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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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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Dec 1 2010, 07:01 PM
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IMG to PNG GOD Group: Moderator Posts: 2254 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
Exactly three months ago I posted a big Voyager 1 mosaic of the Great Red Spot (GRS):
http://www.unmannedspaceflight.com/index.p...st&p=163698 Today I'm posting a slightly improved version. The first improvement is that I'm now using a significantly improved formula for creating synthetic green. This makes the color more realistic (it was too reddish) and also more similar to the color of the Voyager 2 mosaic I posted recently (actually I used the Voyager 2 mosaic to determine the new formula). Secondly, the new version is geometrically more accurate. When working on the earlier version, during one of the processing steps a software bug somehow caused me to mess up planetocentric latitude and planetographic latitude without noticing it until recently (I'm not sure why I didn't notice it earlier). The effect was to make the resulting mosaic very similiar to the view Voyager 1 would have had from a bit higher above the equatorial plane than it really was so it wasn't particularly serious. The new mosaic, at the top an enhanced, sharpened version and then a version that should have approximately natural color and contrast: |
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