An Australian imager has captured what appears to be a fresh impact scar on Jupiter:

As luck would have it, I couldn't make the trip with my 3RF group to McDonald Observatory tonight, but those of us who did make it will shoot for a confirmation using the 82" Struve telescope.

Wouldn't that be cool?

Jeff, 

What a find!  Is north up in the image?  At what time does the possible scar transit?

Dave Mitsky 

I think North is up, that looks like the SEB below the middle and the GRS over to the left.

Looks like the scar is an hour or two ahead of/behind the GRS. I'll take a looksee to figure out the GRS transit time.

All I have to go by is the image. It was sent to me via the RadioJove listserv and that's all I have. There is the possibility it could still be radiating, so the Jove guys are setting up a coordinated observation for the next 24 hours to see if there is residual noise they can catch.

Anyone with a big gun should try to see it tonight.

EDIT: GRS transit times are:

23:46 UT July 19, 2009

09:42 UT July 20, 2009

Since I don't know whether the scar is leading or trailing, bracket those times by 2 hours for the best possible view.

Spaceweather has more on this now. South is up in the image. Anthony Wesley reports an image from two nights ago doesn't show the feature.

Did we know this was going to happen, if it's confirmed it was an impact?  Or did it sneak up on us? 

It was a surprise. Anthony Wesley, the discoverer as far as I know, imaged Jupiter two nights back and it wasn't there, and then again today and it was. It shows a fan shape "downstream" so it was several hours old by the time of the image.

I know some amateurs in Melbourne and nearby, from 3RF, and they know Anthony. I think they're planning a mini-star party down there tonight (their time) to try again.

A Texas 3RF volunteer contingent has just arrived at McDonald Observatory to use the 82-inch telescope there, so they're in for a nice surprise from the team leader, with whom I shared this news a few hours back. I'm hoping they grab some nice high-res photos tonight!

This news has made its way around this afternoon via various listservs, so somebody somewhere in the world should have some nice images online tomorrow ...

... and, if it's another disrupted comet or asteroid, there could be more in store ... that would be great!

 Such reports always get some of us pumped up.

Doesn't look like I'll have very fevorable sky tonight, tomorrow night might be better.

This will be well worth watching.

Yeah, and it's neat knowing that probably more eyes than usual will be on Jupiter tonight as it passes over our separate horizons!

I will post something here within a few minutes of getting reports from our folks at McDonald, though it may be sometime tomorrow before they can send images.

Hey Jeff, is it normal for an impact to go under the radar?  I was kind of under the impression that the genius phycisists and mathematicians were able to calculate body's trajectories, such as the comet Shoemaker-Levy 9.  It seems frightening that we didn't know what seems to be a body of substantial proportions was heading for Jupiter.  Do you know how much of the solar system is logged, meteors, comets etc.?  And how much of the solar system is kept a watch over if orbits change or something anomalous happens?  Thanks Cory

The search for possible impactors has thus far been limited to the regions of space from which they'd threaten Us, not Jupiter. In fact, when Shoemaker-Levy 9 was discovered, it was previously unknown. Not only that, but it took a good deal of data gathering and analysis to figure out that it had previously orbited Jupiter.

So, yes, we get surprised ... unfortunately, rather often.

We don't know yet how big that spot actually is, or what size range and velocity range the impactor would have had. But probably something like one of the fragments of SL-9.

Wow.

Unless someone unearths a stack of images made in just the right places over the past few days, we may never know whence the impactor came. But there is a family of Jupiter-orbiting comets, and there are errant asteroids galore (we don't know how many), so there is a wide range of possibilities.

Orbital trajectories require observations to be calculated.  Comet Shoemaker-Levy 9 was discovered serendipitously.  This recent impactor was not.

I came across transit times for the impact site on a Yahoo!Group to which I subscribe.

Dave Mitsky

The list below shows times (in UT) when the spot crosses Jupiter's
Central Meridian. This prediction assumes a stable longitude of 216 degs
in System 2 as shown on Anthony's image.

WinJUPOS 8.1.8 (Jupiter), C.M. transit times, 2009.07.19 19:17
Object longitude: L2 = 216,0° + 0,0000°/d * (T - 2009 Aug 01,5)
Time interval: 2009 Jul 19,0 ... 2009 Aug 01,0
Output format: Date UT (C.M. of System 2)"
------------

----------------------------------------------
2009 Jul 19 06:09 ( 216°) 16:05 ( 216°)
2009 Jul 20 02:00 ( 216°) 11:56 ( 216°) 21:52 ( 216°)
2009 Jul 21 07:47 ( 216°) 17:43 ( 216°)
2009 Jul 22 03:38 ( 216°) 13:34 ( 216°) 23:30 ( 216°)
2009 Jul 23 09:25 ( 216°) 19:21 ( 216°)
2009 Jul 24 05:16 ( 216°) 15:12 ( 216°)
2009 Jul 25 01:08 ( 216°) 11:03 ( 216°) 20:59 ( 216°)
2009 Jul 26 06:54 ( 216°) 16:50 ( 216°)
2009 Jul 27 02:45 ( 216°) 12:41 ( 216°) 22:37 ( 216°)
2009 Jul 28 08:32 ( 216°) 18:28 ( 216°)
2009 Jul 29 04:23 ( 216°) 14:19 ( 216°)
2009 Jul 30 00:15 ( 216°) 10:10 ( 216°) 20:06 ( 216°)
2009 Jul 31 06:01 ( 216°) 15:57 ( 216°)
----------------------------------------------------------
courtesy of:
-----------------------------------------------
Hans-Joerg Mettig, Kirchzartener Str. 28,
D-79117 Freiburg im Breisgau
http://jupos.org

Thanks, Dave!

I relayed to our team at McDonald. They're gonna set up a small scope outside the dome and monitor as soon as Jupiter is high enough to see. It'll take another two hours after that to clear the dome wall/slot. They're reporting <1 arcsec seeing there tonight! Woo-hoo!

Just want to say tks Jupiter as a guard in our history, otherwise, we all extinct for long time ago. But  how many people know today danger in our world ?

Oh, man, just as the critical hour approaches there are storms moving over McDonald Observatory and they've shut all the domes! If the team can hang out for another two hours things should improve for a couple of hours but I don't know about the cloud cover ... Dang!

Bummer ... looks like the team at McDonald was rained/hazed out at just the wrong time tonight. They are going to reconvene after a few hours sleep and compare notes about any visual sightings, but no images apparently.

I never heard back from Pete in Selsey, UK, so I don't know if he managed anything.

And it's still daylight in Australia, although our guys down there have a session planned for tonight, their time.

Watch spaceweather dot com for info today. Surely somebody, somewhere had good weather!

 Lightening storms here as Jove would have been transiting,

I just came in after some visual observing, sky is still boiling, no way to detect anything.Around 10:00 to 10:30 UTC. 

I am a beginner with 10" dob. My sky is excellent in Canada. I do not have photo equipments.

I tried hard to find the black spot around 2:30 - 4:30 a.m July 20 pacific time with different filters but I did not see anything (for me only). Do I get the right time ? No chance to watch again.. stat to bright already.

Ming:

I am a beginner with 10" dob. My sky is excellent in Canada. I do not have photo equipments.

I tried hard to find the black spot around 2:30 - 4:30 a.m July 20 pacific time with different filters but I did not see anything (for me only). Do I get the right time ? No chance to watch again.. stat to bright already.

 The impact site (if it is) is far in the South Polar region. It's going to take very good seeing to detect it visually I think.

Has anyone else thought about Shoemaker-Levy happening almost 15 years to the date of this impact?  Doesn't seem all that long ago............

Has anyone taken any 'follow up' shots of this yet?

Scott (sure would like to see them) B

Yes, check out the ones linked at Spaceweather today (mostly from the UK).

Most visual reports I've read say "nothing there" today, but most of those were attempted at the wrong time.

An Australian group is trying again tomorrow night. Unsettled weather is over me tonight.

Our group at McDonald Observatory last night/early this morning was clouded out at the right/wrong time ...