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"wave" distortion patterns in Cassini ring images



 
 
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  #11  
Old July 3rd 04, 05:22 PM
Bruce Palmer
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Henry Spencer wrote:
In article ,
Revision wrote:

On the plus side, the mission
cost "only" $3.3 billion and likely would have been much more if the
original design had prevailed...



Moreover, it only barely survived as it was -- it would probably be dead
and largely forgotten, like its brother CRAF, had not the Huygens probe
represented a major international commitment that was difficult to cancel.


I remember that. ISTR somebody at or near the top of the Eurpoean space
heierarchy sent a letter to somebody in the U.S. that said "You *******s
better not back out now! We busted our asses on this thing and if you
pull out now you'll have zero credibility left with us." (One can only
imagine the reply such a letter would elicit today.)

I also remember the groundswell of tree-hugger opposition to Cassini's
launch from those who feared the spread of radiation if there was a
launch failure, or if the subsequent earth flyby missed and sent
plutonium streaking across the sky. They made a lot of noise and even
had a "Stop Cassini Now" campaign and petition with a fair number of
signatures on it IIRC.

So the naysayers' signatures wound up being recycled into toilet paper
while some of *our* signatures ended up going to Saturn. It turned out
pretty well I think.

--
bp
Proud Member of the Human O-Ring Society Since 2003
  #12  
Old July 3rd 04, 05:26 PM
DeSelby
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Dr. Porco explained them (in layman's terms) on NASA TV, and she didn't
seem fazed. It's regular "interference" from within the camera circuitry
and should be easy to filter. It appears to me that the waves show up
the most on the images which contain the least amount of light such as
the dark-side ring photos. Notice there is no interference on the bright
side photos.

Now what I want to know is when are the Titan images gonna show up??
The official site says the images are going to be downloaded Friday
afternoon - did they mean Saturday afternoon? Can't wait to see those,
unless they're all optical in which case they will probably be pretty
boring!

Leigh Orf, space nut
Assistant Professor of Atmospheric Science
Central Michigan University

In sci.space.policy Alex R. Blackwell wrote:
OM wrote:


Alex? Any comments from your friends at JPL on what's up with this?


I'm not sure what you are referring to. However, I understand there's a
2 Hz signal in some of the ISS raw data but these are being deconvolved
in the processed imagery. Typically, "banding" in raw imagery is due to
some hardware problem such as stray light (i.e., a "light leak" of the
type in the Mars Odyssey THEMIS system), though I haven't heard of that
problem with ISS.


--



Alex R. Blackwell
University of Hawaii


  #13  
Old July 3rd 04, 05:31 PM
Alex R. Blackwell
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Bruce Palmer wrote:

I remember that. ISTR somebody at or near the top of the Eurpoean space
heierarchy sent a letter to somebody in the U.S. that said "You *******s
better not back out now! We busted our asses on this thing and if you
pull out now you'll have zero credibility left with us." (One can only
imagine the reply such a letter would elicit today.)


Yes, ESA's role in "saving Cassini" from the budget axe is less
well-known but no less important than the support from other quarters.
And it also helped that American relations with Europe were, shall we
say, in a little better shape in the Clinton-Gore-Goldin era. As hard
as it is to believe now, NASA was during the mid to late 1990's, in the
process of concluding an MOA with CNES, the *French* national space
agency, for a joint series of missions culminating in Mars sample return.

--


Alex R. Blackwell
University of Hawaii

  #14  
Old July 3rd 04, 05:33 PM
Alex R. Blackwell
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DeSelby wrote:

Now what I want to know is when are the Titan images gonna show up??
The official site says the images are going to be downloaded Friday
afternoon - did they mean Saturday afternoon? Can't wait to see those,
unless they're all optical in which case they will probably be pretty
boring!


I'm not sure what you're driving at. All of the T0 imagery are on the
ground and the raw data are available online.

--


Alex R. Blackwell
University of Hawaii

  #15  
Old July 3rd 04, 05:47 PM
Hop David
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Pat Flannery wrote:

Actually, that is what the rings really look like at close range- there
is a explanation of what causes the "waves" he
http://spaceflightnow.com/cassini/040701science.html
There are also spiral rings! This is one cool looking planet.

Pat


I had always assumed gaps in Saturn's rings corresponded to orbital
periods resonant with Saturn's moons. Sort of like mini-Kirkwood gaps.

Those spiral designs boggle my mind. I can't imagine what formed them.


--
Hop David
http://clowder.net/hop/index.html

  #16  
Old July 3rd 04, 06:08 PM
Andrew Gray
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On 2004-07-03, DeSelby wrote:

Now what I want to know is when are the Titan images gonna show up??
The official site says the images are going to be downloaded Friday
afternoon - did they mean Saturday afternoon? Can't wait to see those,
unless they're all optical in which case they will probably be pretty
boring!


Non-optical images? I think you mean 'visible'... ;-)

http://saturn.jpl.nasa.gov/multimedi.../raw/index.cfm has the raw
unprocessed images. Have fun...

--
-Andrew Gray

  #17  
Old July 3rd 04, 07:41 PM
Henry Spencer
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In article ,
Hop David wrote:
I had always assumed gaps in Saturn's rings corresponded to orbital
periods resonant with Saturn's moons. Sort of like mini-Kirkwood gaps.


That was the original idea -- Cassini's Division is resonant with Mimas,
for example -- but it's been known since the Voyager flybys that the real
story must be more complicated. For example, Cassini's Division is not
really entirely empty -- it's full of faint ringlets -- and there simply
aren't enough moonlets found to account for all the fine subdivisions,
even before you get into weirdness like spiral and braided structures.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |
  #18  
Old July 4th 04, 01:23 AM
Pat Flannery
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David M. Palmer wrote:

The original poster was asking about something else: groups of scan
lines that are brighter and darker, giving the image a corrugated
appearance.


When I saw the scalloped edge of the ring, I thought it was some sort of
imaging artifact; it came as quite a surprise to me that it actually had
that appearance.

Pat

  #19  
Old July 4th 04, 02:03 AM
Pat Flannery
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DeSelby wrote:

Now what I want to know is when are the Titan images gonna show up??
The official site says the images are going to be downloaded Friday
afternoon


They're up here now:
http://saturn.jpl.nasa.gov/multimedi...browseLatest=1

- did they mean Saturday afternoon? Can't wait to see those,
unless they're all optical in which case they will probably be pretty
boring!

Actually they have some neat features visible on them, particularly
this:
http://saturn.jpl.nasa.gov/multimedi...eiImageID=6978
and this:
http://saturn.jpl.nasa.gov/multimedi...eiImageID=6986
Are the dark markings the hypothesized seas?
(The little "o" shaped thing is apparently something on the camera, and
not an actual feature on the surface.)

Pat

  #20  
Old July 4th 04, 02:32 AM
OM
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On Sat, 03 Jul 2004 20:03:23 -0500, Pat Flannery
wrote:

Are the dark markings the hypothesized seas?


....Actually, as soon as I get through the remaining 28 photo shoots I
have to sort through, clean up, and post online, I'm going to start
doing some of my own image analysis and see what comes up. I'm more
interested in the white stuff poking through, especially if it's still
there on the next pass. Alex, are your contacts saying anything about
whether this is just cloud formation, or possibly something sticking
up through the haze enough to stand out in the IR?

(The little "o" shaped thing is apparently something on the camera, and
not an actual feature on the surface.)


....It's light being refracted around a dust particle that either is
stuck to the lens or imbedded. Rest assured that for my Swiss Army
Probe core design, a brush on an armature will be standard equipment,
or at least some method to remove dust particles.

OM

--

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his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr
 




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