Early in the morning of Aug 1, I was able to capture the shadow transit of Ganymede and the start of the transit of Ganymede itself just as the Great Red Spot (GRS) rotated into view.  I was able to capture Ganymede as a disc with at least the hint of albedo markings which was a pleasant surprise.  Jupiter is currently in what is known as its equinox season where our line of sight is edge on to the plane of the Jovian moons.  Thus, their motion across Jupiter is right along its light colored equatorial band making it easier to actually see the moons against the bright disc of Jupiter.  Ganymede is relatively dark so it shows up well in this transit.  Additionally, Ganymede is seen just above the GRS making for a nice visual image and an appreciation for the size of the GRS.  Ganymede, the largest moon in the solar system, is 3,275 miles/5,268 km in diameter.

The transit is shown as an animation.  I captured 49 3-minute videos over almost a 3 hour period with a 15 second intervals between captures.  In retrospect, that was probably overkill but it did make for a smoother animation.  There is a jump in the animation where I had to make a meridian flip so that resulted in a longer interval, hence the jump.  I also refocused and the captures after the meridian flip are much sharper than those before.  I used a ZWO Atmospheric Dispersion Corrector (ADC) and that required a bit of adjustment every 30 minutes or so resulting in differing camera orientations in each capture sequence (7 captures per sequence) which I had to address after stacking in AutoStakkert3 and sharpening in RegiStax6 (which was the only processing that I did on this version).

I used WinJuPos to de-rotate each of the 49 individual images as the result of the de-rotation is an image with north up.  Then I was able to create the animation in the PIPP software.  Each video capture was about 14,500 frames and I stacked the best 7000 frames.  As I mentioned earlier, this was probably overkill but I had initially started the imaging sequence with a different intention.  When I realized the potential of the transit, I continued with the same settings as I had initially started with.  Unfortunately, that cost me an even more visually pleasing result as Europa also began a shadow transit shortly after my imaging stopped because I ran out of disk space on my laptop.