There IS more dust over meridiani:

Taken from http://www.arksky.org/alpo/index.php
October 30th:

Obviously MOC WA will be catching this lot, but it's fortuitously also Hubble time, Jim Bell et.al. had one and have another session, so they should have caught it in all it's glory as well - a nice flow of data if they get it right from Hubble, to MOC WA, to MERB

Doug

It may not be curtains. This is a plucky little robot.

(putting on my best William Conrad voice) Will our intrepid explorers, Rocky and Bullwinkle succumb to the dust monster? Tune in next time...

I agree with Doug, the FHazcam image may be misleading. Argh! Only _that_ image online for Sol 627, and no others. But look at the second FHazcam image posted by Doug, the reflection of the bright sky off the polished aluminum piece is _very_telling of sky conditions.

We'll know more when the other Sol 627 images are up.

--Bill

When I go to the JPL RAW site all I see are broken links for the latest sol 627 images.

Grrr! Broken links, exploritorium not updating, what's happenning to Oppy????


Nick

Weird, they dont show up for me in any browser I try.

You have to insert "%23%23" in the filename where it says "##"

When I talked to Steve Squyres a few months back he said that dust accumulation on the panels after a storm was not a consern. Lets worry about the storm itself for now.

James

Heck, let's sit back and watch the storm.

Pass the popcorn, please...

--Bill

On earth, dust storms can definitely reduce available sunlight, but they are a real pain when it rains at the same time. Then it's time for a car wash. I'm a bit worried about accumulated dust, but also hopeful some dust will blow off the panels. It probably doesn't make a lot of sense comparing this dust storm to those on earth, though.

Both the original and the 'unstretched' hazcams posted looked pretty dusty to me. But I'm with Bill on this. Pass the popcorn and the Pancams, please.

new pictures...

http://nasa.exploratorium.edu/mars/opportu...cam/2005-10-31/

Newst pictures are 3 days old...

But somehow Exploratorium has gone crazy updating...
Looks like all Spirit images have been reloaded on the 31'st... That's gonna kill MMB

This Rear Hazcam is additional one from sol 627:

http://marsrovers.jpl.nasa.gov/gallery/all...23P1315L0M1.JPG

Looks more dusty too in comparison to one sol older pics.
It's the same time like this one: http://www.unmannedspaceflight.com/index.p...indpost&p=24937

It's unbelievable how we have to scrape up the pictures in these days

But the shadow of the rover still looks sharp and crispy!
Most of what we're seeing is dust on the camera, isn't it?

Did it ever show if the dust that accumulated on the Viking landers ever blew off?

Was a dust devil ever seen by them, even if its true nature was only realized years later? I can't believe that no dust devils ever passed by them even once during their operating lives.

This didn't quite show what I'd hoped it would, but here it is for your FWIW file...

Here is a montage of four Forward Hazcam images from Sols 627, 626, 624 and 616 that semi-shows a build-up of dust in the atmosphere, but not conclusively.

--Bill

Think so, but it's really windy for a few days.

The latest hazcam pictures show the shadow as being sharp - as I would expect.
BUT the shadowed zone is lighter indicating that there is more "ambient" light.

Think of the sky here on earth and compare the shadows on a cloudless day:
1) in a smoggy city (say LA)
2) in mountains.
Both have crisp edges but the contrast in the mountains is much higher.

The latest rear hazcam images definately show a reduced shadow contrast.

Nick

I imaging the stretching of the "raws" wrecks havoc on our ability to determine how much the brightness of the seen is effected.

Dust devils were detected by other instruments. But because the Viking cameras were slow, line scanning systems, they wouldn't have shown up in images except as perhaps a funny looking line or two. This is why Pathfinder and the MERs see them - they have framing cameras.

Did Pathfinder actually see one ? Don't remember.

I don't think it saw one but they felt at least one with their wind and pressure sensors.

True but there are a couple of things to note that can give us something to work on.
Tau=5. There will be no clear shadows at all, at noon the diffuse illumination will be about 2 orders of magnitude more intense than direct beam illumination and it's even more extreme when the solar elevation is low.
Tau=2, There will be faint shadows, diffuse lighting at midday is about 5x the intensity of the direct beam, and once again that rises significantly further from noon.
Tau=1, Clear shadows are visible but shaded areas are well illuminated. Diffuse light is about 20% higher than direct at noon. Overall daily diffuse insolation is about 80% more than direct beam.
Tau=0.5, Crisp shadows and shaded areas are noticably dark. Direct beam is ~70% more than diffuse light at noon. Total daily beam insolation is abotu 20% more than direct beam.
Tau=0.1, Extremely well defined shadows. Beam lighting is ~10x the intensity of diffuse at noon.

Things get a bit fuzzy very early\late in the day when tau is above ~0.2 as direct beam falls off rapidly at low sun angles while diffuse light falls off pretty slowly.

Here is another evaluation of the sky brightness. Using two "similar" Rear Hazcam images, I used the bottom of the solar panel as a greycard to measure the incident light from the ground onto the panel. Selecting two 75x75 pixel apertures on the right and left sides of the panel in each image and averaging the value in each aperture, I adjusted the brightness of the two images so that the value of each aperture was the same in both images. This way, I ensured that the "greycards" had the same value and this allowed me to evaluate the relative intensities of the shadowed areas in the foreground. This is meatball photometry since it disregards a lot of variables, but I think it suggests that the shadows are brighter on Sol 627.

FWIW^2.

--Bill

The Meridiani Planum does not have dark strikes on the land as the product of dust devil. Hence, that zone does not occurs dust devils unless in the Gusev's basin has lots of dark strikes around the Columbia and Cook Hills. Thus, that zone is considered as North West (aprox 350 degree) to South East (80 degree) constant wind. You can see the formation of ripples: the west side of ripple, the surface is somewhat rough with minor canals toward the ripple and the east side, you will notice as a plain and smooth side due to the dust or sand accumulation by the wind.

Rodolfo

Some info from the CNN website:

"Lemmon said that data returned to Earth Friday by Opportunity showed elevated dust levels at Meridiani Planum, which were measured at an optical depth of about 1.4. The largest dust storm experienced by the rover occurred in June and rated an optical depth of about 2, he added."

(...)

"Lemmon suspects that Opportunity experienced one of the "fingers" of the storm photographed by Sherrod, adding that later atmospheric measurements were lower than the 1.4 optical depth seen earlier, but not quite at the moderate 0.5."

So it's not looking too bad at the moment. Go Oppy

Nothing on 629 at all, and just monitoring on the other two - perhaps something of a hunker-down-mode?

Doug

Yes, it will only be looking a narrow angle from west (288 degree) to south (108 degree) ... I suppose that the summer time the sun would be passing to sunset on that angle.

Or perhaps, that angle is the proposed route so the team wants to focus closer the terrain toward the Mogollon rims. It might means that the rover will advance too. I think that the only change has come out from Pancam Tracking Databaes is that now it does not show any engineering commands that previously had appeared. Still not sure but I noticed and it might be too early to jump conclusions.

Rodolfo

It spotted a few...I have some images somewhere...I will have to dig...

No - when the rover drives, you ALWAYS gets Hazcam imagery, Penultimate, Ultimate, and if it's a long drive, 'Stumble' as well

Doug

The Pathfinder did indeed image several dust devils. See this paper for a description.

The Pathfinder atmospheric station also recorded the wind and pressure changes associated with a dust devil passing over the lander. See Pathfinder Dust Devil meteorology.

That's not the way I read the PDT (Pancam Data Tracking, I think it's time to abbreviate this) I beleve that it reads

navcam_7x1_az_288_3_bpp

7 navcam frames centred at az 288 degrees

navcam_3x1_az_108_1_bpp

3 navcam frames centred at az 108 degrees

Note that 288 - 108 = 180. i.e the centres are in opposite directions. Also note that 10 navcam frames generally make a 360 degree pan.

So these two lines should be read together as simply "A 360 degree navcam pan".

James

Looking at the pancam site the last few days, im sure data was received the next sol, which would be sol 630.

I worked with some of those Patfinder images once. This is what I got by merging color data with some dust devil imagery. The rest of the stuff I did was lost in a computer crash, and I haven't had the will to go redo it, given the quality of the MER images.



Also, here are a few other images (I did NOT process these, but, as they are scraps from the crash as well, I have no idea where they came from.)

Ted have you ever found the equiv of Pathfinder RAD data. It's listed on the PDS - but you have to be a Nasa funded researcher to grab a copy, I've only been able to grab something that's basically, not too different to the plain EFF's

I think the Pancam Tracking site might be a bit out of date, perhaps they're 'doing' something to it.

Doug

From the Mission Status at the NASA/JPL site:



My feeling is that the dust devils, "convective wind events" or whatever occur at Meridiani just as at Gusev. Whereas Gusev is dustier, we are able to see the dust devils and the tracks they leave but Meridiani has a cleaner surface covered with the blueberry pavement/armor and the DDs are less visible.

--Bill

jamescanvin: Good and smart hint! I didn't know that to make a 360 panoramic pictures needs 10 Navcam.

Rodolfo

Oppy's dusty weekend
http://marsrovers.jpl.nasa.gov/mission/sta...tml#opportunity

always a new twist for the programmers:

"...The morning after a deep sleep, the rover wakes up when solar panels start putting out a prescribed level of energy. However, a dust storm in the Meridiani region reduced sunshine enough on the morning of sol 628 that Opportunity did not wake from deep sleep early enough for the first scheduled activities of that sol. The rover's onboard software properly put Opportunity into self-protective automode for the day,..."

So the programmers now have to program in anticipation of the expected solar panel output as diminished by expected tau for the coming day.

Has anybody seen a new picture of the dust storm? Arkansas Sky Observatory seems to be too eastward (or too westward? ) now. The last pictures there are showing the storm went more in a southward direction.

Now that's a concept! Miss the alarm - so stay in bed for the day. I could work with that

FOR RELEASE: 9;00 am (EST) November 3, 2005

PHOTO NO.: STScI-PRC05-34a

MARS KICKS UP THE DUST AS IT MAKES CLOSEST APPROACH TO EARTH

NASA's Hubble Space Telescope snapped this picture of Mars on October
28, within a day of its closest approach to Earth on the night of
October 29. The large regional dust storm appears as the brighter,
redder cloudy region in the middle of the planet's disk. This storm,
which measures 930 miles (1500 km) has been churning in the planet's
equatorial regions for several weeks now, and it is likely responsible
for the reddish, dusty haze and other dust clouds seen across this
hemisphere of the planet. Hubble's Advanced Camera for Surveys High
Resolution Imager took this image when the red planet was 43 million
miles (69 million km) from Earth. Mars won't be this close again to
Earth until 2018. Mars is now in its warmest months, closest to the Sun
in its orbit, resulting in a smaller than normal south polar ice cap
which has largely sublimated with the approaching summer.

Credit: NASA, ESA, The Hubble Heritage Team (STScI/AURA),
J. Bell (Cornell University), and M. Wolff (Space Science
Institute)

For the full story, please visit:

http://hubblesite.org/news/2005/34

http://heritage.stsci.edu/2005/34

For additional information, please contact Jim Bell, Cornell
University, 402 Space Sciences Building, Ithaca, NY 14853,
(phone) 607-255-5911, (e-mail) jfb8@cornell.edu, or

Mike Wolff, Space Science Institute, 4750 Walnut St., #205,
Boulder, CO 80301, (phone) 262-790-1356, (e-mail)
wolff@spacescience.org, or

Keith Noll, Hubble Heritage Team, Space Telescope Science
Institute,3700 San Martin Drive, Baltimore, Md. 21218, (phone)
410-338-1828, (fax) 410-338-4579, (e-mail) noll@stsci.edu.

The Space Telescope Science Institute (STScI) is operated by
the Association of Universities for Research in Astronomy, Inc.
(AURA), for NASA, under contract with the Goddard Space Flight
Center, Greenbelt, Md. The Hubble Space Telescope is a project
of international cooperation between NASA and the European
Space Agency (ESA).

Woow, that's another highlight from Hubble! Mars in action.

And last but not least, it give us the chance to look closer at Oppy's position in comparison to the storm from 10.28.

Tried to overlay a map from USGS Mars General Image Viewer:

http://www.greuti.ch/oppy/oppy_dstormkarte.gif

Oppy's position is directly next to the "M" from the "MER". A bit more to the right than the arrow in the official image today.

Very nice! Thanks Tman.

There does not appear to have been a dust deposition problem with the recent dust storm; it seems to have been a cleaning event.

Sundial L456 images from Sol 594 and Sol 644.

--Bill

This would be good news - seems the answer is blowin in the wind after all.

Though am I the only one that thinks "cleaning event" sounds like some horrible euphemism?

" Heinamackafrau?"

I will gladly trade eine kleine spreckles on the hazcam for clean solar panels.

What do you think that white stain on the left of the dial is?

I was looking at that marking on the left side of the sundial post and it's irregular border and the only thing that came to mind was "spark discharge".... I'm wondering if it's ultrafine dust adhering in a pattern involving a corona discharge or something. Wild-ass-guess speculation, but that thing's weird!

I'd love to see current pics of that aluminum pole with a donut on top.. I've forgotten which antenna that is... Earlier in the missions, there were two elliptical patches of dust adhering to it in a distinctive pattern that I suspected might be due to electrostatic attraction or adhesion of dust involving strong electromagnetic fields at that point. I'd have to extensively dig for a pic that shows it well.

The bright ...splotch is a persistant feature that showed up sometime between the last sundial images taken on sol 620 and the first ones taken on sol 621. That sol was less than a week before the large dust storm that came so close to Opportunity, and during the period described by Dr. Mark Lemmon in the space.com story quoted by Rakhir in post #33 of this thread:

"We started seeing more and more dusting on the solar panels," he added. "And we have indirect evidence that these storms are windy. We've seen material blown out of the rover tracks over the last two weeks."

The appearance of this marking (which, based on the conditions at the time, I'd guess to be a windblown dust deposit) might have been the moment of peak winds, and probably "points" in the direction from which the wind came.

I have no idea what that white "splat" is. I noticed it as I processed the image, but decided to let comments here go where they may. "White" colors imply sulfate salts and the splattered nature of the mark and it's timing implies a wind-blown collision, so I'll let it go at that. I'll imagine (or not _imagine_) that it is bacterial or frost...

What is the sundial post made of? I'm thinking anodized aluminum, but I can't find a reference on it.

--Bill