Sunday, August 21, 2011

Jupiter from Pioneer 11.

This exquisite image of Jupiter is from Pioneer 11, the last (and the closest - 760,000 km) image to show the planet's full disk before closest approach. The image, C5 in the pioneer catalog, is a combination of a red and a blue light scan with a synthesized green.  Images like this present a processing dilemma.   Pioneer got an unusually good view during approach of the south polar region during approach and an even better view of the north polar region as it left.  In my attempts to process these images, there appears to be a blue glow around the polar regions, perhaps due to a haze.  However, since I am working from scans and not digital data and the scanned prints are of varying quality (the yellowing of the individual sheets of paper was surprisingly inconsistent) and this is near the limit of what can be discerned.  Thus, figuring out if it is real is difficult.  The limitations of the medium, plus the 6-bit nature of Pioneer images, makes interpreting faint features very difficult.
While this dataset is very limited, it provides some of the best views we have of Jupiter's poles, so I intend to do more work with it in the near future.

While I'm at it, here is image C25, taken from 2.3 million kilometers.   It shows a higher phase angle than can be seen from earth.  It does not one of the polar region images, but it is a pretty picture nonetheless.

Processed image Copyright Ted Stryk.   Original prints scanned to create this image courtesy NASA/Ames.


Bjorn Jonsson said...

I suspect the more bluish color in the polar region is a real feature. When working on my Cassini and Voyager 2 cylindrical maps I 'discovered' some hints of a color change between 60 and 65 degrees north (the color gets more bluish). The color change is rather sharply defined but the change in color isn't large.

Ted Stryk said...

Thanks, Bjorn. That is helpful. This is one area of the disk where I don't have any digital scraps, so figuring things like this out without the help of other datasets is difficult.

Anonymous said...

It is interesting to note a Russian Academy of Science person to be working off the USA's attempts to beat the Soviet Union. Nice work by the way