... and the sharpest view of the 'whale' on Pluto taken thus far:

True, but the discovery of fresh deposits of ammonia hydrates and water crystals on Charon, coupled with the darker north pole, suggests that it may have seen more recent 'activity' than Pluto itself.

Nonetheless, only time will tell ....

Io has a dark pole, suggesting that perhaps Charon has been subject to some sort of tidally-induced resurfacing.

Looks to me like the 'doughnut' feature was spotted in the mutual events data collected from 1954 to 1990:

I was hoping someone would do that Jason! Thanks.

Fantastic work, Dan: it almost looks for all the world like a mini-Ganymede's ended-up in orbit around Titan.

The latest image from the 27th (a merge of five at 500%), with HYDRA as the ostensible target:

Here's my contribution: I've rotated the image so that north is up, and enhanced the enlarged image (500% via smooth bicubic re-sampling) with a mixture of high-pass filters.

This is how the very same sequence was presented back in the day:

https://youtu.be/b1GDhWQbHfQ?t=5m28s

Thanks guys! I did this last year, and given I was preoccupied with another project, I gave myself a week to complete this movie, from start to finish. This explains some of the minor flaws I listed above, and there is scope for a revised version, perhaps using reprojected frames to fill the central gap.

I think the comparison with Io may even bolster the theory for ancient Charon cryovolcanism.

Io has darker poles, doesn't it? *rubs chin*

The color isn't perfect, and indeed one or two frames suffer minor alignment issues, but otherwise this movie of Saturn's spokes is best viewed in 1080p:

https://www.youtube.com/watch?v=dgbUaQGd4RE

It's as real as the original MVIC / LORRI data would suggest, nprev

This is my contribution: the four LORRI frames merged with the MVIC color from last month:

Good work, Dan. Looks a little like Methone to me, which is hardly surprising.

Great news, Alan: thank for the update!

The Piazzi dark feature, and its proximity to the nearby impact structure, reminds me of the dark pyroclastic halo on the southern rim of Mare Orientale (albeit far more diffuse):

Look at the equatorial band of scalloped clouds!

I've got it cracked (I think): the -fstretch command works only on calibrated ISS data (those with the _CALIB.IMG suffix), while the -s scaling factor only bears fruit when calibrating data inside IMG2PNG, and therefore must be used in conjunction with the radiometric correction option (-r).

What a wonderful experiment! I have nothing of any great profundity to say, except that some of your results are very reminiscent of the Voyager Mountains on Iapetus.

Thanks for the feedback Jason. I prefer to calibrate images with IMG2PNG as the scaling factor (-s) doesn't appear to work with calibrated data taken straight from the PDS. Is there a reason for that, I wonder ... ?

As a long-time user of Bjorn's marvellous little program, your post really made me sit up and take notice, Emily. For one, I assumed that the -r option was pretty much mandatory for converting calibrated Cassini PDS images. Furthermore, the use of the -fstretch command is something that I have used for Cassini SAR data, but certainly not for ISS files ... Are there any benefits to this approach over the -s scaling option, which is my preferred method of ensuring the PNGs have a consistent and decent range of brightness values.

Also, I never get 16-bit PNGs when converting with IMG2PNG: when I need a 16-bit image with a wide dynamic range, I resort to converting the data with three different scaling (-s) values, then combine them in layers (100-50-33) to produce a 16-bit TIFF file.

Here's my code, which I typically package into a clickable *.BAT file for expediency:



This allows me to produce images with a wide dynamic range, such as this:

As a minor diversion, here's a movie utilizing the raw images from the flyby:

https://www.youtube.com/watch?v=diof8JtzSac