Cassini’s Grand Finale (Why I Missed Wednesday’s APotW)

Hello! You’ll noticed that I skipped Astronomy Pictures of the Week on Wednesday. That… was on purpose.

Today was Cassini’s last day alive. This morning, Cassini plunged into Saturn, sending back some amazing data, but, in the process, ending its life.

Cassini was launched on October 15th, 1997. For two decades, Cassini revealed the wonders of the greatest planet and planetary system in our solar system to us. We learned so much.

But, now, it’s over…

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Astronomy Picture of the Week – Saturn-lit Tethys

Here’s a pretty cool image

Cassini gazes across the icy rings of Saturn toward the icy moon Tethys, whose night side is illuminated by Saturnshine, or sunlight reflected by the planet.

Tethys was on the far side of Saturn with respect to Cassini here; an observer looking upward from the moon’s surface toward Cassini would see Saturn’s illuminated disk filling the sky.

Tethys was brightened by a factor of two in this image to increase its visibility. A sliver of the moon’s sunlit northern hemisphere is seen at top. A bright wedge of Saturn’s sunlit side is seen at lower left.

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Astronomy Picture of the Week – Highlighting Titan’s Hazes

Back to Cassini’s Grand Finale… today we’re highlighting Titan

NASA’s Cassini spacecraft looks toward the night side of Saturn’s moon Titan in a view that highlights the extended, hazy nature of the moon’s atmosphere. During its long mission at Saturn, Cassini has frequently observed Titan at viewing angles like this, where the atmosphere is backlit by the Sun, in order to make visible the structure of the hazes.

Titan’s high-altitude haze layer appears blue here, whereas the main atmospheric haze is orange. The difference in color could be due to particle sizes in the haze. The blue haze likely consists of smaller particles than the orange haze.

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Astronomy Picture(s and Video) of the Week: US Total Solar Eclipse, August 21, 2017

Taking a detour from Cassini’s Grand Finale to celebrate the solar eclipse we had in the US just this past Monday. I’m sad to say that, from my vantage point (Long Island, New York), it was pretty underwhelming. I wish I’d had the money and time to travel to somewhere along the path of totality and really observe it. Hopefully I’ll be able to for the next one. I’m quite positive that this isn’t my first, but it could just be that I watched clips of one when I was younger. Did the last total solar eclipse in the US happen sometime within the last 30 years?

Hm…

Anyways…

The eclipse has been called the “Great American Eclipse” which like… they know that Canada and South America have had total solar eclipses, too… right? I mean… the United States isn’t the only country in America you know… But anyways

The event’s shadow began to cover land on the¬†Oregon¬†coast as a partial eclipse at 4:06¬†p.m.¬†UTC¬†(9:06¬†a.m.¬†PDT), and its land coverage ended as a partial eclipse along the South Carolina coast at about 6:44¬†p.m. UTC (2:44¬†p.m.¬†EDT).¬†Visibility as a partial eclipse in¬†Honolulu, Hawaii¬†began with sunrise at 4:20¬†p.m. UTC (6:20¬†a.m.¬†HST) and ended by 5:25¬†p.m. UTC (7:25¬†a.m. HST).

Okay so…

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Astronomy Picture of the Week – Prometheus and the Ghostly F Ring

Cassini’s Grand Finale…

The thin sliver of Saturn’s moon Prometheus lurks near ghostly structures in Saturn’s narrow F ring in this view from NASA’s Cassini spacecraft. Many of the narrow ring’s faint and wispy features result from its gravitational interactions with Prometheus (86 kilometers, or 53 miles across).

Most of the small moon’s surface is in darkness due to the viewing geometry here. Cassini was positioned behind Saturn and Prometheus with respect to the sun, looking toward the moon’s dark side and just a bit of the moon‚Äôs sunlit northern hemisphere.

Also visible here is a distinct difference in brightness between the outermost section of Saturn’s A ring (left of center) and rest of the ring, interior to the Keeler Gap (lower left).

This view looks toward the sunlit side of the rings from about 13 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 13, 2017.

The view was acquired at a distance of approximately 680,000 miles (1.1 million kilometers) from Saturn. Image scale is 4 miles (6 kilometers) per pixel.

Click the image for the tif file…

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Astronomy Picture of the Week – Haze on the Horizon

Late on this one… by a week… I know why I’m missing these, too… real life has me extra stressed… ūüôĀ

Anyways… here’s more from Cassini’s Grand Finale…

This false-color view from NASA’s Cassini spacecraft gazes toward the rings beyond Saturn’s sunlit horizon. Along the limb (the planet’s edge) at left can be seen a thin, detached haze. This haze vanishes toward the left side of the scene.

As usual… click on the image for the tif download…

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Astronomy Picture of the Week – More Textures in the C Ring

I also realize I missed last week’s APotW. Apologies…

Continuing on with the Grand Finale

This image was taken on May 29, 2017, with the Cassini spacecraft narrow-angle camera. The image was acquired on the sunlit side of the rings from a distance of about 39,800 miles (64,100 kilometers) away from the area pictured. The image scale is 1,460 feet (445 meters) per pixel. The phase angle, or sun-ring-spacecraft angle, is 137 degrees.

(See the bottom of the post for the links to download the associated .tif images…)

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Astronomy Picture of the Week – Dawn’s Early Light

As usual until September, this is from Cassini’s Grand Finale

The light of a new day on Saturn illuminates the planet’s wavy cloud patterns and the smooth arcs of the vast rings.

The light has traveled around 80 minutes since it left the sun’s surface by the time it reaches Saturn. The illumination it provides is feeble; Earth gets 100 times the intensity since it’s roughly ten times closer to the sun. Yet compared to the deep blackness of space, everything at Saturn still shines bright in the sunlight, be it direct or reflected.

This view looks toward the sunlit side of the rings from about 10 degrees above the ring plane. The image was taken with the Cassini spacecraft wide-angle camera on Feb. 25, 2017 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 939 nanometers.

The view was obtained at a distance of approximately 762,000 miles (1.23 million kilometers) from Saturn. Image scale is 45 miles (73 kilometers) per pixel.

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Astronomy Picture of the Week – Small Wonders (Cassini’s Grand Finale)

(This is 30 minutes late because I was a couple days late with GGS.)

Still on the Grand Finale, and as I said when this started, I’ll be staying here until it’s over, because yes, I’m mourning the end of Cassini’s mission. It’s an image of three of Saturn’s smaller ring moons.

I hope you enjoy this one. As always, click on the image for the .tif download…

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