#21  
Old 25-05-2017, 09:07 AM
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Tinderboxsky (Steve)
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Yes, a busy night. Thanks for your report Bob. I usually try to catch these busy sets of events but was completely clouded out.
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  #22  
Old 25-05-2017, 05:25 PM
Tropo-Bob (Bob)
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Yes, a busy night. Thanks for your report Bob. I usually try to catch these busy sets of events but was completely clouded out.
Thanks Steve,

There are a few busy nights coming up. On June 2nd, shadows from 2 Moons will be on Jupiter at the same time and there are various events on 31st May.

Tonight, Io reappears from Jupiter's shadow around 8.40ish
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  #23  
Old 25-05-2017, 08:42 PM
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I will definitely be out observing on 2 June. I am in Melbourne at the moment without any telescopes so won't see anything at the moment.
We have just picked up a new Cub camper trailer as we want to extend the range of our regular road trip holidays. So much room after being regular tenters for many years!

Last edited by Tinderboxsky; 25-05-2017 at 08:43 PM. Reason: Correction
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Old 02-06-2017, 06:43 PM
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Child, mother-in-law and I had a great view of the double shadow transit of Io and Europa just now. A bit late for the young one to watch too long but the spatial sense you get of the moons and their relative distance from Jupiter is quite something. Was very happy to see this clearly through my f9 ED100 at 150X.
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  #25  
Old 02-06-2017, 09:01 PM
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Tinderboxsky (Steve)
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Well done Ben and so envious. Had great plans to observe but foiled by heavy cloud.
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Old 02-06-2017, 10:19 PM
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Was really looking forward to tonights double shadow transit but right on cue had wall to wall cloud the entire time and now that it is over the cloud is breaking up again.
There will be double transits again, for the east coast, on the 9th & 16th, so surely one of those evenings have to be clear, please. Willing to sacrifice a scope if it will help.
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  #27  
Old 18-06-2017, 02:48 PM
Tropo-Bob (Bob)
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I was watching the shadow transit and egress this evening too. My first observation of the shadow was about 30 minutes before egress and yes it was quite close to the northern polar region which certainly shows up the 3 dimensional nature of our solar system.
I then returned about every 5 minutes to see the shadow gradually approach the limb. For the last 5 minutes I observed continuously to see the shadow kiss the limb and then gradually form a notch in the limb. The half way point was quite clear and then the notch gradually decreased and eventually disappeared as the shadow moved away. I enjoy the sense of motion in our solar system that these observations reveal.
Seeing was good and transparency poor but good enough. I was observing at 160X: VixenNA140SS with LVW5.
It all happens again tonight from around 8.20ish. Ganymede throws the most distinct shadow of all the moons on Jupiter. Steve's observation, which I have quoted has inspired me to be particularly interested in the first few minutes when the shadow touches the disc of Jupiter, before the full, round shape of the shadow has not yet formed.

Clear skies everyone!

Last edited by Tropo-Bob; 18-06-2017 at 03:08 PM.
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Old 18-06-2017, 04:13 PM
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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.
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  #29  
Old 18-06-2017, 07:59 PM
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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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  #30  
Old 18-06-2017, 09:06 PM
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Tinderboxsky (Steve)
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It sounds as though you have done well given you thought the seeing was ordinary. What scope and magnification were you using.
Down here it was a brilliantly clear night with high transparency but alas abysmal seeing. Jupiter's disk was boiling even at only 62X. Not a chance of seeing the shadow ingress.
I contented myself with some low power exploring of the hidden gems in and around Carina.
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Old 18-06-2017, 09:53 PM
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It sounds as though you have done well given you thought the seeing was ordinary. What scope and magnification were you using.
Down here it was a brilliantly clear night with high transparency but alas abysmal seeing. Jupiter's disk was boiling even at only 62X. Not a chance of seeing the shadow ingress.
I contented myself with some low power exploring of the hidden gems in and around Carina.
The reversal was also a slow affair, with the shadow touching the limb at 22.18 and finally exiting at 22.29. (Note, I amended my previous post, as I made a typo re the time)

I used my Vixen 115mm and a 7mm Delite EP (127x).

Steve, Carina certainly is a lovely area, where the more U look, the more U find!
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  #32  
Old 14-07-2017, 08:54 PM
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Jupiter has all 4 major moons on one side tonight, also extending out as per their orbits distance from the planet. (Io closest, then Europa, Ganymede and finally Callisto.)
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  #33  
Old 31-07-2017, 05:32 PM
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Ganymede's shadow will be again be on Jupiter tonight from 8.15ish.

As this is the largest and easiest-to-see shadow of any of Jupiter's moons, it is well worth a look!
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