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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#101
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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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Jan 25 2011, 08:22 PM
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#102
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IMG to PNG GOD Group: Moderator Posts: 2254 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
The data discussed earlier in this thread was released at the PDS Imaging Node early this month. Using this data I have now created a far more accurate DEM of Herschel than the one I mentioned earlier in the thread. The DEM is based on stereo imagery.
First a section of the DEM. It is fairly detailed but not flawless. It is slightly 'tilted', resulting in higher elevations east of Herschel than west. The DEM reveals that Herschel has a raised rim and the crater floor is deepest north and southeast of the central peak. Now I really need to find the time to learn how to correct the camera angles using ISIS (any tips? ), the result should be a significant improvement in accuracy. Then some quick and dirty test renders where data from a simple cylindrical map has been draped over the DEM. This map is a byproduct of the DEM creation process (it really is an orthophoto). First an overview of Herschel. The crater floor is obviously fairly flat and not curved: An overview of the central peak: The view from the central peak summit looking east: Looking northeast from a few km above the crater floor, the central peak is visible at right: The field of view (FOV) in all of these images is 45° except for the last one where it is 50°. They are rendered using true vertical relief in all cases. I then decided to add Saturn just to see what things look like. Two quick test renders with a 50° FOV. First one looking east from above the western rim: And looking east over the central peak: |
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