Voyager mosaics and images of Jupiter, A fresh look at some ancient stuff Options

[Bjorn Jonsson]

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).

[Phil Stooke]

Perhaps the most important question here is, will those corrected numbers get into the public record somewhere?

Phil

[DrShank]

all my work, especially the stereo stuff requires precise pointing, so every cassini release is spent 2 weeks or more calibrating and geometrically registering and revising the pointing vectors for all the new satellite images (altho the past year has been rather a dry spell!). what fun. but then i get to make mosaics like these.
release of the pointing info is a bit more complicated. my Galileo pointing is now public in the form of the Atlas, at least in labeled image map format. beyond that Im not sure yet . . .

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[Bjorn Jonsson]

my Galileo pointing is now public in the form of the Atlas, at least in labeled image map format.

This is great, I have always found the lack of accurate pointing info a bit strange. It means that everyone working on images with inaccuarate (or missing) pointing info must either obtain it from someone else or spend lots of time determining the correct pointing. So I suspect the same thing sometimes gets done by more than one person/team when it seems a lot of work could be saved by doing it only once.

Even the spacecraft position can be a source of problems. Today I wanted Voyager 1's position in late January 1979 but my software responded with a SPICE error so I tried the Jupiter Viewer at the PDS Rings Node but got similar results. I suspect that SPICE kernels containing Voyager 1's position aren't available for dates before 6 February but I need to check this more thorougly. I'm working on a Voyager 1 atmospheric movie by the way.