after this wheels has jumped over a small stone. The vibration might have shaked much on it and after a few cms after a stone, the motor of this wheel stopped roving.

Rodolfo

This xeyed shot suggests the surface mottling across the area is constant and that there are no surface dip or ridges which would be suggestive of a filled micro crater impact.

Click to view attachment

The left BW image does suggest the appearance of surface tear running across the dark spot from about 11 to 4.

I suggest NASA found it an interesting enough surface to stop and do a complete PamCam filter sequence. These dark spots have been seen before but, to my memory, never on an adjacent dune face to Oppy's track.

More and more interesting. How about this: perhaps a micrometeor self-destructed in an air burst within centimeters of the surface? Seems pretty unlikely. How about a dust devil touching down on the spot?

Not shure about last sentence, anyway I thing is worth to make deeper analysis also through wheel digging.
(Did someone mentioned lighting burn as potential mechanism?)

The initial trace of an abrupted mini dust-devil was on my mind too.

Nico

Speaking about "traces"... no trace of sol 800 images for the time being.

It was a driving sol and per the data on the tracking web it was executed and some 30 new pics were downlinked (sometime in the morning - European time). Meanwhile, neither the exploratorium nor the MER webpage have those fresh images.

Still waiting...

Yeah, it's a bummer that Exploratorium is down - they only seem to update the JPL raw images once a day or so. Still, it's better than nothing.

Oppy had the opportunity to see closer on dark spot when she got out of Purgatory Sand by few meters. That was a long time ago, around May 2005.

Rodolfo

Not in this thread I think, but the possibility have been mentioned in earlier discussions.
And I think I followed a link to a page about possible Martian lightning from a post here quite long ago.
If lighting actually is the cause of that circle some trenching with the wheels might unearth (or un-Mars) some fulgurites, glass 'tubes' or nodules.

OK we may not have pictures yet but...

If my understanding of the data tracking site is correct, then the drive to 69KE on sol 800 was 30.8m on a bearing of 112 degrees.

James

I just hate when this happens...Exploratorium is down for 5 days now and MER main site is updating rarely on time...
Does anybody knows what happened to Exploratorium now???

Well, we have at least the tracking web pancam thumbnails. Better then nothing.
I did a not-so-quick&dirty manual stitch of those little 200x200 images and this is the result.

Click to view attachment

Same in polar projection.

Click to view attachment

This outcrop to the SE seems to be that one which was "hidden" behind the dunes (Shaka?) but the resolution of these images is not enough (for me) to make any driving estimate.

Sol 800 pictures are now avaiable:
Opportunity Raw Images

Now it seems Victoria's northern vicinity or rim is completely visible.

Looks like quite a steep drop down to the lower plain after Oppy clears these dunes...

Anaglyph

It seems to be working again now...

And includes Sol 801 images

James

Some new pics (sol 802) are available at the exploratorium.

http://nasa.exploratorium.edu/mars/opportu...cam/2006-04-27/

I would expect the remaining ones in the next update cicle.

And this is where I would locate the new site in a sol 801 navcam mosaic. Some 15m (parallax) from the last position.
Click to view attachment

Hey, what happened to the bright spot at the top of Victoria?
visible yestersol
http://qt.exploratorium.edu/mars/opportuni...NVP2396R2M1.JPG
but not tosol
http://qt.exploratorium.edu/mars/opportuni...Q4P2398L2M1.JPG

It is barely visible.
Pixel coordinates: (320, 111)

lots of gravels between large dunes. Why gravels is not everywhere, but only somewhere.

Yes, it is odd. Do I point a finger at more recent impacts around Victoria as a potential source of these gravels? Could it be ejecta that has splattered over the underlying lighter rock, landing thicker in some areas than others, before the dunes redeveloped here after whatever blasted them away?

(What I'd give for some dating equipment and half-an-hour's careful shovel-&-trowel work around here!)

Andy

This is sol 802 pancam mosaic (56ºfov, centered at 160º), at 3/4 size. It looks we have reached a local high point.

Click to view attachment (368k)

Rotating beacon?

More likely sun angle change.

In the satellite image of this area we are using for the travel map, there are areas where the dune fields look much darker than the areas Opportunity has been driving over. I'd always taken those areas to have taller more treacherous dunes, but it appears that it is just that these areas have dark gravel (as you call it) covering the exposed salt between dunes. That might change (ease) the requirements for our zigzagging path.

Did anyone mention that Exploratorium is back up? Hooray!

Sweet!!! I'd be surprised if JB doesn't admit that the low rise in the far background is Victoria. What else could it be? There is another rise on the left edge of the horizon, so I guess there's always a chance we're just seeing another large dunefield at a distance that can't resolve the individual dunes... but my money is on Victoria.

Some fancy footwork by Oppy in the past drive! Nice!

That was yesterday

Nico