APOD: In the Shadow of Saturn (2011 Sep 04)

Comments and questions about the APOD on the main view screen.
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APOD: In the Shadow of Saturn (2011 Sep 04)

Postby APOD Robot » Sun Sep 04, 2011 4:06 am

Image In the Shadow of Saturn

Explanation: In the shadow of Saturn, unexpected wonders appear. The robotic Cassini spacecraft now orbiting Saturn drifted in giant planet's shadow for about 12 hours in 2006 and looked back toward the eclipsed Sun. Cassini saw a view unlike any other. First, the night side of Saturn is seen to be partly lit by light reflected from its own majestic ring system. Next, the rings themselves appear dark when silhouetted against Saturn, but quite bright when viewed away from Saturn, slightly scattering sunlight, in this exaggerated color image. Saturn's rings light up so much that new rings were discovered, although they are hard to see in the image. Seen in spectacular detail, however, is Saturn's E ring, the ring created by the newly discovered ice-fountains of the moon Enceladus and the outermost ring visible above. Far in the distance, at the left, just above the bright main rings, is the almost ignorable pale blue dot of Earth.

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revloren
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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby revloren » Sun Sep 04, 2011 5:12 am

This might just be APOD of the Year. Wow! And a dot of Earth to boot.
What a universe this is! :wink:

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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby stephinity » Sun Sep 04, 2011 9:36 am

Fantastic APOD! I have a question though: I dont quite understand what's going on with the light of the rings in Saturn's shadow. If the backside of Saturn is being partially lit up by light reflected off the rings, why are the inner rings curved up so much, whereas the others seem aligned (with their rings light up directly by the Sun)? Any thoughts? Thanks!

starstruck

Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby starstruck » Sun Sep 04, 2011 9:49 am

This is a wondrous image.
To Stephinity . . good point, your comment made me look again at the picture. It looks to me like it may be some sort of a band in Saturn's atmosphere; it seems to be following the curvature of the planet rather than the rings. No idea why it shows up like this though.

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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby RedFishBlueFish » Sun Sep 04, 2011 10:00 am

Perspective.

Perspective: That one thing which I think most lacking, most needed, in my country today.

Remarkable image which leads to remarkable thoughts.

“Religions are many and diverse, but reason and goodness are one.”
Elbert Hubbard (1856-1915), Philosopher

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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby neufer » Sun Sep 04, 2011 11:16 am

stephinity wrote:
Fantastic APOD! I have a question though: I dont quite understand what's going on with the light of the rings in Saturn's shadow. If the backside of Saturn is being partially lit up by light reflected off the rings, why are the inner rings curved up so much, whereas the others seem aligned (with their rings light up directly by the Sun)? Any thoughts? Thanks!

The thin black band on Saturn is the night side equator...which is virtually unlit by the thin rings.

North of the dark equator, Saturn is lit up by the bright ring structure that you see in the APOD.

South of the dark equator, Saturn is lit up by the much much brighter sunlit side of the rings;
this is what you are erroneously calling the "curved inner rings."
Last edited by neufer on Sun Sep 04, 2011 1:53 pm, edited 1 time in total.
Art Neuendorffer

Mary Gerdt

Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby Mary Gerdt » Sun Sep 04, 2011 11:45 am

I am completely amazed. Thank you.

saturn2

Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby saturn2 » Sun Sep 04, 2011 11:57 am

Saturn, Saturn, my predilect planet.
This image is beautiful, indeed.
Some moons of Saturn have ice of water.
It will can to be important in explorations in the future.

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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby orin stepanek » Sun Sep 04, 2011 12:56 pm

And that pale blue dot! Wow; Ann would love that. 8-) :D
Orin

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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby moonstruck » Sun Sep 04, 2011 3:08 pm

Wow! Simply amazing. Thanks, Cassini team.

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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby NoelC » Sun Sep 04, 2011 7:24 pm

This image alone was worth the cost of the mission.

-Noel

Torillion

Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby Torillion » Sun Sep 04, 2011 7:35 pm

Thanks, neufer, for the explanation, but I'm afraid I still don't get it. Perhaps it's because I don't know what a night side equator is and can't find a good explanation. Any chance you could explain it? I agree with revloren, this could be the APOD of the Year.

- t

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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby neufer » Sun Sep 04, 2011 8:47 pm


Torillion wrote:
Thanks, neufer, for the explanation, but I'm afraid I still don't get it. Perhaps it's because I don't know what a night side equator is and can't find a good explanation. Any chance you could explain it?

You are confusing :
    1) the full set of back-lit rings on the left & right with
    2) the lit up backside of Saturn
    as obscured by just the A & B rings.
While the two seem to have superficially similar structures they are actually quite distinct and they are clearly separated in the APOD near the outer edge of Saturn itself (as if someone had drawn a half circle in black marker around the bottom of Saturn).

On Saturn's surface all you can really see is two simple ring bands:
    1) a dark obscuration due to the B ring and
    2) a fainter obscuration due to the A ring.
Ignore those two obscuring bands and what you see on Saturn is
    1) a bright Southern Hemisphere
    (due to backlighting from the rings)
    2) a fainter Northern Hemisphere
    (due to scattering from the rings) and
    3) a thin dark equatorial line
    (that receives no light at all from the thin rings).
Art Neuendorffer

tECH hIPPY

Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby tECH hIPPY » Mon Sep 05, 2011 1:00 am

Way Beautiful. Most totally excellent image. Do you suppose Earth is a crescent or full? Is Mars up there, too? Maybe way up in the upper left corner?

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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby Ann » Mon Sep 05, 2011 1:48 am

This image testifies to the magic of reflection nebulae.

Of course this image is supremely valuable as well as beautiful, since it represents a prespective that we can never have from the Earth.

Speaking about the Earth, exactly where in the image is the pale blue dot located? I followed the link and saw a closeup of the pale blue dot, but where in the larger image can I find its position?

Ann
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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby bystander » Mon Sep 05, 2011 2:03 am


PIA08324: Pale Blue Orb

"The Earth-and-moon system is visible as a bright blue point on the right side of the image above center. Here, Cassini is looking down on the Atlantic Ocean and the western coast of north Africa. The phase angle of Earth, seen from Cassini is about 30 degrees."

Credit: NASA/JPL/SSI

APOD Robot wrote: in this exaggerated color image.

PIA08329: In Saturn's Shadow
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

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Ann
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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby Ann » Mon Sep 05, 2011 2:31 am

bystander wrote:

PIA08324: Pale Blue Orb

"The Earth-and-moon system is visible as a bright blue point on the right side of the image above center. Here, Cassini is looking down on the Atlantic Ocean and the western coast of north Africa. The phase angle of Earth, seen from Cassini is about 30 degrees."

Credit: NASA/JPL/SSI

APOD Robot wrote: in this exaggerated color image.

PIA08329: In Saturn's Shadow


The image you showed in your post is not the right side of the image above center. And the inset can't be from that image, since the inset is clearly in black and white.

By the way, I did notice that today's APOD was produced from ultraviolet, infrared and "clear" filters, which means two invisible filters and one that won't show color. There can be little doubt, however, that the Earth looks blue from space, and if possible it should be shown as such, I think.

Ann
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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby bystander » Mon Sep 05, 2011 3:10 am

Do you ever follow links? The link from APOD takes you to PIA08329, which in turn takes you to PIA08324, which is from the left side of the APOD.

Not since NASA's Voyager 1 spacecraft saw our home as a pale blue dot from beyond the orbit of Neptune has Earth been imaged in color from the outer solar system. Now, Cassini casts powerful eyes on our home planet, and captures Earth, a pale blue orb -- and a faint suggestion of our moon -- among the glories of the Saturn system.

Earth is captured here in a natural color portrait made possible by the passing of Saturn directly in front of the sun from Cassini's point of view. At the distance of Saturn's orbit, Earth is too narrowly separated from the sun for the spacecraft to safely point its cameras and other instruments toward its birthplace without protection from the sun's glare.

The Earth-and-moon system is visible as a bright blue point on the right side of the image above center. Here, Cassini is looking down on the Atlantic Ocean and the western coast of north Africa. The phase angle of Earth, seen from Cassini is about 30 degrees.

A magnified view of the image (inset) taken through the clear filter (monochrome) shows the moon as a dim protrusion to the upper left of Earth. Seen from the outer solar system through Cassini's cameras, the entire expanse of direct human experience, so far, is nothing more than a few pixels across.

But then, you probably know better.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby neufer » Mon Sep 05, 2011 3:23 am

Ann wrote:
The image you showed in your post is not the right side of the image above center. And the inset can't be from that image, since the inset is clearly in black and white.

By the way, I did notice that today's APOD was produced from ultraviolet, infrared and "clear" filters, which means two invisible filters and one that won't show color. There can be little doubt, however, that the Earth looks blue from space, and if possible it should be shown as such, I think.

The inset is from the right side (above center) of the image bystander shows.

In both the insert & the image the Earth is clearly pale blue (not black & white).

The Earth is a deeper color of blue in the enhanced color APOD image.

Cassini is looking down on the Atlantic Ocean and the western coast of north Africa;
if it had been looking down on the Pacific Ocean no doubt the Earth would have appeared bluer.
Art Neuendorffer

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Ann
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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby Ann » Mon Sep 05, 2011 5:21 am

Thanks.

Ann
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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby stephinity » Mon Sep 05, 2011 9:19 pm

neufer wrote:

Torillion wrote:
Thanks, neufer, for the explanation, but I'm afraid I still don't get it. Perhaps it's because I don't know what a night side equator is and can't find a good explanation. Any chance you could explain it?

You are confusing :
    1) the full set of back-lit rings on the left & right with
    2) the lit up backside of Saturn
    as obscured by just the A & B rings.
While the two seem to have superficially similar structures they are actually quite distinct and they are clearly separated in the APOD near the outer edge of Saturn itself (as if someone had drawn a half circle in black marker around the bottom of Saturn).

On Saturn's surface all you can really see is two simple ring bands:
    1) a dark obscuration due to the B ring and
    2) a fainter obscuration due to the A ring.
Ignore those two obscuring bands and what you see on Saturn is
    1) a bright Southern Hemisphere
    (due to backlighting from the rings)
    2) a fainter Northern Hemisphere
    (due to scattering from the rings) and
    3) a thin dark equatorial line
    (that receives no light at all from the thin rings).


Thanks neufer for the detailed explanation... it clicked in my mind and now I totally see what you mean!

Aiea

Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby Aiea » Tue Sep 06, 2011 7:18 am

This is a reprint from October 16th 2006. http://apod.nasa.gov/apod/ap061016.html

hess

Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby hess » Wed Sep 07, 2011 2:44 am

Simply Awsome!! It just happened that way? Thank you!

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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby flyir » Wed Sep 07, 2011 10:33 pm

how great thou art

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Re: APOD: In the Shadow of Saturn (2011 Sep 04)

Postby Indigo_Sunrise » Thu Sep 08, 2011 10:57 am

This one is my all time favorites!
:clap: :clap: :clap:

I have this image in a large size [18" x 36"] hanging above my desk! Beyond cool!



:saturn:
Forget the box, just get outside.


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