Voyager mosaics and images of Jupiter, A fresh look at some ancient stuff |
Voyager mosaics and images of Jupiter, A fresh look at some ancient stuff |
Aug 20 2010, 05:47 PM
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#201
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IMG to PNG GOD Group: Moderator Posts: 2254 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
Thanks to modern computers and software the old, 'official' Voyager Jupiter images can be reprocessed into something much better. There is also a lot of Voyager data there that was never processed into color composites and/or mosaics (or at least it has not appeared on the WWW). With proper processing the apparent image quality approaches the quality of the Cassini images but needless to say the wavelength coverage is (vastly) inferior.
I have recently been taking a close look at the high resolution Voyager 1 images, i.e. the images obtained in early March 1979. This is going to result in some new and/or reprocessed mosaics. The first one is now complete and I'm working on another one. The image below is a 12 image mosaic (12 orange + 12 violet + 12 synthetic green images). The images were obtained on March 2, 1979 at a range of 4.3 million km. The first image (C1629045.IMQ) was obtained at 05:09:23 and the last one (C1629131.IMQ) at 05:46:11. The resolution is roughly 43 km/pixel. The raw images were calibrated, reprojected to simple cylindrical projection, mosaicked and then rendered using a typical viewing geometry (there is no such thing as a "correct viewing geometry" because the images were obtained over a 37 minute period with Jupiter rotating). I then fixed the color balance. I still haven't 'standardized' how I process the Voyager color. I wasn't completely satisfied with the color I got using an approach similar to what's described in another thread but I think the color could be improved a bit. The final step was to sharpen the resulting image a bit, mainly to compensate for all of the resampling that the previous processing steps required. This image shows lots of features: The Great Red Spot and one of the three white ovals present during the Voyager flybys, smaller spots, scallopped belt/zone boundaries, gravity waves, a bright equatorial plume and the dusky south polar region. I don't think I'm bragging by saying that this is probably the best Voyager 1 Jupiter mosaic that I know of, mainly because of its size (12 images). I will be posting more Jupiter stuff in this thread in the coming days/weeks, both mosaics and interesting images (and needless to say, others are welcome to post images and mosaics as well). |
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Aug 26 2016, 11:10 PM
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#202
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IMG to PNG GOD Group: Moderator Posts: 2254 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
Here are two very high resolution Voyager 1 images of Jupiter - the resolution is ~5 km/pixel (this corresponds to a JunoCam altitude of ~9000 km). The processing is probably best described as quick and dirty and the intention was to show two very different areas at very high resolution.
One of the images shows a lot of interesting features, including obvious cloud shadows and vertical relief (and maybe I should mention in passing that I have only been able to detect cloud shadows around bright clouds - probably a normal result since they would be more difficult to detect around darker clouds). The other image is rather uniform and shows no obvious small scale features. Both of these images are contrast enhanced, especially the one that lacks obvious small scale features. Juno's closest approach occurs tomorrow and I'm looking forward to see the JunoCam images. As these images show the highest resolution JunoCam images might show lots of features or they could look relatively featureless - or we might see both 'kinds' of images (perhaps most likely). And of course we'll see color images (Voyager 1 was imaging with its clear filter only when the above images were obtained). Note: I have edited one of my recent Voyager mosaic posts - the one showing the Great Red Spot. I added a schematic context view that I forgot to include when I posted the mosaic last week. |
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Aug 27 2016, 04:06 AM
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#203
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
Bjorn, the image on the left shows detail – shadows of higher clouds onto lower clouds – that I have never seen in any Jupiter image, ever! Certainly a testament to your work, as well as a happy coincidence of the lighting and shot selection; perhaps the single-filter is a good choice as well. I suspect that the shadows are visible around the bright clouds because they are at a distinctly higher level than the clouds below them, like the tops of thunderheads on Earth, but that is just an educated guess.
I will look this image over in great detail – interesting as well as beautiful! |
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