Thursday, February 26, 2009

Pillan Color Data from Galileo Orbit I27

The other day I posted a link to Ted Stryk's version of a color image acquired of Pillan and nearby features during the I27 encounter in February 2000. At right is my version.

Admittedly, it is a little rattier, but that's what I had to work with from the data set that was returned to Earth. This represents part of a frame from 27ISGLOCOL01, a planned three-color, four-frame mosaic of Io's anti-jovian and trailing hemisphere acquired a few hours after the I27 flyby. Unfortunately, there just wasn't enough time to downlink all the data that was acquired during the flyby before the G28 Ganymede flyby in May 2000. And this GLOCOL01 observation took the brunt of these data volume hits, though for a number of observations only partial frames could be returned. So at the end of the day, this contingency color mosaic was stripped down to these three partial color frames over Pillan. To make things worse, the near-infrared 756 nm filter image (used here for red) had several data cutouts, which unfortunately couldn't be filled by additional passes through the tape recorder on Galileo.

Compare this partial frame from data acquired four months earlier after the I24 flyby (October 1999) and 1.5 months earlier from the E26 orbit (January 2000). One thing that is apparent to me are the two new dark spots at Reiden Patera, near bottom center in the I27 frame above. This again shows activity at Reiden was confined to the margins of the patera, indicated that either Reiden was a large lava lake with fresh eruptions occurring where the lava crust breaks up where it interacts with the patera wall, or that Reiden's vents were limited to the fault lines that shaped the patera.

Link: I27 Images []

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