[Tropo-Bob (Bob)]

Tonight, I attempted to estimate the length of time that Europa took to return to full brightness after it began to reappear on leaving Jupiter's shadow.

It is not an easy task to determine when the moon is back to its normal brilliance. I timed this from the first appearance of a speck of light. For the first two minutes, I could see Europa growing brighter in real time. After two minutes, I resorted to only looking at it every 30 seconds and determining if the Europa was brighter than 30 seconds ago. By this coarse measure, I estimated that it took 4minutes & 30 seconds for Europa to reach 100% illumination. I used my Iphone to time this, so looking at the bright screen also made this task more difficult.

My interest in timing this stems from the different orbits and sizes of the moons. Those moons with inner orbit should have a higher angler movement than the outer moons and thus should exit the shadow more quickly. I would expect Io to be quickest out and Callisto to be slowest. However, those moons with are somewhat larger, or smaller may slightly complicate this pattern.

Looking at future events, I may be also able to do timings of moons going into Jupiter's shadow.

I would also like to attempt to do a similar timing of the moons being occulted by Jupiter. My expectation is that the time for this should be similar to the length of time taken for the moon to reappear/disappear from shadow.

Future events that I will try and view:
June 20th: Io occulation disappearance.
June 22nd: Several events with Ganymeade.