by MarkBour » Thu Feb 23, 2017 4:21 am
neufer wrote:Because it's orbital plane is slightly different Daphnis is "bobbing" in "time" by ±1.5km.
(Perhaps this is the main factor in the
vertical waves
as I originally thought).
I'm wondering about the tilt of Daphnis's orbit from the ring plane. I assume the maximum "vertical offset" you mention of 1.5 km happens at only two points of its orbit, but I don't know if there's any reason that these points would be at the apokronos and perikronos ... are they (which would give Daphnis a somewhat linear back-and-forth relative motion)? Or are they at other points of the orbit, say when Daphnis is more centrally located in the gap (which would give it a circular relative motion)?
By the way, at the right are two more easily-obtained views of the Keeler Gap.
That's our own moon, seen directly over Keeler Needle in California, which is apparently named after the same astronomer. In spite of appearances, there is no evidence that our Moon was responsible for the shaping of the peaks in this image. Anyway, the Keeler Gap is a name climbers use for the dip between Keeler Needle and the summit of Mt. Whitney, seen just to the right of the needle.
Here's a view looking down through the gap.
Hopefully, this will satisfy heehaw's desire for a close-up view?
I too, am anxious for the closest, best ring-particle picture Cassini will give us. This image today was a surprise, because it is still looking at the A-ring, while Cassini is getting very close to the F-ring in its current and next few orbits. With heehaw, I'm still on the precipice, waiting.
[quote="neufer"]Because it's orbital plane is slightly different Daphnis is "bobbing" in "time" by ±1.5km.
(Perhaps this is the main factor in the [u]vertical[/u] waves [url=http://asterisk.apod.com/viewtopic.php?f=9&t=36774&p=266383#p266307]as I originally thought[/url]).[/quote]
I'm wondering about the tilt of Daphnis's orbit from the ring plane. I assume the maximum "vertical offset" you mention of 1.5 km happens at only two points of its orbit, but I don't know if there's any reason that these points would be at the apokronos and perikronos ... are they (which would give Daphnis a somewhat linear back-and-forth relative motion)? Or are they at other points of the orbit, say when Daphnis is more centrally located in the gap (which would give it a circular relative motion)?
By the way, at the right are two more easily-obtained views of the Keeler Gap. :D [float=right][attachment=1]Capture.JPG[/attachment][/float] That's our own moon, seen directly over Keeler Needle in California, which is apparently named after the same astronomer. In spite of appearances, there is no evidence that our Moon was responsible for the shaping of the peaks in this image. Anyway, the Keeler Gap is a name climbers use for the dip between Keeler Needle and the summit of Mt. Whitney, seen just to the right of the needle.
Here's a view looking down through the gap. [float=right][attachment=0]Capture2.JPG[/attachment][/float]
Hopefully, this will satisfy heehaw's desire for a close-up view?
I too, am anxious for the closest, best ring-particle picture Cassini will give us. This image today was a surprise, because it is still looking at the A-ring, while Cassini is getting very close to the F-ring in its current and next few orbits. With heehaw, I'm still on the precipice, waiting.