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Emily Lakdawalla • Nov 24, 2009
Saturn's aurora, even better than before
The Cassini imaging team have posted their own processed and captioned version of the Saturn's aurora movie that I posted a preview of about six weeks ago, and it was worth the wait. It turns out that the video covers an amazing 81 hours of auroral action on Saturn's night side. This version of the video has also been annotated with lines denoting Saturn's limb and latitudes 70 and 78 degrees north latitude. The auroral action occurs at a latitude of 74 degrees north latitude and extends an amazing 1,200 kilometers above Saturn's limb, making them "the tallest known 'northern lights' in the solar system,' according to the caption released with the movie. An orange color was added to the aurora in order to help differentiate it from the star-streaked background. Other processing included the removal of cosmic ray hits and hot pixels.
Saturn's northern aurora in motion An aurora, shining high above the northern part of Saturn, moves from the night side to the day side of the planet in this movie recorded by Cassini. These observations, taken over four days, represent the first visible-light video of Saturn's auroras. They show tall auroral curtains, rapidly changing over time when viewed at the limb, or edge, of the planet's northern hemisphere. The sequence of images also reveals that Saturn's auroral curtains, the sheet-like formations of light-emitting atmospheric molecules, stretch up along Saturn's magnetic field and reach heights of more than 1,200 kilometers above the planet's limb. These are the tallest known "northern lights" in the solar system. The images were captured in black and white, but the aurora in this movie is shown in a false orange color to distinguish it from background noise in the images.Video: NASA / JPL-Caltech / SSI