Rev 126 - Feb 4-22, 2010 - Mimas (main target), Tethys, Iapetus, Calypso and mutual events too |
Rev 126 - Feb 4-22, 2010 - Mimas (main target), Tethys, Iapetus, Calypso and mutual events too |
Feb 4 2010, 01:35 AM
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Member Group: Members Posts: 813 Joined: 29-December 05 From: NE Oh, USA Member No.: 627 |
All
closest look at Mimas ... 30 minutes after periapsis on 02/13/10 at 17:25 UTC http://ciclops.org/view/6188/Rev126 "Thirty minutes after periapse, ISS will perform a targeted encounter with Saturn's innermost large icy satellite, Mimas. The altitude for this encounter is 9,510 kilometers (5,910 miles) the closest Cassini has ever gotten to this cratered moon. For this encounter, ISS will acquire three mosaics along with another observation where ISS will be riding along with the Composite Infrared Spectrometer (CIRS). ISS' first mosaic of Mimas, GEOLOG001, will start 30 minutes after closest approach when Cassini is 14,800 kilometers (9,200 miles) away from Mimas. GEOLOG001 is a seven-frame, multi-spectral mosaic of the region surrounding the crater Herschel. Herschel, at 130 kilometers (80 miles) across, is the largest impact basin on Mimas, so large that it caused significant amounts of stress on the lithosphere of the small moon and so distinctive that it helped give the satellite the nickname, "The Death Star Moon." These high-resolution observations of the basin will be used to estimate the age of the crater. Scientists will count the number of smaller craters on the basin floor, compared to other regions on Mimas, to set limits on how old the basin can be. The second mosaic, GEOLOG002, will also be a seven-frame, multi-spectral mosaic, this time covering most of the visible surface of Mimas, shown above left. The best resolutions for these two observations will be 87 meters (285 feet) per pixel for GEOLOG001 and 191 meters (626 feet) per pixel GEOLOG002. Next, Cassini will ride-along with a CIRS FP3 temperature map of Mimas' day side, acquiring six narrow-angle-camera images during the scan. Finally, ISS will acquire a full-frame, multispectral observation (GLOCOL001) of Mimas' anti-Saturn hemisphere from a distance of 70,000 kilometers (44,000 miles). Saturn will provide a backdrop for this observation." Glorious Craig |
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Aug 28 2011, 11:47 PM
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IMG to PNG GOD Group: Moderator Posts: 2251 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
This is an experimental Herschel animation:
http://www.youtube.com/watch?v=sfCQ7f7PMbc The DEM is an improved version of my DEM mentioned earlier in the thread. I used ISIS to improve the camera angles and instead of only using a DEM derived from stereo imagery I increased the DEM's resolution by combining two DEMs. One created using stereo imagery (for large scale features) and another one created using shape from shading (SFS; for small scale features). When using SFS care must be taken as it cannot distinguish between intensity variations caused by topography and variations caused by albedo differences. I think the SFS DEM I used is fairly accurate - after comparing the stereo DEM and some Cassini images it seems to me that most of the brightness variations on Herschel's floor are caused by topography. The final step was to 'cheat' a bit by adding lots of fictional, small craters because at this close range the surface looked too smooth without them. The field of view is 50 degrees and the distance from Mimas' center is constant (228 km) throughout the animation. When rendering this I used a uniformly white texture map, i.e. all of the surface details are coming from the DEM. |
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