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Old 18-06-2017, 07:59 PM
Tropo-Bob (Bob)
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Join Date: Sep 2013
Location: Cairns
Posts: 1,016
Quote:
Originally Posted by Tinderboxsky View Post
I will be interested to hear how you go Bob.

The ingress is occurring on the limb facing away from the sun, so it will be less well illuminated, reducing contrast. My observation was an egress on the brighter limb.

It looks like it will be clear here too, so shall hopefully give it a go.
The first indication of a shadow was seen at 20.16. From there it grew into a reverse C and finally looked circular. However, it was 20.28 before I was fully satisfied that the shadow was within Jupiter's limb. It reminded me of seeing Mercury transit over the sun and I wondered whether I was seeing a black dot affect (unlikely though). The shadow was closer to the pole than the equator so was not entering the limb at a perpendicular angle. Ganymede's large size and the glancing angle may explain why it took so long. There is also the illumination affect that Steve mentioned. Alas, the seeing was also ordinary.

Nevertheless, the weather looks good, so I may try for the exit at 10.30ish.

Last edited by Tropo-Bob; 18-06-2017 at 09:46 PM. Reason: Correct time typo for 20.18 to 20.28
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