Big storm on Saturn Options

[john_s]

The solar system is a happening place this week! I just learned of a major storm in Saturn's northern hemisphere, being monitored by the usual band of talented amateurs. See this site for a list of recent images. Chris Go's site has a particularly nice image.

John

[nprev]

That's a big 'un! Is Cassini in any kind of a position (both orbitally & in terms of planning flexibility) to snap a few close-ups?

[volcanopele]

Of course it is in a position, but always remember, Cassini observations are planned months in advance and changes in the observation plan almost never happen (trust me, we tried). Near the end of Rev142, there are a couple of quick imaging opportunities with the WAC but nothing extensive. The storm should be visible during the December 24 observation. The next orbit, Rev143 has many more Saturn observations, so hopefully the storm will stick around till then.

[stevesliva]

I hate to ask this question, but I'm really curious. If Cassini had a scan platform, would on-demand retargeting be a lot more feasible? I'm thinking, yes, we'd simply be trading off imaging vs. imaging, not imaging vs. the whole suite. But I don't know enough about the sequencing. Would a spacecraft with a scan platform have a separate sequence for the scan platform that could be modified by itself?

[Toma B]

Maybe Hubble Space Telescope can snap some nice image of this BIG NEW STORM.
Does any member of UMSF knows somebody in Space Telescope Science Institute (STScI)?

[john_s]

I hate to ask this question, but I'm really curious. If Cassini had a scan platform, would on-demand retargeting be a lot more feasible?

It would certainly be simpler, but nothing in spacecraft operations is simple. There would still be numerous issues to be resolved- what pre-planned observations would be displaced, where would the data be put and when would they be downloaded, thermal implications of the new scan platform orientation would have to be checked, and new command sequences would have to be developed and tested. The Mars Rovers are always responding to new information on ~24 hour timescales, but they and their operations are designed from the ground up to be able to do that. Orbital missions are never that flexible.

John

[Ian R]

This seems to be a re-occurring phenomenon on Saturn - remember the large equatorial outbreak of 1990?

http://hubblesite.org/newscenter/archive/r...s/1991/1991/04/

Of course, English actor and comedian Will Hay is famous for (probably) being the first astronomer to observe one of these white spots, back in 1933:

http://en.wikipedia.org/wiki/Will_Hay#Private_life

[Juramike]

Nice shot of Saturn storm taken by Cassini (props to VP): http://saturn.jpl.nasa.gov/multimedia/imag...5/W00065990.jpg

Using the Solar System calculator to get the actual time of observation (caption indicated 1.323 M km away) sets it at 12/22/2010 23:40 UTC. This observation seemed like it would be nicely centered on Saturn's sunlight hemisphere and thus nicely visible from Earth.

Using a rotation rate of 10:47 h for Saturn, and propagating forward, here is an EXCEL table observation times where the storm should be centered on Saturn's visible disk on Earth. (Times are UTC and EST). Saturn rises around 3 AM and is better viewed closer to morning as it rises higher in the pre-dawn sky. I put "XXX" for view times where the storm is likely to be best. (Hopefully I got all the calculations right):

 Saturn_Storm_spotting_from_Earth__Dec_22_2010___Jan_4_2011_.xls ( 23.5K ) Number of downloads: 705

[Ian R]

Right, I'm off to eat my Christmas dinner...

[centsworth_II]

Right, I'm off to eat my Christmas dinner...

Thanks for the picture and... MERRY CHRISTMAS!

[nprev]

1. Wow. Look at that churned atmosphere! Remarkable.

2. Dude, Santa is like totally ripping that peak! Merry Christmas, all.

[antipode]

Wow. It looks a *little* bit like Karman vortex street. I wonder what its 'downwind' of

P

[volcanopele]

Images from December 24 are hitting the ground and the pages for them are on the JPL raw images page:

http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=230977

Enjoy!

Even more dramatic in the BL1 filter:

http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=230973

[Stu]

Fascinating...

Not really my planet, but I've had a go, just messing about really..

[ugordan]

My quick version using CB2/GRN/BL1:



EDIT: Ugh, that'll teach me to do color composites on a laptop screen... Image replaced with an improved version. I didn't want to use CB2 as full resolution luminance as the storm contrast is quite different from the visible channels, especially in the tail. Too bad it wasn't the GRN that was full res.

[nprev]

Spectacular!!!

I wonder if that thing is lighting up Saturn's magnetosphere as well...looks like it'd be a major lightning generator.

[ZLD]

Here's my take on the storm. Looks pretty massive. Used MT2, GRN, BL1 filters for color and the CB2 filter for luminance to maintain definition.


Edit: Whoops, I posted the wrong file. Fixed it with the version that doesn't look so crummy in the darks. I'll work on a better version in a bit.

[EDG]

It's interesting to see how "untidy" it is compared to say the GRS on Jupiter. Very nice pictures though.

[Shaka]

Yeah, that was one 'badass' big pigeon!

Next year I'll buy it a present.

[Bjorn Jonsson]

It's interesting to check earlier Cassini images to see if there are any images showing how this new feature formed. I imagine it might have started as a small, bright spot.

Unfortunately there do not seem to be many images of Saturns this month but I found these images from December 5:

http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=230356
http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=230355

A small, bright spot appears in both of the images so it is real. It's located at approximately the 'correct' latitude but I don't know if this is the same feature - this could be determined if I knew the subspacecraft longitude.

I'm aware it's very difficult to change observations that were planned months in advance but this is a *really* interesting event. Hopefully there are enough Saturn observations planned for the next rev. I remember some quick changes to Galileo's observations in response to unexpected events, e.g. the loss of the E16 Europa imaging (some of the originally planned E16 observations were incorparated into the E17 observations) but I imagine the Cassini obervation sequences must be far more complex than Galileo's.

[volcanopele]

Yes, that's the same storm, right about the time the RPWS first detected lightning from it.

There are many more Saturn observations during the next orbit, but I have no idea yet on whether they will show the storm, if it is still around.

[ZLD]

Heres a bit clearer version of the storm. False color with stacked images and some noise suppression. Filters, MT2, GRN, BL1, CB2(lum) again.

[antipode]

Wow

So are we seeing high cold[er] cloud tops punching though the normal aerosol/haze layer here?

P

[nprev]

So it would seem.

Question to anyone knowledgeable: Is the storm drifting within the larger atmosphere like the GRS, or is it fixed in longitude? Reason I ask is that it looks very much like a plume of sorts in this image, with the prevailing winds peeling off material from the top of the emission.

Would be interesting indeed if this is a manifestation of some sort of surface disturbance (whatever the word "surface" might mean on Saturn, if anything...)

[Hungry4info]

Anyone noticed the moon shadow? Not nearly as impressive as the storm but still moderately noteworthy.

Attached thumbnail(s)

 

[volcanopele]

Yep, that's Dione's shadow.

[volcanopele]

Question to anyone knowledgeable: Is the storm drifting within the larger atmosphere like the GRS, or is it fixed in longitude? Reason I ask is that it looks very much like a plume of sorts in this image, with the prevailing winds peeling off material from the top of the emission.

From what I've read, it is drifting about 2-2.5 degrees to the west (the head of the storm I mean) each day. So the System III longitude increases by that amount each day.

[Juramike]

Ground based image (Celestron C14 I assume): http://www.flickr.com/photos/31167687@N02/5299087913/

[nprev]

Thanks, VP, and wow, Mike! The sheer scale of that thing is just jaw-dropping in this view!

[antipode]

Holy Moly! One of the images/events of the year - and right at the 11th hour too.

Ground based obs are going to produce some spectacular movies as they track the evolution of this baby...

P

[Juramike]

Well hot diggity-dawg, that EXCEL file posted above worked!!! One of our local amateur astronomers used it to image Saturn and snagged two timepoints:

http://www.raleighastro.org/gallery/main.php?g2_itemId=4342

[Mr. Milton Banan...]

Hi folks! This is my first post to this board. I happen to be fascinated with violent weather on other planets-in particular, thunderstorms. I'm wondering if this is what this particular storm is-one massive thunderhead or a series of them bunched in some sort of titanic squall line. I note that similar massive thunderheads had appeared on Jupiter, supposedly towering 100 miles above the surrounding clouds. Those storms were also very rare. I hope that Cassini can do radio readings to check for lightning bolts. If there are lightning bolts in this storm, it wouldn't surprise me if some of them were strong enough to incinerate a city! Flying alongside this beast would be a truly terrifying and awe-inspiring experience.

Another thought would be to photograph this storm when it's on Saturn's night side to check for lightning flashes.

It's too bad we can't do some sort of 3-D representation of this storm, so we could check out is vertical structure.

[jekbradbury]

A quick animation from the Flickr photos Juramike linked to (greyscale in order that the GIF not be banded or dithered):

[Juramike]

Here is my new and improved EXCEL spreadsheet for predicting Saturn storm visibility from Earth. It is based on ground-based observations and starts from Dec 10 and projects forward to Jan 24, 2011. (It correlates to images already acquired between Dec 10 and Dec. 27th.)

Assuming a "System II" cloud rotation rate of 10 h 39 min, the storm is tracking westwards 3 min every Saturn rotation. Effectively the storm is rotating around Saturn every 10 h 42 min as viewed from Earth.

The best views will be about 30 minutes or so before the storm is at dead center on Saturn's disk.

Enjoy!

 Saturn_Storm_spotting_from_Earth__Dec_10_2010___Jan_24_2011__UPDATE_20101230.xls ( 43K ) Number of downloads: 545

[Juramike]

Saturn in MethanoVision, using RGB[CB2, MT2, CB2xInvert(BL1)] from the December 24th observation:



Neat dark ring around the storm (downwelling, so more methane absorbance?) and some detail of a bright upwelling in the storm center itself.

[Mongo]

Hmmm...





Coincidence?

[Juramike]

Here is an animated sequence showing storm evolution from ground-based observations from December 14th to December 30, 2010:
http://www.flickr.com/photos/31678681@N07/5309489179/

See also:
Link to Trevor Barry's website here: http://trevsastronomy.webs.com/apps/photos...albumid=8090267
Link to Anthony Wesley's website here: http://www.acquerra.com.au/astro/

[Floyd]

From Rev143 Looking Ahead Cassini should get some more images of the storm between now and Jan 20.

" ISS begins its observations for Rev143 and the new year on January 2 as it performs astrometric observations of Saturn's small, inner moons. During this observation, the camera system will image Polydeuces, Telesto, Pallene, Prometheus, Anthe, and Atlas. Shortly before, the wide-angle camera (WAC) will image Saturn. The large, bright storm that formed in December 2010 in the North Temperate Zone of Saturn should be visible during this observation (though slightly farther to the west than shown in the graphic at right as the storm is slowly drifting to the west by 2.5 degrees per day with respect to the IAU longitude system for Saturn). ISS will take a similar observation on January 6, when the narrow-angle camera (NAC) will observe Prometheus, Anthe, Atlas, Methone, Calypso, Pallene, and Polydeuces. The Saturn WAC images should show the western end of the large northern storm."

There will be other images of Saturn on the 10^th and 15^th, but the storm will not be imaged unless it has expanded significantly.

[Juramike]

Blink animation of Dec 24 and Jan 2 in MethanoVision. The new spot to the E looks "fresher" (more white = less methane absorbance = higher cloudtops). This suggests a hot spot plume from a deeper atmospheric layer and the older storm lobes being carried westward?


[Animated GIF: click to animate]

The MethanoVision Jan 2 image can be seen here: http://www.flickr.com/photos/31678681@N07/...in/photostream/

[FatSplenda]

It would certainly be simpler, but nothing in spacecraft operations is simple. There would still be numerous issues to be resolved- what pre-planned observations would be displaced, where would the data be put and when would they be downloaded, thermal implications of the new scan platform orientation would have to be checked, and new command sequences would have to be developed and tested. The Mars Rovers are always responding to new information on ~24 hour timescales, but they and their operations are designed from the ground up to be able to do that. Orbital missions are never that flexible.

John

Ah! Finally, someone gets it.
I am part of the tactical uplink operations and engineering team for the Rovers, and I'm glad to see that it's understood how different these things can be!
Based on the little I know about Cassini (I've never been acquainted with its sequencing process either, other than its pointing design and control suite for attitude constraints), I would guess that having a scan platform has just as many pros as cons. The pros would obviously include increased science -- you no longer have to move the whole spacecraft -- and maybe reduced usage of the reaction wheels. Would be tough to say without a high-fidelity analysis there. The cons would be adding more analyses and sequence flight rule checks for the operations team, and wear and tear for the engineering team.
No such thing as a free lunch.
In any case... pretty pics!

[Floyd]

New set down.



[first edit] Can someone explain how to get the image reduced? I thought that happened automatically. I simply inserted address of this image with the insert image button.

[second edit] Image now correctly posted. Thanks ugordan, uploading as attachment works (The attachment function is somewhat counter intuitive as after you UPLOAD, you still have to go into the Manage drop down box and hit +). Thanks also centsworth_II, however, that thread was locked so I couldn't open/edit my old post to see what I had done. I post pictures so infrequently that I forget what I did previously by the time I post again--or maybe I post regularly, but my memory is so poor that I don't remember that either.

[ugordan]

You can't. If it's an inline image like that, it will be automatically reduced if it exceeds a certain size. It's best to either just post a link to it or upload the image as an attachment - saves bandwidth when viewing the thread and automatically produces a thumbnail image.

[centsworth_II]

Can someone explain how to get the image reduced?

It looks like you did it here. I guess that's the only way to post a small image that can then be enlarged by the viewer.

[Juramike]

Blink animation of Cassini views of the big storm on Saturn Dec 24 - Jan 2 - Jan 6:



[animated GIF: click to animate]

[nprev]

Beautiful, Mike; thanks!

Morphologically, this storm seems very similar in many ways to the 'curdled' features often seen trailing behind the GRS, although considerably larger. I find that striking; is it possibly significant?

[Hungry4info]

Additional images from Rev 143.
http://saturn.jpl.nasa.gov/multimedia/imag...5/W00066331.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...5/W00066332.jpg

Have we seen those ripples extending up toward the equator before?

[Juramike]

There's some beautiful belt detail in the last batch of raws. It is starting to look more like Jupiter.
Gotta figure a creative way to use the MT3, MT2, and CB2 combo set.

[Juramike]

Straightforward combo of HiPassMT2 RGB[MT3,MT2,CB2]. Some channel mixing between the methane transmission layers and a gentle contrast enhancement:
Blue is deep atmosphere (much methane absorbtion), white is upper levels (light reflected before methane can get absorbed) .



Amazing detail in this! The bright upwelling at the upper left of the image seems to have a dark spot in MT2 and MT3 images (eyewall??). Immediately to the SW of the upwelling is a deep blue vortex of descending air. Cloud patterns around this spot show a counterclockwise pattern.

And a shockwave can be seen trailing from the W edge of the storm down through the southern belt almost to northern edge of the the Equatorial belt.

[jasedm]

That's really nice Mike - quite some detail there, and yes, you can clearly see the shockwave propagating back from the storm's leading edge.

Awesome.

[Juramike]

Another shot of the storm on Saturn. Better view around the main "spot":



Taken from 1,000,000 km on January 12, 2011.

[Juramike]

Couldn't resist some interpretation/speculation:

[Guest_Sunspot_*]

Will they or have they changed any future observing sequences to get a better look at the storm?

[Ian R]

Latest colour view and video:



http://www.youtube.com/watch?v=suWzhUjvvgk

[Juramike]

Nice video!!

[volcanopele]

Grrr... now I have to make my own version of that

[Juramike]

The site for the Planetary Virtual Observatory and Laboratory has upgraded to a new server.

The new site is: http://www.pvol.ehu.es/pvol/index.jsp?action=iopw

[Juramike]

Updated spreadsheet for viewing Saturn's storm from Earth. The time is when the W edge of the storm cloud is at the center point on Saturn's disk as seen from Earth.

Spreadsheet good to Feb 28,2011. (Validated using observations from Dec. 14, 2010 to Jan 16, 2011).

 Saturn_Storm_spotting_from_Earth__Dec_10_2010___Feb_28_2011__UPDATE_20110120.xls ( 62.5K ) Number of downloads: 312

[Juramike]

I posted a detailed graphic comparing features of Jupiter's Great Red Spot to those of Saturns North Temperate Storm 2010: http://www.flickr.com/photos/31678681@N07/5385677331/

[Juramike]

Animation of Earth-based telescope images of Saturn's storm from December 14, 2010 to January 24, 2011:
http://www.flickr.com/photos/31678681@N07/...in/photostream/

[ZLD]

It looks as if Saturn may gain a temporary white band around the planet if the storm continues to expand. Should be very interesting to see the next images of this storm up close from Cassini.

[J.J.]

^
That seems to be the pattern: white spots blowing up, and fairly quickly spreading out into a latitudinal zone until it eventually loses its identity.

[Mr. Milton Banan...]

So, exactly what kind of storm is this? Is this a massive thunderstorm complex? It would be interesting to really get down to what this is, specifically. If the original spot is a massive collection of thunderclouds, does this mean that they spread out to create a band around the planet?

[Juramike]

I think there is a massive anticyclonic upwelling from a lower layer, and the white stuff is just the upper level turbulence and shear between belts and zones are making high clouds that are extending and encircling the planet.

Unless the upwelling is able to self-sustain, it'll eventually run out of steam (probably literally!) and the upper clouds will dissipate.

I may be wrong, but I think of this as a hurricane sucking in energy at a lower warmer level (where there is a cyclonic flow we can't observe), then moving it up the central column, where it pushes outwards at the lower cooler level. The whole thing driven by the upper and lower level temperature differential and the transfer of energy via condensation of ....water? ammonia?.

That's my guess...

[Mr. Milton Banan...]

I emailed Carolyn Porco to find out if they were going to investigate lightning flashes within that storm, and I was told they would attempt it. I wonder if it would be possible to check for lightning flashes from the night side of Saturn. Because...if this is an upwelling of thunderstorms, I'd imagine there would be some intense lightning there.

[stevesliva]

They "hear" lighting with the radio science instrument, if I recall correctly. As stated earlier, seeing it's a lot tougher with a still camera that they generally point at the daylight side of the planet.

[volcanopele]

The RPWS can "listen" for electrical discharges from lightning in the storm, but actually looking for lightning on Saturn on the planet's nightside requires dedicated observations that are planned 6-12 months in advance. Another issue to keep in mind is that the northern hemisphere is currently being illuminated by Saturn's rings, which can complicate lightning detection.

[Gsnorgathon]

And even the southern hemisphere is somewhat illuminated by forward-scattered light from the rings. (Though maybe it's no worse than night time on Earth illuminated by a full moon - I've never researched it.)

[ngunn]

It appears the storm now has a ghostly neighbour: http://saturn.jpl.nasa.gov/multimedia/imag...6/W00066521.jpg

[Ian R]

Here's a faux-colour version (CB-GRN-BLU), rotated so that north is at the 11 o'clock position:

[Juramike]

Animated blink between Jan 15th and February 4 images in false color [MT3,MT2,CB2]:



I think the "ghost" is a vortex riding the wake of the western edge of the storm front.

[volcanopele]

It appears the storm now has a ghostly neighbour: http://saturn.jpl.nasa.gov/multimedia/imag...6/W00066521.jpg

No, that's the same storm. It has just now met its tail.

[Juramike]

Whoo-woo! All aboard the storm train! Here's a non-time sequenced animation of the storm, ordered by faked Saturn rotation:


[Animated GIF - click to animate]

Sequence of images is 1/12, 2/4, 1/15, 1/15.

[nprev]

Wow. Damn.

Times like this I remember how back in the day the meme was that the outer Solar System was presumed to be nearly static for lack of solar energy...man, talk about a swing & a miss in SO many, many ways that we know about already, and probably a lot more that we don't know yet!

[Guest_Sunspot_*]

Are they going to get any high resolution images of it?

[Juramike]

Wow!!!

http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=233338

Lots of high resolution IR images down on the Cassini raws page.

[Astro0]

Quick stitch of 21 images. There's a whole lot more images in this sequence if some brave soul wants to make it

[Stu]

Wow... we've had MER Monopoly...

I think we just saw the first CASSINI Jigsaw...

Note to all: I had the idea first, and I'm in the middle of watching THE SOCIAL NETWORK, so no-one get any ideas about suing me in years to come, ok?

[Juramike]

Comparison graphic showing similarities/differences between the Jan 12 and Feb 23 Saturn storm observation:


Full resolution WAC MethanoVision RGB [Mt3, MT2, CB2] of the Feb 23 observation is here: http://www.flickr.com/photos/31678681@N07/5478172432/

[Ian R]

Just got back from London: drooled over Charlie Brown (not literally), gawped at Ralph's penetrometer -- and even touched a chunk of the Titanic's hull!

Oh, and here's a quick RGB composite from this latest, bountiful, batch of raws:

[djellison]

gawped at Ralph's penetrometer

And that's the flight model. The flight-spare is sat on Titan

[Ian R]

Or embedded in Titan, I suppose!

...and here's RGB storm composite number two:

[Juramike]

Saturn RGB[RED,GRN, BL1] composite Feb 25, 2011. Details enhanced with a HiPass filtered overlay of the CB2 IRP90 image:

[Juramike]

Composite of images in the CB2 IR band taken from Feb 23-25, 2011 coordinated and stacked to show the full length and features of the massive storm:

[Guest_Sunspot_*]

In terms of scale how does this storm compare to those that have previously appeared?

[Ian R]

Nice work Mike!

Here's a false-colour NAC view of the head of the storm (MT2/CB2/BL1):

[Ian R]

Another WAC, RGB view, with one of the moons (Enceladus?) just lurking below the left ansae:

[Guest_Sunspot_*]

Are the clouds in the storm moving fast enough to cause some motion blur in the images?

http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=234025

If you take a look at that image, the cloud features on the left have sharp boundaries, the clouds in the storm look very soft - like motion blur?

[Ian R]

Prequel to my last post:

[john_s]

Are the clouds in the storm moving fast enough to cause some motion blur in the images?

It sure *looks* like motion blur, but I don't think the numbers work out. The resolution of that image is about 20 km/pixel, and typical Cassini ISS exposure times for sunlit objects are maybe 1/100th to 1/10th of a second. So to get a couple of pixels of blur would require cloud speeds of 400 - 4000 kilometers/second- the clouds would exceed escape velocity.

John

[volcanopele]

CB2 frames are 3.2 seconds exposures. MT frames are longer IIRC.

[Juramike]

Random question: But why are the MT3 images usually smaller?

[volcanopele]

To improve signal to noise. Not a lot of reflected light at that wavelength.

[Juramike]

RGB[MT3,MT2,CB2] composite of 18 contrast-adjusted images from the NAC view of the storm complex.



Full resolution (and there is lots of neat swirly detail) here: http://www.flickr.com/photos/31678681@N07/5488190012/

[jasedm]

^ Oh that's a work of art!

Beautiful.

[john_s]

CB2 frames are 3.2 seconds exposures. MT frames are longer IIRC.

Mea culpa! Still, for 4 second exposures you'd need 10 km/sec (22,000 mph) winds to blur by a couple of pixels, so I think we still have to conclude that the storm clouds are intrinsically "blurry"- overlying high cirrus, maybe?

John

[machi]

RGB[MT3,MT2,CB2] composite of 18 contrast-adjusted images from the NAC view of the storm complex.

"Oh that's a work of art!"

Impressionism?
Simply fantastic, I want this "painting" on the wall!

[Shaka]

Ditto!
I'd love to sneak it onto the wall, unlabeled, at MOMA, and overhear it being discussed by the art crowd.

[Astro0]

Just for fun

[Stu]

Gorgeous! I started making that myself but halfway along the strip I was getting one of those headaches you get after eating ice cream too quickly...

[toddbronco2]

Just for fun

Thanks Astro0! I was hoping somebody would put together a panoramic view of the storm from Cassini's recent images