Great Saturn Cassini video

Go out and see the Astronomy Picture of the Day for June 13th. It's an awesome video of the Saturnian system from Cassini. If all the cosmic ray hits, perspective changes (from Cassini's orbital motion), and dust donut hole moves(due to panning, filter changes, and zooms) are original to the raw images, then I salute Chris Abbas. What a great job.

Now compare that to my crappy gif animation I made of Enceladus and Dione near the rings from 5 years ago. http://dwarmstr.blogspot.com/2006/03/saturn-enceladus-and-dione-animation.html

Saturn visible behind Lutetia during flyby

Hey, this is pretty cool; I'm always a fan of planetary conjunctions.

Saturn was visible in a few of the images of Lutetia taken by Rosetta as it passed by!

Image of the day: Tethys

The saturnian satellite Tethys, imaged on October 14th, 2009. From the viewpoint of Cassini, the Sun was nearly directly behind the spacecraft when this image was taken.


Click to enlarge

Source: NASA/JPL/Space Science Institute

Image of the day: Enceladus

Enceladus' north pole.


Click to enlarge to awesome.

via Planetary Society Blog.

Very big image of Saturn

If you haven't seen this newly released image of Saturn yet, then by all means take a look.

Pretty picture of the day

From Cassini orbiting Saturn.

Click to enlarge.


Via Planetary Society Blog

Saturn's extra-weird moons

Meet the craziest of the wacky, the weird moons of Saturn's panoply: Atlas and Pan.
In the December 7th 2007 issue of Science Sébastien Charnoz, André Brahic, Peter C. Thomas, and Carolyn C. Porco argue the equatorial ridges on these moons are a result of post-formation dumping. Pan sits in the Encke Gap in the A ring. Atlas is just outside the A ring. And it makes sense, too. They are in the outer regions of the ring system, the ridges are aligned with the Saturn ring plane, and that the kinematics would allow particles to preferentially land on the equators of these moons, plus the fact that they don't rapidly rotate (to dismiss a "frozen" rapid rotator), you can easily see this is an easy case.

Indeed, if you look at the Atlas image you can see how the central sphere is a rocky body, and the equatorial ridge is smooth, as if made of dusty particles.

One question not addressed in the paper is if Iapetus' equatorial ridge is similar in origin--others have attempted to use rapid rotation to explain that one, and it doesn't sit well when other satellites in the same system have ring-based ridges.

All of these images break my brain from the multiple viewing geometries.

Probable Future APOD from Cassini

NASA/JPL/Space Science Institute -- click to enlarge
Mimas is an old and quite battered moon. You know, the one that's 'That's No Moon', right? What's neat is that it's surface is ancient: you can date how old a surface is in the solar system by measuring the crater density. Such an old icy surface has been darkened to an albedo of 0.50 (50% reflectivity). And it compares so dramatically against the next moon out, Encedalus, which has fewer craters and is the brightest surface in the solar system: an albedo of 0.99 (99% of light reflects back from it).

The Cassini spacecraft peers through the fine, smoke-sized ice particles of Saturn's F ring toward the cratered face of Mimas. The F ring's core, which contains significantly larger particles, is dense enough to completely block the light from Mimas.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Nov. 18, 2007. The view was acquired at a distance of approximately 772,000 kilometers from Mimas

This one is nice.
But this one is in color!

Via Planetary Society Blog, a Cassini image that will likely be a future Astronomy Picture of the Day.

Iapetus

Are we freaking out about Iapetus yet? The equatorial ridge is ancient -- look at that crater density.

Rhea

Emily Lakdawalla at the Planetary Society Blog has spliced together Cassini images of Rhea and done a fantastic job of creating a massive image of a crescent Rhea.

It's really big, and really awesome. This deeply cratered moon is the second largest Saturnian satellite, with a bright (but not snow white) albedo.

Animation and images of ISS and Shuttle pass in Chicago

A fine night in Chicago, the Moon near Regulus, with Saturn halfway between the Moon and Venus.



Space Shuttle Atlantis and the International Space Station passed Chicago last night. Rising in the NW, the newly brightened ISS shone orange against the Chicago light pollution, its solar panels dominating the light. In binoculars the Shuttle was visible trailing by half a degree. As they got higher, the Shuttle became visible to the naked eye and the ISS changed color into a pure white.

Check out this awesome animation of the pass:


A single image of that animation is here, with an additional airplane trail.

See them tonight as well.

Saturn, the Moon, and Ryerson

After the Ryerson Astronomical Society meeting Monday night, Steven, Katie and I went up to the dome and observed on a nice clear night.

Saturn.

The Moon

The Moon aesthetically framed.

The telescope looking at the Moon.

Steven at the controls.

Saturn

Saturn reaches opposition today. Last night was a beautifully clear and warmish Ryerson Thursday observing night. The seeing was perfect too, leaving us agog with fantastic views of Saturn and its moons. It's a little tough identifying the satellites versus the field stars since Saturn is gliding on the edge of the Beehive open cluster, but we saw Titan, Dione, Rhea, and Tethys. My ID of Titan was from its brightness (i.e., not the brightest field star, but around magnitude 8), and the last three by their similarity and close positions to Saturn.

Need to identify Saturn's moons? Use Sky and Telescope's useful javascript tool: Saturn's Moons Javascript applet. They also have an observing guide to Saturn.

Alan Friedman has a nice image taken a few days ago that shows essentially what we saw last night, although we didn't see the Encke Gap.