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Jupiter, evening of 24 March 2013 - a unique view

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#1 Svezda


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Posted 25 March 2013 - 01:49 AM

I look at Jupiter often since I keep my 14.5" / 37cm Teleport set up in the garage with wheels on but everything covered up. It's easy to roll it out onto the driveway and take a quick look (but usually I let it cool for at least half an hour if at all possible and I prefer to observe for an hour or two if clouds don't interfere).

I end up seeing unexpected Jovian sights quite often such as the GRS right on the central meridian, a satellite just about to begin a transit or a shadow of a satellite suddenly appearing on the planet (rarely, I am treated to an unexpected disappearance or reappearance of a satellite due to an eclipse). It is always so interesting, but I never saw anything like what I saw last night.

In the early evening (~8:30-9:30pm) the planet was in just about the exact geometric center of an equilateral triangle formed by two very close to equal mag. stars and the satellite Ganymede. Then, even more amazingly, this large triangle had a much smaller more or less close to equilateral triangle inside it composed of the satellites Io, Europa, and Callisto. I noted that although the four Galilean satellites usually appear to me to be almost the same color and brightness, because Europa was so close to Callisto and Io, it appeared noticeably dimmer and grayer than the other two close satellites, which appeared about the same magnitude and were cream colored. I had expected Callisto to be dimmer and darker and Europa to be brighter and more cream colored.

This orientation lasted for maybe half an hour, after which the center triangle of satellites started getting longer and looked more or less like an isosceles triangle. After an hour or more, Jupiter's motion relative to the two stars was very noticeable and it moved obviously far away from the geometric center of the large equilateral triangle.

Did anyone else note this grouping of satellites and stars near Jupiter?

#2 Astrodj


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Posted 26 March 2013 - 03:56 PM

Not I, still clouded out last night. Thanks for sharing your view. Geometric alignments can be quite striking.

I should have clear enough skies tonight to check out the "only one satellite visible" phenomena. Should be interesting!

#3 nirvanix


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Posted 26 March 2013 - 05:52 PM

Didn't see that one, saw a nice one the night before though - the 4 moons formed a rectangle around Jupiter which I had not seen before. Triangles, rectangles, Jupiter's giving us a geometry lesson. Tonight should be good too.
He's the show that never ends.

#4 REC



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Posted 28 March 2013 - 08:08 AM

Observed a nice shadow transit last night about 9pm EST. Nice detail on the planet, seeing must have been pretty good.


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