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Oooooooooooh! Lovely! APoD 11/1/9.
Posted: Sun Jan 11, 2009 8:14 am
by SittingDownMan
I want to *go* there!
http://antwrp.gsfc.nasa.gov/apod/astropix.html
or
http://antwrp.gsfc.nasa.gov/apod/ap090111.html if you're reading this
after 11/1/9.
Someone should print this off as a poster, with a large, red arrow pointing
to the Pale Blue Dot and the message "You are here."
Chances are, every single human being who will ever live from now until
the species goes extinct will be well within one pixel of that dot.
But I really, really want to see this view with my own eyes.
And the Martian sunset, our galaxy from above, a close binary star system
with stars of different colours...
... I need a Starship.
SDM.
![Crying or Very sad :cry:](./images/smilies/icon_cry.gif)
In Saturn's shadow (1/11/09)
Posted: Sun Jan 11, 2009 2:14 pm
by pdog134
What are the bright radial "rays" that appear outside the rings? Artifacts?
Re: In Saturn's shadow (1/11/09)
Posted: Sun Jan 11, 2009 2:32 pm
by renshaw
The large, diffuse, and dim ones going up and down on the picture? I was wondering about that, too.
Re: In Saturn's shadow (1/11/09)
Posted: Sun Jan 11, 2009 2:39 pm
by hughhyatt
Also, why is the inner edge of the inner ring that's in Saturn's shadow offset from the one that's not in shadow? Surely, we're not seeing more through light that's reflected off the rings, then off the planet and finally back through the rings than we're seeing through scattered direct sunlight. BTW, the same thing appears to be true of the outermost edge that's in Saturn's shadow as well.
Re: In Saturn's shadow (1/11/09)
Posted: Sun Jan 11, 2009 4:10 pm
by neufer
hughhyatt wrote:Also, why is the inner edge of the inner ring that's in Saturn's shadow offset from the one that's not in shadow? Surely, we're not seeing more through light that's reflected off the rings, then off the planet and finally back through the rings than we're seeing through scattered direct sunlight. BTW, the same thing appears to be true of the outermost edge that's in Saturn's shadow as well.
The backside of Saturn is illuminated by:
1) back scattered sunlight off the sunlit side of the rings and
2) side scattered sunlight off the night side of the rings.
Neither ring illumination gets to Saturn's poles which don't see the rings.
Neither ring illumination gets to Saturn's equator hardly sees the rings.
However, the ring illumination does gradually gets brighter as one moves away from the Saturn's equator into the temperate zones
particularly in the Southern Hemisphere which receives ring back scattered sunlight.
The "inner edge of the inner ring that's in Saturn's shadow " is
actually the surface of Saturn itself demonstrating the contrast between the poorly lit Northern Hemisphere and the well lit Southern Hemisphere. The two dark bands on Saturn's Southern Hemisphere are simply the thick B & A ring bands preventing us from a relatively clear view of Saturn's entire back side. These thick B & A ring bands are also dark in the space view because they are truly (multiply scattered) opaque bands. The fact that the bright non-opaque C & D bands in the space view are approximately as bright as Saturn's back lit Southern Hemisphere (as seen through the C & D bands) is simply coincidence and the two (space & Saturn views) should not be confused with each other.
Re: In Saturn's shadow (1/11/09)
Posted: Sun Jan 11, 2009 4:28 pm
by hughhyatt
A very cogent explanation, Art, and one that would probably never have occurred to me. Thanks!
Re: In Saturn's shadow (1/11/09)
Posted: Sun Jan 11, 2009 4:37 pm
by neufer
hughhyatt wrote:A very cogent explanation, Art, and one that would probably never have occurred to me. Thanks!
Check out:
http://antwrp.gsfc.nasa.gov/apod/ap071023.html
1) opaque B & A ring band shadows on the sunlit side of Saturn as well as
2) Saturn's well illuminated backlit Southern Hemisphere.
Now combine the two in your mind for today's Saturn Southern Hemisphere:
http://apod.nasa.gov/apod/ap090111.html
Pale Blue Dot (Earth)
Posted: Sun Jan 11, 2009 5:32 pm
by apodman
Brightest pixel: pale blue dot from
http://antwrp.gsfc.nasa.gov/apod/ap090111.html ...
B-R=1
(R=159 G=149 B=160)
Brightest pixel: pale blue dot from
http://antwrp.gsfc.nasa.gov/apod/image/ ... ni_big.jpg (shrunk to my screen) ...
B-R=3
(R=204 G=193 B=207)
Brightest pixel: pale blue dot from
http://antwrp.gsfc.nasa.gov/apod/image/ ... ni_big.jpg (full size) ...
B-R=3
(R=195 G=184 B=198)
Pale blue indeed. Though the "white" rings provide a slightly red "bias" to the eye, rendering the apparent hue a few notches more bluish. Imagine the paleness of the blue if the colors hadn't been "exaggerated".
---
Brightest pixel: pale blue dot from the Voyager 1 picture at
http://en.wikipedia.org/wiki/Pale_Blue_Dot
B-R=9
(R=149 G=179 B=158)
Not quite so pale, but the winner is actually green.
---
For anyone who arrived on this planet recently: R is red, G is green, and B is blue. Although ...
There is a popular belief that the
R,
G, and
B in the call letters of TV station WRGB serving New York's capital distict (Albany, Schenectady, Troy) refer to the colors of color television. Not so, according to ...
Another myth busted.
Walter
Ransom
Gail
Baker (1892-1960)
Re: In Saturn's shadow (1/11/09)
Posted: Mon Jan 12, 2009 3:27 am
by neufer
renshaw wrote:The large, diffuse, and dim ones going up and down on the picture? I was wondering about that, too.
I think it is mostly artifacts of optical system under high gain.
Perhaps, the lens got
E-Schmutz on it going through the
E ring to get good shots of
Enceladus.
Re: Oooh! Lovely! In Saturn's Shadow (2009 Jan 11)
Posted: Mon Jan 12, 2009 12:09 pm
by Indigo_Sunrise
SittingDownMan wrote:Someone should print this off as a poster....
I actually was one of several winners in an online contest, and received an 18" x 36" poster of the 'sister image' to this. It is gorgeous!!! I have it hanging right above my desk where I can look (read: gaze longingly) at it every day. 8)
P.S. You can see the two images
here.
Re: Oooh! Lovely! In Saturn's Shadow (2009 Jan 11)
Posted: Mon Jan 12, 2009 3:37 pm
by neufer
Indigo_Sunrise wrote:SittingDownMan wrote:Someone should print this off as a poster....
I actually was one of several winners in an online contest, and received an 18" x 36" poster of the 'sister image' to this. It is gorgeous!!! I have it hanging right above my desk where I can look (read: gaze longingly) at it every day. 8)
P.S. You can see the two images
here.
Reddish lens flares
<<The main rings are overexposed in a few places.
Reddish lens flares are visible in both versions of the view.
These radially extending artifacts result from light being scattered within the camera optics.>>
Re: Oooh! Lovely! In Saturn's Shadow (2009 Jan 11)
Posted: Mon Jan 12, 2009 5:33 pm
by aristarchusinexile
All I can say is, Like Wow, Man, What a Photo! And I thought (censored for youth's sake) was a trip!
Re: Oooh! Lovely! In Saturn's Shadow (2009 Jan 11)
Posted: Mon Jan 12, 2009 10:12 pm
by ta152h0
If a similar spacecraft would pull a similar stunt on Earth, would it find rings ( albeit faint ) ???
Re: Oooh! Lovely! In Saturn's Shadow (2009 Jan 11)
Posted: Tue Jan 13, 2009 1:20 pm
by dushyant
I have a question on pale blue dot.. if the camera was on the night side of the Saturn, pointed towards the Sun and the Earth visible in the camera frame.. then practically, the Sun, the Earth and the camera would be on a single line.
Which means that the camera could see only the night side of the pale blue dot (which would not be visible at all, even if its a full moon day).. Comments??
apodman wrote:Brightest pixel: pale blue dot from
http://antwrp.gsfc.nasa.gov/apod/ap090111.html ...
B-R=1
(R=159 G=149 B=160)
Brightest pixel: pale blue dot from
http://antwrp.gsfc.nasa.gov/apod/image/ ... ni_big.jpg (shrunk to my screen) ...
B-R=3
(R=204 G=193 B=207)
Brightest pixel: pale blue dot from
http://antwrp.gsfc.nasa.gov/apod/image/ ... ni_big.jpg (full size) ...
B-R=3
(R=195 G=184 B=198)
Pale blue indeed. Though the "white" rings provide a slightly red "bias" to the eye, rendering the apparent hue a few notches more bluish. Imagine the paleness of the blue if the colors hadn't been "exaggerated".
---
Brightest pixel: pale blue dot from the Voyager 1 picture at
http://en.wikipedia.org/wiki/Pale_Blue_Dot
B-R=9
(R=149 G=179 B=158)
Not quite so pale, but the winner is actually green.
---
For anyone who arrived on this planet recently: R is red, G is green, and B is blue. Although ...
There is a popular belief that the
R,
G, and
B in the call letters of TV station WRGB serving New York's capital distict (Albany, Schenectady, Troy) refer to the colors of color television. Not so, according to ...
Another myth busted.
Walter
Ransom
Gail
Baker (1892-1960)
Re: Oooh! Lovely! In Saturn's Shadow (2009 Jan 11)
Posted: Tue Jan 13, 2009 5:43 pm
by BMAONE23
dushyant wrote:I have a question on pale blue dot.. if the camera was on the night side of the Saturn, pointed towards the Sun and the Earth visible in the camera frame.. then practically, the Sun, the Earth and the camera would be on a single line.
Which means that the camera could see only the night side of the pale blue dot (which would not be visible at all, even if its a full moon day).. Comments??
apodman wrote:Brightest pixel: pale blue dot from
http://antwrp.gsfc.nasa.gov/apod/ap090111.html ...
B-R=1
(R=159 G=149 B=160)
Brightest pixel: pale blue dot from
http://antwrp.gsfc.nasa.gov/apod/image/ ... ni_big.jpg (shrunk to my screen) ...
B-R=3
(R=204 G=193 B=207)
Brightest pixel: pale blue dot from
http://antwrp.gsfc.nasa.gov/apod/image/ ... ni_big.jpg (full size) ...
B-R=3
(R=195 G=184 B=198)
Pale blue indeed. Though the "white" rings provide a slightly red "bias" to the eye, rendering the apparent hue a few notches more bluish. Imagine the paleness of the blue if the colors hadn't been "exaggerated".
---
Brightest pixel: pale blue dot from the Voyager 1 picture at
http://en.wikipedia.org/wiki/Pale_Blue_Dot
B-R=9
(R=149 G=179 B=158)
Not quite so pale, but the winner is actually green.
---
For anyone who arrived on this planet recently: R is red, G is green, and B is blue. Although ...
There is a popular belief that the
R,
G, and
B in the call letters of TV station WRGB serving New York's capital distict (Albany, Schenectady, Troy) refer to the colors of color television. Not so, according to ...
Another myth busted.
Walter
Ransom
Gail
Baker (1892-1960)
Much like we see Venus from Earth, The Earth will have phases as seen from Saturn. We could see a 1/2 Earth to likely 3/4 full before the suns brightness obscures it. And by using the Saturnian planet to block the sun's direct light, the earth, at 1/2 phase would be extended more than far enough away to be visible
Re: Oooh! Lovely! In Saturn's Shadow (2009 Jan 11)
Posted: Wed Jan 14, 2009 2:42 am
by ta152h0
Any planet, anywhere in the universe inside the orbit of the observing planet will show phases.
Re: Oooh! Lovely! In Saturn's Shadow (2009 Jan 11)
Posted: Wed Jan 14, 2009 3:14 am
by apodman
Outer planets (and their moons) show phases too, but only gibbous and full (more than 50% illuminated). Very far outer planets are almost full all of the time. Of the outer planets, the closest (Mars) shows the widest range. You can find current percent illuminated for all the planets for an observer on Earth in astronomical calendars and almanacs. Only inner planets show crescent phases (less than 50% illuminated).
2009 January 11 APOD
Posted: Sun May 10, 2009 11:13 pm
by FeO2E
wouldn't earth be much smaller? it has to be on the other side of the sun or else it would be a "new earth" view ... not a full earth as the picture depicts...
Re: 2009 January 11 APOD
Posted: Mon May 11, 2009 12:07 am
by Chris Peterson
FeO2E wrote:wouldn't earth be much smaller? it has to be on the other side of the sun or else it would be a "new earth" view ... not a full earth as the picture depicts...
The image of Earth looks bigger than it actually is, because of diffraction, JPEG artifacts, pixel position uncertainty, and who-knows-what sort of capture process, since the whole image is a mosaic made from images recorded over 12 hours.
It is impossible at that distance, with that camera, to determine the phase of the Earth (which was actually a bit over 50%). In this image, the Earth subtends an angle of 1.8 arcseconds, and the camera resolution is 12 arcseconds per pixel. So the Earth is completely unresolved.