Cassini Equinox & Solstice Mission, (nine year extension)!!.

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MeteorWayne

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Re: Cassini Equinox Mission (Cassini's two year extension).

Interesting read (as usual) from Emily Lakdawalla on TPS blog:

http://www.planetary.org/blog/article/00001909/

Moon Shadow, Moon Shadow...

It's Mimas' shadow on the rings. I'll try and post the image:




ANd upon closer inspection, the shadows of ring material!!
 
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3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

Wow Wayne,

Yes it is indeed possible to see the shadows from the ring particles. It gives the rings a real 3D effect & IIRC the first time ever this has been done.

How's this for a crescent Dione?


Andrew Brown.
 
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CalliArcale

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Re: Cassini Equinox Mission (Cassini's two year extension).

How's that?

*drools*

That's how that is! ;-) Awesome pics! Thanks!
 
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3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

Hi Calli,

I've had a go at enlargening the above crescent Dione. Looks as though it has come out quite well.


Also a crop on the left & enlargement of the image Wayne posted.

Apparently Mimas is responsible for the elevated ring particles & for the shadow in the image posted by Wayne. The smallest detail visible is approx 6.8 KM.


Andrew Brown.
 
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MeteorWayne

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Re: Cassini Equinox Mission (Cassini's two year extension).

Nice enlargement Andrew.

For those that don't take the time to read Emily's blog, the reason the shadows are so extreme is that the sun is almost perfectly aligned with the ring plane. It's less than 2 degrees from being perfectly aligned with the plane, and will be decreasing. So the next few months (Equinox is in August) should create even longer shadows. It's a great gift to have Cassini there to take these unprecedented images. It's nothing we ever could have seen before, and once Cassini is gone, will likely never see again in such detail. At least not in any of our lifetimes. As Emily suggested, the ring shadows may just be from clumps of dust. I suspect many papers will be written in the next few years analyzing these spectacular images.
 
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3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

Thanks Wayne.

It's true, it is unlikely after Cassini that we will see this again for a very long time.

You can bet that a lot of papers will be written up about this. These observations almost rank alongside geysers on Enceladus, active volcanoes on Io, ice shell potentially covering an ocean on Europa, geysers on Triton, near global coverage of Mercury for the first time, mountain belt on Iapetus, direct sampling of ice on Mars, etc.

Amazing times.

I've also had a go at enlargening the section containing the shadow cast by Mimas on the rings.


Andrew Brown.
 
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_Lucas_

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Re: Cassini Equinox Mission (Cassini's two year extension).

Hello everyone :)

Loooong time 30 yrs old lurker (can't even remember for how many years now :p), first time poster from Italy :)
---

Correct me if I'm wrong, but when looking at surface images of Titan, press-releases always refer to "bright terrain", meaning regions like Xanadu. It supposedly stays on a higher altitude compared to the darker areas (sea of dunes, so to say), but what are the theories about the composition of the aforementioned terrain? Ice or what?
----

Last, let me say Cassini is easily one of the Nasa missions I'm mostly sentimentally attached to: I watched on the web (netscape navigator, yeah!) the rocket taking off from Earth back in '97 among all those debates about plutonium, with a extraordinary 56K modem, late at night in my room; then, basically in tears and very tense when Cassini entered Saturn orbit at the beginning of July 2004 and so on, from Huygens landing, to Titan images and beyond.

What a fantastic ride :)
 
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3488

Guest
Re: Cassini Equinox Mission (Cassini's two year extension).

How's this for a weird view of Titan?

Titan eclipsed in Saturn's shadow. Titan was 664,000 KM away from Cassini.


Location of Titan just north of the Big Dipper or Plough as seen from Cassini during the eclipse.


Andrew Brown.
 
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3488

Guest
Re: Cassini Equinox Mission (Cassini's two year extension).

_Lucas_":36b1u6ks said:
Hello everyone :)

Loooong time 30 yrs old lurker (can't even remember for how many years now :p), first time poster from Italy :)
---

Correct me if I'm wrong, but when looking at surface images of Titan, press-releases always refer to "bright terrain", meaning regions like Xanadu. It supposedly stays on a higher altitude compared to the darker areas (sea of dunes, so to say), but what are the theories about the composition of the aforementioned terrain? Ice or what?
----

Last, let me say Cassini is easily one of the Nasa missions I'm mostly sentimentally attached to: I watched on the web (netscape navigator, yeah!) the rocket taking off from Earth back in '97 among all those debates about plutonium, with a extraordinary 56K modem, late at night in my room; then, basically in tears and very tense when Cassini entered Saturn orbit at the beginning of July 2004 and so on, from Huygens landing, to Titan images and beyond.

What a fantastic ride :)
Hi Lucas,

Indeed the brighter areas are deemed to be exposed ice. At Titan's -180 C or so surface temperatures, water ice is almost as hard as solid rock. The ice is strong enough to support hills, low mountains & a huge array of surface features.

Lofty ice mountains under Titan's 14% Earth surface gravity will still over time soften out & become rounded hills.

This is why also with Jupiter's Europa, Ganymede & Callisto, Titan lacks lofty mountains.

Andrew Brown.
 
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3488

Guest
Re: Cassini Equinox Mission (Cassini's two year extension).

A slight diversion from the STS 125 Atlantis mission to the Hubble Space Telescope.

On Wednesday 13th May 2009, the Cassini Spacecraft observed the shadow of the Saturn moon Enceladus pass across Mimas in a rare eclipse, during the Kronian equinoctial period. Distance to Mimas was approx 1.2 million KM.

A little montage I put together.



Andrew Brown.
 
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3488

Guest
Re: Cassini Equinox Mission (Cassini's two year extension).

Small ring moon Pan casting a shadow onto the rings, as seen by Cassini on: Sunday 24th May 2009.


My own crop & enlargement.


Andrew Brown.
 
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MeteorWayne

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Re: Cassini Equinox Mission (Cassini's two year extension).

These moon and ring shadows are a side effect of the ring plane alignment with the sun that I never anticipated.
We are blessed to have Cassini there during this time.
Thanx Andrew.
 
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3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

MeteorWayne":3hmyhp4b said:
These moon and ring shadows are a side effect of the ring plane alignment with the sun that I never anticipated.
We are blessed to have Cassini there during this time.
Thanx Andrew.
You are very, very welcome Wayne.

I am absolutely loving it. I will be keeping a close eye on these events for sure over the coming few months. At some point we must have the shadows of Rhea & Titan crossing the rings. If so they will be dramatic as they are so large.

I still think the observation of Enceladus's shadow passing acrosss Mimas is pretty cool.

Andrew Brown.
 
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3488

Guest
Re: Cassini Equinox Mission (Cassini's two year extension).

80 KM wide ice moon Pandora slicing a shadow through the rings.

Note the Saturnshine on the night side of Pandora.

Thursday 16th April 2009.



Andrew Brown.
 
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3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

Synthetic Aperture Radar image of south polar basin on Titan.

Obtained on: Monday 22nd June 2009. T57 Encounter.

Location: 76.5 South, 147 East / 213 West (dependent on you prefered measure pf longitude)
Dimensions of frame: 190 X 140 Kilometres. Basin is approx 100 KM wide.
Eroded impact basin? Cryovolcanic caldera?


Andrew Brown.
 
F

Fomalhautian

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Re: Cassini Equinox Mission (Cassini's two year extension).

The shot of the south polar basin on Titan is interesting. It almost looks like the crater here in AZ at Meteor City..... only Titans seems to have alot more erosion at work.



Titan is really difficult for me to wrap my head around. A world where the water is the rock and gas flows like water.
 
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3488

Guest
Re: Cassini Equinox Mission (Cassini's two year extension).

Very true Fomalhautian.

Titan's surface temperatures are so low that water ice is as hard as solid rock & behaves as such. Because of these low temperatures approx minus 180 C or about the same as a British Summer, Titan is able to hold on to a dense atmosphere & methane, ethane, etc are in liquid form, acting like water on Earth.

That basin is approx 100 KM wide, where as Meteor Crater is about 1.2 KM, but yes there are many similarities between them. It is difficult to know what caused the Titan Basin, it could be an impact basin or cryovolcanic, where as there is no doubt about Meteor Crater.

Hi all,

Nice view of Dione, another of one of the more interesting of Saturn's moons.

Basin on Dione.



Andrew Brown.
 
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3488

Guest
Re: Cassini Equinox Mission (Cassini's two year extension).

Some nice recent'ish' updates.

Northern crescent Titan in true colour.
Titan imaged on: Tuesday 9th June 2009.


Fenzal & Aztlan on Titan
Titan imaged on: Monday 25th May 2009.


Daphnis causes Saw Tooth shadows on the A Ring.
Imaged on: Friday 26th June 2009.


Epimetheus shadow on B Ring.
Shadow imaged on: Monday 8th June 2009.


Crescent Mimas with Saturnshine & 130 KM wide Herschel Crater highlighted.
Mimas imaged on: Wednesday 3rd June 2009.


Andrew Brown.
 
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3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

My own crop & enlargement of the small moon Daphnis causing Saw Tooth ripples & resultant shadows in the A Ring.


Andrew Brown.
 
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MeteorWayne

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Re: Cassini Equinox Mission (Cassini's two year extension).

What a glorious time to have a spcecraft in orbit around Saturn!!!!!
 
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3488

Guest
Re: Cassini Equinox Mission (Cassini's two year extension).

It certainly is Wayne.

Nest Tuesday is the actual Equinox & hopefully Cassini will devote the entire day to ring observations. In my crop above, not only are the Saw Tooth ripples visible & their resulting shadows, Daphnis & her shadow, but also a 3D effect is visible in all of the ringlets that make up the A Ring, as each ringlet casts a shadow onto the next one, & so on.

This is a very time indeed to have Cassini in orbit around Saturn. I do not think anybody really anticipated the shadows of the moons on the rings at the time of the Cassini mission inception & launch.

The science from these observations will take years to analyse.

Andrew Brown.
 
M

MeteorWayne

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Re: Cassini Equinox Mission (Cassini's two year extension).

Emily Lakdawalla of The Planetary Society is back from her maternity leave, and as you might expect for her has jumped with both feet into the Equinox, which occurs tomorrow.

http://www.planetary.org/blog/article/00002040/

I'd copy some pictures, but I never seem to get that to work, so check out her blog.

MW
 
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3488

Guest
Re: Cassini Equinox Mission (Cassini's two year extension).

The below was taken on: Friday 7th August 2009, only four days prior to the Kronian Equinox!!!!!!


My own Redshift rendition of the Sunrise at Saturn's north pole tomorrow @ the Saturn Vernal Equinox.


Andrew Brown.
 
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