Starship Asterisk*

http://antwrp.gsfc.nasa.gov/apod/ap070306.html
This picture of Saturn is kind of surreal. I failed to spot the clouds described in the text; but the picture still ranks high on the all time APOD list in my book.
Orin

I am wondering why the body of the planet overlaps the rings in this photo. Was the spacecraft too close to get the gap?

Cathie Hutcheson wrote:I am wondering why the body of the planet overlaps the rings in this photo. Was the spacecraft too close to get the gap?

I think maybe that the photo is a mosaic pieced together may have something to do with it. Some pieces of the mosaic may have been a little too large to fit in properly; unless the rings were under the body of the planet.
Orin

orin stepanek wrote:

Cathie Hutcheson wrote:I am wondering why the body of the planet overlaps the rings in this photo. Was the spacecraft too close to get the gap?

I think maybe that the photo is a mosaic pieced together may have something to do with it. Some pieces of the mosaic may have been a little too large to fit in properly; unless the rings were under the body of the planet. :roll:
Orin

This seems to be a reasonable answer to the question. Note how the width of the shadow is smaller than Saturn's diameter. It's as if the planet's picture was pasted on top of a picture of the rings.

By the way, this APOD is dated 6th March. Maybe the moderator could change the thread title to include a date which is both correct and rationally written, either 2007/3/6 or 6/3/2007.

How comes that Saturn's rings seem to be behind Saturn both above and below the planet? (or, since we are looking at Saturn from "above": ...seem to be below Saturn, both left and right of the planet?)

Thanks Axel; Date has been corrected! My typo.
Orin

I believe that the picture is correct. The image of Saturn would be overexposed to show the ring details. This overexposure would cause the light fron the planet to overpower that of the rings where they overlap. The rings are therefore being washed out by the light from the planet. This adds to the illusion that the planet is larger than its apparent shadow as the shadow is actually crossing at the ring plane at the equater but the planet is visible below the ring plane. It appears that the viewing angle is approx 60deg above the equater adding to the ring plane overlap.

This is because the apparent brightness of the planet is washing out the apparent brightness of the rings. They actually do pass infront of the planet but Saturn is too bright in the image to allow proper viewing of the rings.

I think I spot moons, three upper right and 1 middel left. Are they moons or pixel failures?

adjevandaalen wrote:I think I spot moons, three upper right and 1 middel left. Are they moons or pixel failures?

Hi! Welcome adjevandaalen; I really don't see anything that looks like moons on my monitor. Are they within the rings?
Orin

I believe that those in the upper right are the following moons:

Name / orbit radius / size
Prometheus / 139000km / 46km orbiting just inside the "F" ring
Pandora / 142000km / 46km orbiting just outside the "F" ring
Epimetheus / 151000km / 57km larger moon outside the rings
Janus / 151000km / 89km other larger moon outside the rings

the lower right looks like it has 2 pixle problems and the one other moon that might be atlas or pan

orin stepanek wrote:Hi! Welcome adjevandaalen

Hey, a fellow Dutchman.

orin stepanek wrote:I really don't see anything that looks like moons on my monitor. Are they within the rings?
Orin

Did you click through to the full resolution image? I can see 3 to the upper right above the rings, and one inside the wide dark band to the lower right of the image. Just above that to the left is a very faint one. There's also a faint spot outside of the rings, towards the lower right of the image. I don't know if they're actually all moons though.

The outer ring appears to be twisted. It's wonderful picture.
Peter.

inertnet wrote:

orin stepanek wrote:Hi! Welcome adjevandaalen

Hey, a fellow Dutchman.

orin stepanek wrote:I really don't see anything that looks like moons on my monitor. Are they within the rings?
Orin

Did you click through to the full resolution image? I can see 3 to the upper right above the rings, and one inside the wide dark band to the lower right of the image. Just above that to the left is a very faint one. There's also a faint spot outside of the rings, towards the lower right of the image. I don't know if they're actually all moons though.

The outer ring appears to be twisted. It's wonderful picture.
Peter.

Thanks for the nudge, I went back and had a look at the bigger picture. It is indeed a wonderful thing.
IIRC the two moons either side of the outer ring are 'shepherding' that ring into line. And because one is slightly further out from Saturn, it's orbit is slightly slower and so the two moons eventually meet, and when they pass each other, they swap sides of the ring with each other and continue along each others path. Wonderful stuff isn't it?

I agree with BMAONE23

The overexposure of the planet drowns out the rings.

Stunning photo

Andy Wade wrote:IIRC the two moons either side of the outer ring are 'shepherding' that ring into line.

Yes, I noticed the dimmer one right after I posted, and remembered reading about that as well. This image is one of those gems that make me come back to APOD everyday.

http://www.nasa.gov/mission_pages/cassi ... index.html

Watch the "Ring Movie."