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Jupiter - double moon shadow transit


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Got up around 4.00 to see the double shadow transit. I used my 100mm refractor on the Portamount - 'grab and go' because I'd been out scouting for a dark site in the evening and had not set anything else up.

Things were a bit 'wobbly wobbly' until I got the focus right but then Io's shadow was clear in moments of good seeing using the 6mm Radian. It always surprises me how sharply defined the shadows appear and once seen they are so obvious.  Europa's shadow on the other side of the disc was smaller and more difficult to see but once any wobbles had settled and in good seeing it was clearly seen chasing Io's across the planet. I watched Europa itself reach the planet's limb before my warm bed beckoned.

I love the fact that you can observe these events as they evolve in 'real time' - gives a real sense of the solar system at work. 

Hoping it will be clear for the triple shadow transit in a week's time. 

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Hi Kerry,

I agree with your view on watching the event happen, it is rather special however often seen. For me, it was a satisfying end to

what had been a frustrating session, with my recently aquired  used 12" Lightbridge. The seeing in my part the world has not been great these past few weeks

so I have been unable to appreciate the benefits of the bigger mirror, but by about 2.30 things seemed to improve, and I was able to spot the transit shadow of Io

right on the planet limb, at about 2.50 am, and as you say it is surprising how they stand out. By 4 am I was beginning to feel decidedly " chilled" and so

retired, quite happily, having seen Comet Lovejoy and a handful of Galaxies as well as the majesty of Jupiter. :smiley:

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Great report. 

It always amazes me that with quite modest equipment we can view these events from our own backyards.

BTW Io transits tonight, shadow begins at 9.10pm, transit begins at 9.38pm and Europa enters the giant's shadow at 10.24pm

Good luck and clear skies.

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Cheers for that Alan. The sky is looking good so far, and I will shortly set up both scopes for a good session tonight.

I am sure that the recent weather forecasts said that the Jetstream will by now have moved south of the British Isles,

so "seeing" should be good, I certainly hope so because until I see what I feel I should be seeing through the Dob,

I will continue to fear I bought a used telescope with inferior optics.

Good luck and clear skies. :smiley:

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