I have a question about this Cassini Saturn image., This may be a remedial question, and for that I apologize. |
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I have a question about this Cassini Saturn image., This may be a remedial question, and for that I apologize. |
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#1
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![]() Newbie ![]() Group: Members Posts: 2 Joined: 3-August 22 From: In limbo Member No.: 9204 ![]() |
![]() Hello, I’m new here. This may not be a productive question, but it’s been nagging me for a while. After a life of ignorance and doubt, I have re-embraced my love for all things space-related recently. I started by looking at Cassini images. I came across this image, which looks great, but then I remembered that Saturn’s rings are only one kilometer thick. The thought occurred to me: if the rings are that thin, how in the universe are they visible from this far away? I don’t remember the distance, but it’s millions of kilometers away, so I would think they wouldn’t be visible from that distance, unless you’re seeing them at an angle. I’m sure this is a simple answer, but I’m not knowledgeable enough. Thanks for allowing me to join the forum, and thanks for taking my question. -------------------- {
insert_ illegible_signature();} //…and two hard boiled eggs. Make that three hard boiled eggs. And one duck egg. |
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#2
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![]() Senior Member ![]() ![]() ![]() ![]() Group: Members Posts: 1421 Joined: 26-July 08 Member No.: 4270 ![]() |
It is indeed viewed at an angle. You can see this when the ring goes behind the planet.
-------------------- -- Hungry4info (Sirius_Alpha)
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#3
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![]() Newbie ![]() Group: Members Posts: 2 Joined: 3-August 22 From: In limbo Member No.: 9204 ![]() |
Oh okay. I totally didn’t see that. Thanks for pointing that out! I can finally rest easy. 😄 It can now go back to being one of my favorite Cassini images.
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insert_ illegible_signature();} //…and two hard boiled eggs. Make that three hard boiled eggs. And one duck egg. |
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#4
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Member ![]() ![]() ![]() Group: Members Posts: 228 Joined: 14-January 22 Member No.: 9140 ![]() |
Additionally, a feature does not have to appear >1 pixel (in this case, in width) to be visible. Stars are visible in, say, HST photos, but are much smaller than 1 pixel, but are very bright. An object that resolves to <1 pixel will still have an effect on the brightness of pixels and so can stand out from the background as a visible feature if the contrast is great enough.
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#5
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Member ![]() ![]() ![]() Group: Members Posts: 200 Joined: 20-November 05 From: Mare Desiderii Member No.: 563 ![]() |
See also http://satobs.org/tss.html -- a 2.54mm-wide (but rather long) string apparently easily visible from hundreds of km away.
(The angle of which is a couple of orders of magnitude smaller than notionally 1km-wide rings would be seen edge-on at the distance of the above picture, 3.2 million km.) |
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