APOD: Crescent Saturn (2020 Aug 08)

[APOD Robot]

Crescent Saturn

Explanation: From Earth, Saturn never shows a crescent phase. But when viewed from a spacecraft the majestic giant planet can show just a sunlit slice. This image of crescent Saturn in natural color was taken by the robotic Cassini spacecraft in 2007. It captures Saturn's rings from the side of the ring plane opposite the Sun -- the unilluminated side -- another vista not visible from Earth. Visible are subtle colors of cloud bands, the complex shadows of the rings on the planet, and the shadow of the planet on the rings. The moons Mimas, at 2 o'clock, and Janus 4 o'clock, can be seen as specks of light, but the real challenge is to find Pandora (8 o'clock). From Earth, Saturn's disk is nearly full now and opposite the Sun. Along with bright fellow giant planet Jupiter it rises in the early evening.

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[orin stepanek]

Beautiful; even a little eerie looking!

[Tim Martin]

With Saturn featured as today's APOD, many may be interested that the IMAX film In Saturns Rings (Featured on APOD in April -https://apod.nasa.gov/apod/ap200419.html) will be hosting a special live streaming event next month. Details for viewing may be found at https://www.insaturnsrings.com/

[WWW]

It's deja vu all over again? https://apod.nasa.gov/apod/ap071023.html

[Joe Stieber]

It's deja vu all over again? https://apod.nasa.gov/apod/ap071023.html

I wonder why the APOD folks don't clearly identify the weekend image replay as an encore presentation (no problem with that; they need a day off too). Every week we have someone seemingly surprised to find it's a recycled picture. The EPOD (Earth Science Picture of the Day) folks do a good job of this, for example, their picture today...

https://epod.usra.edu/blog/2020/08/enco ... -find.html

[Ann]

CrescentSaturn_cassini_1080.jpg


Beautiful; even a little eerie looking!

Looks otherworldly, doesn't it?

Ann

[Grizzly]

From Earth, Saturn's disk is nearly full now

From Earth, isn't Saturn always a disk?

[johnnydeep]

From Earth, Saturn's disk is nearly full now

From Earth, isn't Saturn always a disk?

I think it's always at least gibbous, but not always completely full.

[johnnydeep]

It's deja vu all over again? https://apod.nasa.gov/apod/ap071023.html

Well, the image is the same, but the text is not.

[johnnydeep]

Crescent Saturn

Explanation: From Earth, Saturn never shows a crescent phase. But when viewed from a spacecraft the majestic giant planet can show just a sunlit slice. This image of crescent Saturn in natural color was taken by the robotic Cassini spacecraft in 2007. It captures Saturn's rings from the side of the ring plane opposite the Sun -- the unilluminated side -- another vista not visible from Earth. Visible are subtle colors of cloud bands, the complex shadows of the rings on the planet, and the shadow of the planet on the rings. The moons Mimas, at 2 o'clock, and Janus 4 o'clock, can be seen as specks of light, but the real challenge is to find Pandora (8 o'clock). From Earth, Saturn's disk is nearly full now and opposite the Sun. Along with bright fellow giant planet Jupiter it rises in the early evening.

Took me quite a while to find Pandora. Had to increase the brightness of my display to the max! This image would have benefited from a mouse-over that pointed out where the moons were.

[DonB312]

Took me quite a while to find Pandora. Had to increase the brightness of my display to the max! This image would have benefited from a mouse-over that pointed out where the moons were.

For those with NVidia video cards, there is a setting that can really help get a much better image. Right-click on the Windows desktop, then click "NVIDIA Control Panel". Select "Change resolution" from the list on the left side. Now scroll down to the section titled "Apply the following settings" and find the "Output dynamic range" setting. It usually defaults to "Limited". If you change that setting to "Full" then click the Apply button it will keep the video card from clipping the dynamic range (the detail in the dark and white areas). This makes a very noticeable improvement (at least for me).

I don't know if that setting is available when using the NVidia drivers that come with Windows or if you have to have the drivers from the NVidia web site. But if you find the setting it is easy to try and if you don't like the results it is easy to switch it back to "Limited'.

Oh, and I agree that a mouseover on the image would have been nice. But it's still an awesome image.

[Boomer12k]

Always a great view... my shot of Saturn from the other week... a great object no matter the distance.

Taken with minimal exposure with my Zwo Color Planetary camera and Celestron Evolution 6", around 150 frames stacked and sharpened up in RegiStax 6.

:---[===] *

[orin stepanek]

CrescentSaturn_cassini_1080.jpg


Beautiful; even a little eerie looking!

Looks otherworldly, doesn't it?

Ann

Good description Ann! 🪐

[neufer]

Took me quite a while to find Pandora. Had to increase the brightness of my display to the max! This image would have benefited from a mouse-over that pointed out where the moons were.

For those with NVidia video cards, there is a setting that can really help get a much better image. Right-click on the Windows desktop, then click "NVIDIA Control Panel". Select "Change resolution" from the list on the left side. Now scroll down to the section titled "Apply the following settings" and find the "Output dynamic range" setting. It usually defaults to "Limited". If you change that setting to "Full" then click the Apply button it will keep the video card from clipping the dynamic range (the detail in the dark and white areas). This makes a very noticeable improvement (at least for me).

Alternatively, just look in the box.

---

<<Pandora is an inner satellite of Saturn. It was discovered in 1980 from photos taken by the Voyager 1 probe, and was provisionally designated S/1980 S 26. In late 1985 it was officially named after Pandora from Greek mythology. It is also designated Saturn XVII.

Pandora was thought to be an outer shepherd satellite of the F Ring. However, recent studies indicate that it does not play such a role, and that only Prometheus, the inner shepherd, contributes to the confinement of the narrow ring. It is more heavily cratered than nearby Prometheus, and has at least two large craters 30 kilometres in diameter. The majority of craters on Pandora are shallow as a result of being filled with debris. Ridges and grooves are also present on moon's surface.

The orbit of Pandora appears to be chaotic, as a consequence of a series of four 118:121 mean-motion resonances with Prometheus. The most appreciable changes in their orbits occur approximately every 6.2 years, when the periapsis of Pandora lines up with the apoapsis of Prometheus and the moons approach to within about 1,400 kilometres. Pandora also has a 3:2 mean-motion resonance with Mimas.

From its very low density and relatively high albedo, it seems likely that Pandora is a very porous icy body. There is much uncertainty in these values, however, so this remains to be confirmed.>>