Take a look at these images. Im not sure whether it might be "lens flare", which i've seen in quite a few images, or perhaps something else. What do you think?

http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=49058

http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=49059

I think you're might be right.

In the second image with Saturn's limb (?) the rings are viewed from a different angle, showing clearly that the light whisps are related to the rings. They have also remained in the same position relative to the rings. They can't be lens flares or image artefacts.

This was an opportunity I could not pass up -- I opened the images and took them out to two rings people here in the foyer at the DPS meeting, and they both got very excited about them. There are indications that something may be forthcoming from ISS about this already but it's all very hush-hush. There are still people in the poster session right now with posters explaining why spokes haven't been seen yet!

The rings sessions are tomorrow morning. I wonder if anything will be said there.

Anyway, stay tuned...

--Emily

COOL !!! Keep us upto date, hehe

I imagine that, from the point of view of the folks on the imaging team, this is a pretty good argument in favour of occasionally keeping an eye on these forums when time permits. Although most of us obviously don't have as strong a grasp of the subject material as they do, my guess is that, collectively, we probably are more numerous.

With so many Cassini images being available on the main site, it stands to reason that from time to time one of us will spot something that has been overlooked for one reason or another.

Good eyes, Sunspot.

I can promise you that members of the imaging team do lurk on sites like this one (not just me), maybe not to check on what others may have found, but to see if news has gotten out with the raw jpegs available on line.

Interesting timing, ring spokes are spotted just before Cassini's orbit is realligned with the ring-plane. We won't be able to see them again for nearly a year.

Obviously, there is an advanced species in the Saturn system that uses ring spokes as a mode of communication. The Voyagers caught them by surprise, so they didn't get a chance to hide them. However, they were prepared for Cassini, and have been able to keep from using the spokes up until recently. All I can figure is that they have an urgent message that must get out, or they mis-timed Cassini's return to the ring plane. Either way, we caught them!

This is why amateurs astronomers can play a role in the whole story.
Remember that many comets or asteroids were discovered by amateurs, including on images from professional observatories or satellites. In some cases even professionals ask for the help of amateurs. Professional astronomers are bound by their funding, sometimes they cannot do certain things because they have no time alloted for them.

Especially nowadays, with missions returning SO much data, I think amateur eyes are going to become increasingly important. Anyone in "the business" who stops a moment to think about the fantastic amount of data that is going to be returned from Mars Recon Oriter just goggles. They know that the team can't look at it all by themselves. There's got to be a way that the power of all these amateur eyes can be harnessed to help spot interesting stuff in the data.

Ring sessions at DPS start in a couple minutes--I'm on my way over!

--Emily

Update from DPS:

Jeff Cuzzi (rings interdisciplinary scientist for Cassini) just gave an introductory talk about the rings, only briefly mentioning spokes. After his talk, someone, I don't know who, asked: "I have heard that the spokes have reappeared in the last two days." Jeff said only "I have heard that too, and that [reappearance] may constrain models" for how the spokes form. Very, very carefully quiet. I expect we will be seeing a big splash from ISS before too long, but the poor guys are also swamped with their T7 data coming down and to make it worse all the biggest players are here and are probably traveling tonight and tomorrow so everything's probably a bit chaotic...

Also, just to clarify something, the rings people I spoke with last night had already heard through other channels that the spokes may have reappeared. But they hadn't seen the pictures yet.

--Emily

What are those things? Examining the images closely, all I can see is that on some of the lighter rings there is a notable increase in brightness, which appears to be arranged in two rays radiating out from approximately the planetary center. But it seems too far-fetched to assume that some weird force is rearranging or reorienting the actual material of the rings in such a way that they reflect more light. Could it be that some material is being deposited on or just above the surface of the ring plane that is more reflective than the rest of the rings? Is it possible that there is some mechanism for redistributing material into or among the rings?

I was thinking perhaps visualisation of field lines courtesy of charged particles?

Doug

Something like this in astronomy is the American Association of Variable Star Observers (AAVSO). There are a lot of variable stars out there - more than pro's can deal with. Amateur astronomers who belong to AAVSO are assigned a variable star (or stars) to observe every time they get a chance. Each time they look at the star, they record its magnitude (or brightness). Over time, a "light curve" is generated from their observations that can characterize the star's behavior. This data can then be passed on to the professional scientists, who don't have the time or the equipment to do the observational "grunt work".

The important thing about AAVSO is that it organizes and standardizes the observations and the data, so that the product the pro's get isn't just a random collection of non-uniform stuff from potentially unreliable sources.

Similar to AAVSO is ALPO, which specializes in lunar and planetary observation.

I could see something like AAVSO or ALPO for us planetary image junkies - a central clearing house that collects, standardizes, and organizes image analysis by amateurs to be passed up to the pro's. Probably a lot of work for those who run it, but it would be a valuable (and fun) tool!

A friend of mine relied on AAVSO observations as part of his thesis into Cataclysmic Variables. He's an X-ray astronomer now, but the visual reports really helped.


Doug

Carolyn Porcois at the Oxford Playhouse in an hour. I'm gonna swing by and see if there are still tickets availbale. You've got about 15mins to post any questions you might like me to shout out during a Q+A.

"The forum run by that nutter who asked about the spokes on Saturday morning thinks it's found pictures of the spokes possibly reappearing..."



Doug

Willl do... i've got a printout of that fig so i can so i can quote the ref number... You want me to mention the forum by name?

Right I'm off now, i'll take notes and report back after.

Be careful, the image number on the JPL raw images page differ from those we use. The JPL images are number sequentially, while the image numbers we use have the spacecraft clock time.

Nice idea. At first glance, the only serious problem I can see with implementing it is that interpreting an image of Tethys, or Iapetus, or the rings, is substantially more complicated than approximating the brightness of a variable star, or even discovering a comet. Thus I think we would need a bit more of a "safety net" than the AAVSO.

It might be a good idea to assign any given group of images to more than one volunteer. That way, if one of them missed something important, one of the others might pick up on it. This of course assumes there would be enough volunteers to go around, but somehow I doubt that would be too much of a problem.

Orient me here-- the second image show the limb of the dark side of Saturn with the sunlit side of the rings in behind the limb? Which ring are we looking at?

Interesting, but I'm getting dizzy trying to figure out where the heck we are...

--Bill

There is already an active and successful group of armchair amatuer astronomers with hundreds of discoveries under their belts -- the SOHO comet finders. I am not a comet finder myself, but I have been logged onto their message board for a long time and understand how they operate. It is suprisingly informal with the key communication medium being a bulletin board not dissimilar to this one.

The other key elements are:

-- a well written description of the minimum set of observations that are acceptable for confirmable submittals.
-- good notes for newbies.
-- a web form for the actual submission process.
-- a person on the SOHO team that is responsible for the confirmation process.

Note that this process is not continual or real-time. The confirmer occasionally gets bogged down for weeks or even months with other work. The submitters just have to be patient. However the success of the program is not to be denied and therefore it is now an attributed part of the SOHO science results which is pretty amazing since the project scope never included the search for new comets.

Oh. One more important note. The submissions are logged immediately on the web in a prominient Recent Reports link. The active members do a pretty good job of checking each other's work which I am sure is a great boon to the process.

Learn more at http://ares.nrl.navy.mil/sungrazer/

Just got back from the Carolyn Porco talk, It was very much a Sagan style talk weaving in and out the relationship between the casssini exploration of saturn and cosmology more broadly. Image and info wise there was nothing you wouldn't have seen or known if you had been following the mission on the JPL and ciclops site. The crowd did ooh and ahh occasionally and it was nice to see the pictures on a big screen.

There was limited time for questions at the end, and with a majority non-geek audience these were somewhat banal. As for the spokes, someone else go there first but not specifically regarding the images taken recently, she replied they hadn't seen them yet, i doubt she would have announced it at an event like this anyway. I think we'll probably have to wait for a press conference.

However one interesting bit of info did crop up in response to a question about the end of the mission, Ms. Porco indicated her favorite option (and i think in this context favorite does not mean most probable) was attemptiong a soft landing on Pan. Soft landing on one of the moons was certainly not something i had heard mentioned before as a possible mission end scenario.

Another project where volunteers shine: Spacewatch's FMO Project

Help finding FMOs (Fast Moving Objects) from fresh images taken by the Spacewatch telescope. Computer algorithms can't detect FMOs properly because they generate long streaks during the image exposure (they can be easily confused with edge-on spiral galaxies, cosmic ray streaks, image artefacts etc.) Many near-Earth asteroids have been discovered during this project.

Yet another cool volunteer project: Clickworkers

Help determining the ages of different Martian terrains by marking craters. The pilot study, Viking orbiter images are marked several times, but there are large amounts of MGS images to check. You can also classify craters.

Wasn't Carolyn Porco the one who first discovered the spokes in Voyager images? I remember she was interviewed about them in BBC's The Planets series.

Soft landing on Pan? So insane idea that it almost sounds cool.
I wonder how the probe could do that without breaking up by the ring particles.

Yes indeed.

Did she say "I never have to put a slide about spokes in my talks because I know someone will always ask about them" ?

Doug

I think I can surmise what Dr Porco is thinking (in part at least) with regard to a soft landing on Pan. A soft landing on any of the bigger moons would be pretty much impossible, as their gravity wells have got to be deep enough to turn a landing into a lithobraking (cryobraking?), barring some fancy manoeuvring from Cassini. Pan is a good choice there.

More importantly, getting in close to Pan would give us some incredible shots of the rings, and, once close enough to Pan's orbital speed, we'd almost certainly get the Holy Grail -- individually resolved ring particles, possibly moving slowly enough across the field of view to make following their motion and rotation feasible. THAT would be spectacular, and a fitting end to the mission.

If we're going to be ambitious enough to propose landing on Pan, though, why not go the whole distance and try to put the thing in _orbit_ around Pan for the first while before attempting the landing?

So I guess that means two questions:

(1) Is it possible to slow Cassini enough to get into orbit around, or land on, Pan? And, assuming that one's a "yes" --

(2) Would the imaging team be willing to sacrifice Cassini if there was still enough propellant left to get the ship that close to Pan?

I guess we all hope that the end of the mission is still a good long number of years away, but it's neat to speculate about it.

Rob:

Early Cassini EOM scenarios also included escape from Saturn, with (unnamed) planetary (etc) encounters!

Some arguments against leaving the environs might well be expected...

Apropos of EOM, there is a well worked out plan to de-orbit the ISS (in the great tradition of Mir, if not of Skylab). I suspect that, much though the space science brigade would like to do that thing sooner, rather than later, there might also be some arguments against an ISS oceanic encounter...

Bob Shaw

You're seriousley saying that even the Cassini imaging scientists haven't seen these images yet? And they went unnoticed until I pointed them out here in this forum? LOL

Well, these guys spend all day staring at Saturn images, so it seems like a quite a large assumption that the images in question were overlooked. Perhaps she was just keeping hush hush until an official release from NASA/JPL can be arranged, who knows.

Hmm. What kind of precision could we achieve here, Bob? Enough, for example, to land ISS on top of Richard Hoaxland?

Hey, that way he would finally get a close up look at a real spaceship -- a dream come true!

This in itself is an argument against an oceanic drop zone for ISS, I think. (Actually, I was originally kind of hoping they'd drop it into the Northwest Territories. For old times' sake.)

[Long after the fact edit: Changed Hoaxland's name to keep away Googling kooks.]

Rob:

It'd be a high price to pay if the ISS landed on a certain individual, but with some effort I might, just, be persuaded to bear it...

Oh, the pain! (NOT!)

Bob Shaw

PS Howsabouts a sort of global lottery-cum-nomination arrangement, you buy your ticket and name your victim, see? This could have legs, you know...

Assuming for a moment that Pan isn't in the Encke Gap, you could use a Titan flyby to drop the periapsis of Cassini's orbit to Pan. But then even if all the remaining propellant is burned, my SWAG is you'd get only a few percent of reducing the apoapsis of Cassini orbit from Titan down to Pan.

With a Prometheus propulsion, you might be able to get a spacecraft down to just outside the F ring. The orbit would have to be inclined with the node crossings at periapsis and apoapsis to avoid "ring-braking". Then, you'd still need a high energy burn to skip the apoapsis over the F ring, then an even bigger burn to skip the apopasis across the outer A ring. Then, finally a burn to zero the inclination. That is a lot of gas. It also assumes being able to thread thru a clear lane in the Encke Gap.

With a Prometheus alone, a more interesting orbit would have the apoapsis outside the F ring, the periapsis inside the D ring, and inclined just enough to avoid ring material near the node crossings at periapsis and apoapsis. The spacecraft would skim across the entire width of the rings on the sunlit side in one direction and on the back side in the other direction. The wide angle views across the rings would be like the view during Cassini SOI but even more spectacular.

Dr. Porco's comment may have been wishful thinking. I would be pleasantly astonished if Cassini could really do this.

Although there are a LOT of Cassini images, unlike with some missions there aren't so many that a scientist who's spent a good chunk of her professional life developing and sending an instrument to Saturn won't be looking at all of them. Especially since she's a rings scientist! While it may be possible that Carolyn doesn't look that close at every single smudgy Titan picture, I'd bet you a good bottle of wine she gives a very close look to every single rings pic that comes down as soon as she can, whether they're designed for ISS observations or whether they're just riders to CIRS or UVIS imaging. I'm sure she saw those features right away, and is only waiting to say something about them to confirm or deny whether they're The Return of the Spokes until she can make a good big media splash about it. Carolyn more than many scientists is in tune to the media and is very intent on making as much as she can out of every discovery made in an ISS image. Which has funny conflicting results. On the one hand, she is able to get really cool stuff about Saturn broadly covered in the media, no small feat in the midst of other compelling stories going on. On the other hand, it forces her to be careful to be silent about results until she can time an announcement well. Dealing with the media can be a real pain (she said, sitting precariously on the fence between being in league with scientists and being media).

Still, that doesn't diminish your sharp-eyed independent spotting of those marks across the rings, Sunspot! Well done!

Emily

How many of the Cassini images actually get posted on the "Raw Images" section of the main website, Emily? Since on average we get maybe a dozen or so a day, I had always sort of figured that we only see a fraction of them, and that what we get is probably based on:

(1) what the imaging team had time to put there, and,

(2) what would, or wouldn't, burn anybody's research by letting the cat out of the bag before they could get it into review, or at least present a conference talk. Hence my thinking that the images containing the spokes (if in fact they are spokes) might have "slipped through" unnoticed, mistaken for lens artifacts, as Sunspot suggested. Is this wrong though?

Jason has mentioned in the past that some members of the imaging team actually check in on the raw images website to see what has and hasnt come down, so would could infer that they all go on there.

Doug

Potentially interesting...

http://www.aas.org/publications/baas/v37n3/dps2005/632.htm

A bit off thread, but...

Some of the abstracts in the conference schedule Bob has cited above are pretty interesting. One that I particularly liked was at the end of (I think) section 47, one of the icy-moons colloquia. It's by some Brazilian folks who have looked into why Enceladus doesn't have Trojan satellites. Their calculations indicate that any Enceladan Trojans would have their orbits de-stabilized by Mimas any time Mimas and Encelaus crossed a mutual resonance (which seems to have been often).

Wonder if anyone's done this for Rhea?

http://ciclops.org/view.php?id=1435

Very cool stuff.

Kudos to sunspot for keeping us ahead of the curve... well spotted dude.

What's the equivalent of a Mars Bar for Saturn? Whatever it is, Sunspot gets one!

A polo? It looks a bit ring-like



Awarded for exceptional ring news

Doug

*This is great news. Yay! Have been hoping and waiting for this. On the dark side of the B Ring, huh? Well why not? Cassini (and Huygens) has been such a fabulous mission. And we've years to go.

Dr. Carolyn Porco, Cassini imaging team leader at the Space Science Institute in Boulder, Colo., and one of the first individuals to study spokes in Voyager images, was attending the Division of Planetary Sciences meeting in Cambridge, England, when she was informed of the discovery by her staff members. "This is really a joy, and very unexpected," she said. "It takes me back to my early days on the Voyager mission."

http://www.spaceflightnow.com/cassini/050917spokes.html

An accurate retelling of events would be...

Sunspot spots a spoke, Emily shows it to people at DPS, People at DPS tell CP

They only told half the story really - and the full story would have been more interesting and a credit to the policy of putting raw images online.

Doug

Am I right in recalling that you asked a question somewhere about spokes appearing shortly before Sunspot's spotted them but were promptly put in your place when it was pointed out that it was too early to see them?

Well - not put in my place, but I did ask on the Sat before the Thur when Sunspot found those images - and she said they didnt expect to see them till next year

She didnt know who I was w.r.t. this place though.

Doug

Yes, how about following the spirit of pro-am cooperation found elsewhere in astronomy. Examples would include the discovery of comets as well as project SERENDIP, where anyone with a PC can potentially be credited for discovery of extraterrestrial radio signals, by processing Arecibo radiotelescope data on their PC. I'm sure there are other examples out there as well.

Hi folks-

Just wanted to follow-up on this thread concerning who has seen what in Cassini images to say that some associates of the Cassini Imaging Team *do* check out sites like this one to see what’s being talked about, since we like hearing how excited everybody is about our images and the products we produce.

I think you need to know that the team does view every image that comes down. We have to, since it is our job to process images for public consumption and to publish any new scientific results. So we can assure you that there is no danger of our discoveries getting lost.

Also, Emily has got it exactly right: the team often needs to wait before officially announcing a discovery, either because of the delay imposed by the NASA review process or because they are trying to work out the significance and the science of the result.

And in any case, it’s meaningless to talk about who saw what first. Maybe you guys don’t realize it, but the Imaging Team members designed the experiment, planned the observations and they catalog and process the data. So they’re the ones who’d be credited with any discoveries made in Cassini images, regardless of who sees something first. That’s just FYI, not meant to be rude! So, continue to have fun, but know that the *main* reward the scientists get is to see the data first, have the first crack at it and then publish their results.

Well, that’s all I really wanted to say for now. Keep up the excitement, there’s lots more to come!

Cheers,
Preston Dyches
CICLOPS