As your rough map is rather disorted it would be interesting to see a south polar view, probably with a grid.
For sure that is only a approximate but a nice overview showing locations of major features

In the last hours, Dawn turned off it's engines and distance/speed are quite stable; this could means he reached a circular orbit but, looking to the plots below, actual speed/energy are below such a level, suggesting that probe is near the apoapsis of an elongated orbit:
Click to view attachment
Indeed, current orbit should be almost circular (5500x5200 km, e=0,028) with a 161 hours period. Obviously, this is true until next (imminent) engine burn, which should be in direction roughly opposite to orbital motion in order to have a progressive distance reduction, spiraling toward survey orbit...

Note: In all my figures, I am assuming that distance declared in the simulator is measured from Vesta's centre...

"it would be interesting to see a south polar view, probably with a grid."

For the time being I will not do this. Better to leave it to the Dawn team to do a proper one. Think of my map as just a guide to image coverage at the moment. For one thing, the latitude scaling is very uncertain.


Meanwhile Dawn has looped over the north pole, and then the equator over the weekend, and it's now back over the south pole.

Phil

Next Monday on NASA TV:

Goody goody

RE: August 1, Monday 2 p.m. - NASA Science News Conference - Dawn Images of the Vesta Asteroid - JPL (Public, HD and Media Channels)

I think that is 2:00 PM Eastern Time Zone or 18:00 GMT for those unfamiliar with NASA TV's broadcast schedule.

Yes, they're always on eastern time. I sincerely hope for movies of the first orbit (has it even been completed yet)?

Very close to completed, at the least. We're over the south pole again (approximately).

A Vesta rotation movie is more likely that an orbital movie because of the frequent times when no images are taken.

Phil

I agree with Phil -- I think (or at least hope) we'll be seeing one of the "rotation characterizations" in movie format, and I would hope also another nice image release from closer in, or maybe more of their reprojected mosaics.

Although strictly the spacecraft is about to complete the first orbit around Vesta, the mission is still are officially on Approach. Science activities will not start until the first week of August.
In the meantime, back to the lit side of Vesta, the camera continues to do optical navigation. I am sure the media team will soon have new images published.

Goody goody goody

I'm moving the Asimov discussion to its own topic now...

Does full frame mean full lighted view of Vesta, or full frame of the field of view of the camera?

Hi, long-term lurker

Anyway I hadn't seen this discussed so far, I hope we'll get to see for ourselves soon, but this piece from the Beeb sounds interesting.

http://www.bbc.co.uk/news/science-environment-14249515

First complete orbit is now almost accomplished (Dawn hasn't been using engines in the last 5 days).
During orbit, the speed and distance were constant; such a circular orbit is possible only if we assume that "distance from Vesta" declared in the simulator is measured from asteroid's surface (otherwise, speed should be significantly higher). I updated plots, using an average Vesta radius of 266km and assuming that also final survey orbit height will be 2700 km from surface:
Click to view attachment
Meanwhile, look to last spectacular "family portrait" from simulator:
Click to view attachment

I'm still a newb at this, is r on the left hand chart the orbital radius?

Thanks,
-kap

By now Vesta is filling the field of view of the Framing Camera, so you will see very nice image of Vesta even without having to zoom in wildly. Indeed, the FC has a 1024x1024 CCD, so the full frame view would fill most of your screen essentially on any laptop.

It's the distance from Dawn to the center of Vesta. When Dawn is in a circular orbit, it'll be the orbital radius. Part of the point is trying to determine when that happens.

--Greg

New image!

http://dawn.jpl.nasa.gov/multimedia/dawn_v...mage_072311.asp

Hmmm.... Is that a dead spider near the bottom?

I was looking at that. Unusual dark splat on the inside of the crater.

Here it is rotated 180, enlarged 5.5x , sharpened a bit, etc.

If I have been following this correctly, the July 23 view is of the north on the night side, yes?

Iapetus, eat your heart out; we have a new snowman!

Vesta is the rock of a thousand faces, indeed (though this doesn't look like a very 'dark' side like the caption says, IMO).

Remembering my crater dynamics, that would mean that it JUST touched a darker, mafic layer (remember boys and girls, basalt is at the surface (or was at least when it formed, gabbro is below your feet, so not knowing where this stuff was formed, let's just say mafic)

By the way, I am definitely printing that picture for my wall in my office.... Where is the swear jar? ***** **** ***** *****!!!

Indeed, this is a view over the dark north pole and part of the northern hemisphere. And, btw, the surroundings of the snowman craters ARE indeed visibly darker, I promise.

That's one huge groove.

I thought the caption meant dark in the same way there's a colloquial 'dark side' of the moon.
If the north actually is darker than the south (and not just shadow), then I stand corrected!

New Event Time NASA To Unveil Vesta Images At News Conference
Monday Aug 1 at noon EDT (changed from 2:00pm)

Update -- New Event Time NASA To Unveil Vesta Images At News Conference WASHINGTON -- NASA will host a news conference on Monday, Aug. 1, at noon EDT, to discuss the Dawn spacecraft's successful orbit insertion around Vesta on July 15 and unveil the first full-frame images from Dawn's framing camera. The news conference will be held in the Von Karman auditorium at NASA's Jet Propulsion Laboratory (JPL), 4800 Oak Grove Dr., Pasadena, Calif. Journalists also may ask questions from participating NASA locations or join by phone.

To obtain dial-in information, journalists must contact JPL's Media Relations Office at 818-354-5011 by 8 a.m. PDT
on Aug. 1.

NASA Television and the agency's website will broadcast the event. It also will be carried live on Ustream, with a live chat box available, at:


http://www.ustream.tv/nasajpl2

To clarify the 'dark' description... and see the camera facebook page for more of those comments! - Vesta has a large low albedo feature on its equator in one hemisphere, first seen using speckle interferometry by Jack Drummond and colleagues in the 90s, and confirmed by Hubble. It is referred to as Olbers and is used as the zero longitude in the Hubble-derived shape model. This image includes the darker longitudes at low latitudes. It is the low-albedo side.

Phil

EDIT - now the caption suggests it referred to passing over the dark (= unilluminated) side prior to taking this image...

The latest image is interesting. The dark area to the right of and a bit below center is interesting. I get the impression that is is at least partially caused by topography. But there is another dark area left of center and its right edge is rather sharply defined. It even seems that some craters may have been partially erased there - this is going to be interesting to see at higher resolution:

Click to view attachment

If these dark/brighter areas are mostly albedo variations Vesta has remarkably big albedo variations.

It's going to be interesting to create DEMs of Vesta using stereo imagery once the raw image data appears at the PDS. Doing so should distinguish between topography and albedo variations (anaglyphs, more images or even false color images might do so as well).

Vesta now looks like a weird mix of Miranda, Mimas, grooved asteroids/satellites and possibly Hyperion to me. But mostly it's just uniquely Vesta.

A comparison view to show where we are...

Phil

Click to view attachment

... and a map. Very approximate and uncontrolled still.

Phil

Click to view attachment

Engines on again!

I can't help but get a sense of familiarity with those two large craters. Ritter and Sabine from Ranger has a close resemblance. In any case, the flat floored nature of the craters seem out of place on such a small body.

Aha, Steve G, that's what made them so strange-looking -- most of the craters on Vesta seem to be simple bowl shapes, but these do have flat floors.

Here's a cartoon of what I think I see. (Warning: this is more arm-wavey and speculative than my usual -- so it's probably wrong but I couldn't help but try to interpret this.) I'm not sure if the "head" of the snowman formed at the same time as the other two craters -- it looks more rounded so I think it predated the other two. But I think the other two formed at the same time (outlined in pink). You can see an area immediately surrounding the two craters that is almost devoid of impact craters -- that's the continuous ejecta blanket. Beyond that is the dark area that Bjorn noted -- that, I'm going to argue, is the discontinuous or secondary ejecta. I was puzzled about the lumpy looking deposit within both craters, which partially fills their floors -- I think that's where the two ejecta curtains of the simultaneously forming craters collided and piled up against each other so that all the ejecta wound up falling on the region where the two craters touch.

YMMV.

I don't think that could be correct, Vesta is not tidaly locked to anything. It rotates on it's axis every 5 hours or so. I think that part of the northern hemisphere is dark right now because it's "winter" there and the pole is currently tilted away from the sun. Anyone know what the figure on Vesta's polar tilt is relative to the ecliptic?

-kap

Edit: looks like we are still looking at the south pole, but the large impact crater is dark and we are seeing some of the surrounding features.

Wikipedia says 7 degrees to the ecliptic.
Phil's map implies that we should get some pretty good coverage of the north, I was worried about a Uranus-style scenario where we'd have nothing, that's not the case.

We'll be at the asteroid long enough for its 'seasons' to reveal the rest of it anyway.

Sorry to correct you, kap, but see here for an example. With tilted axis, each pole stays dark for half an orbit and then in the light for another half.

Taking into account that a couple of weeks ago we imaged the south pole, it is impossible that it is now in the dark. What you (don't) see here is the north pole in the dark and part of the northern equatorial region.

Regards

Ah I see, I just wrote a whole post about how I thought the dark area in this image: http://dawn.jpl.nasa.gov/multimedia/dawn_v...mage_072311.asp was the south pole and the image was upside down, but I just looked at it some more and I was incorrect, I just don't think I had the correct perspective in my head.

-kap

Thankfully, Vesta has a nice, clearly visible marker for where the south pole is

Yeah, I think the only big body in the solar system that does a nicer job of providing a visual marker of its coordinate system is Iapetus!

Ah, that is the inclination of the orbit to the ecliptic. The same article states an axial tilt of 29 degrees. Axial tilt is usually stated relative to the orbital plane of the object and not the ecliptic.

Almost like the thread on a lightbulb. Where in the solar system do you suppose it was screwed in?

Yeah, are we seeing some of Jutzi & Asphaug's (2011) "Mega Ejecta" here?

P

how things change! this was the first map of Vesta ever, compiled in 1983 from monitoring its spectrum over one rotation

Nice one! This map was made by Michael Gaffey by studying how the reflection spectrum changed as Vesta rotates. As he used an incorrect rotation period (twice the true period) it can't be easily compared with new maps, his features must be distributed differently. This specific map is a redrawing for Sky and Telescope. The original is in his abstract for LPSC in 1983, and it shows something not seen here... the south pole was tilted away from Earth at the time of observation, so here the map says 'no data' but Gaffey's original map labelled it "Here there be dragons". So now you know what lives in the south pole... sounds like the mountain should be called The Lonely Mountain.

Phil

the "here be dragons" map is here http://cdsads.u-strasbg.fr/abs/1983LPICo.497...14G

Don't forget Saturn's thoughtful provision of a marker denoting both its equator and the orbital plane of its family of moons.

Here is a magnified and sharpened look at the far right rim, giving a good cross section of the large trough. Another deep crater and a mountain which promises to be spectacular when we have a closer look. I added some sky to the picture so there is a less cramped feeling to the image.

The progressive orbit reduction through engine-controlled spiraling is clearly ongoing:

Press conference starting...