Rosetta PDS, Images and other products made from archived data |
Rosetta PDS, Images and other products made from archived data |
Dec 14 2015, 10:48 PM
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#1
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Member Group: Members Posts: 796 Joined: 27-February 08 From: Heart of Europe Member No.: 4057 |
As we have now access to archived OSIRIS images and data from other instruments, I think that it's good idea to start up special topic for that.
Here are few results from the newly published data: Hi-Res crosseye stereo color image of Imhotep regio at resolution 0.5 m/pix. Anaglyph version: Global color image at 2.2 m/pix: -------------------- |
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Dec 20 2015, 10:57 PM
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#2
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Member Group: Members Posts: 306 Joined: 4-October 14 Member No.: 7273 |
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Dec 21 2015, 05:43 PM
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#3
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Member Group: Members Posts: 244 Joined: 2-March 15 Member No.: 7408 |
I looked for more moonlets in Herobrine's gif, this one jumped out at me on the right edge of the image. Edit: I see it now. Good eye! I kinda felt bad about not putting a little more effort into the animation given that it was so well-received and Emily even put it up on Planetary. The flickering background is really distracting to me, and it's like that because the program I wrote to spit it out used whatever the minimum value in the data was as the output zero point, and that changes from frame to frame. The maximum used was calculated in a more complex way, but also varied from frame to frame. Doing it per-frame was a bad idea and unnecessary since all 30 frames had the same filter (Empty_VIS610) and exposure time (10.2 seconds). So, I modified it to use 0 as the minimum (or something else constant; I can't remember; I tried it many different ways) and a constant maximum. I also rotated it 180 degrees like Emily did for Planetary. It looked a lot better, but I didn't ever post the improved version because I felt like it was beating a dead horse. However, since it seems some people have been looking for floaters/moonlets, I'll post this version which is much better for that. Tiny preview below. Click for full-size (2222x2049, 63 MiB) This version is built from the improved output (so no flickering background) and this time, the entire frames are included (no 1920x1080 crop) and they are all aligned1 to the background star field so stars don't move2, making it much easier to see anything floating around. The dimensions are 2222x2049 (instead of 2048x2048) because the frame position changes over time to keep the stars stationary. Empty regions at the sides, outside the bounds of a frame have been filled in with averages of other frames that did cover it. No bounce this time. At the end, it switches briefly to a frame that shows the positions, in every frame I could detect them, of 27 floaters/moonlets that I noticed in a search of the frames, overlaid on an average of all 30 frames, aligned to stars. Here's a little crop showing what it looks like. Notice the stationary star field and the track of the object that can be seen moving. Click here for just the frame with the 27 tracks on it. Each white pixel3 marks the detected position of an object in a single frame. Some of the objects are so faint that you may not be able to see them in the animation without adjusting the frame brightness/contrast. I found them by subtracting the average of all 30 frames (aligned to the star field) from each individual frame and then stacking the resulting frames in a "lighten only" way so that any moving object brighter than the background would appear as a series of dots. I checked the original frames to verify that each apparent trail was an actual object and to find the precise pixel to assign it for each frame. 1 - To the nearest pixel. I didn't want to damage the data by allowing it to be resampled/interpolated. 2 - Stars near the left and right side of the frame actually do drift very slowly by several pixels over the course of the 30 frames. 3 - Some positions are marked by two pixels where the object center (brightest point, really) fell near the boundary between pixels. |
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Dec 21 2015, 07:21 PM
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#4
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Member Group: Members Posts: 404 Joined: 5-January 10 Member No.: 5161 |
Herobrine, that is awesome work! Amazing how many moonlets you teased out of the data. And thanks to all you other imagery wizards. Wish I had more time to participate...
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