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[Paulie pchris00]

Wish I would have done a better observation of this, but between rushing to set up for Comet Lovejoy when I got back to Indiana after being clouded out in the city, unknown critters making noises out in the fields at unknown distances, confirming the comet before any clouds could roll in again, and texting with the CA crew, I missed most of the partial occultation. Will try to post what pics I have later today.

[Chicago Astronomer - Astro Joe]

I would have enjoyed to image this, but Pauline said it all.

It got hazy, then the clouds rolled in during our Comet Lovejoy hunt session...and although I was quite comfortable, the C.A. crew members were getting frozen.

Pics laters...

[Paulie pchris00]

Dec 29, 2014 12:16:52 GMT -6 Chicago Astronomer - Astro Joe said:

It got hazy, then the clouds rolled in during our Comet Lovejoy hunt session...and although I was quite comfortable, the C.A. crew members were getting frozen.

Some of us had been out in the cold for five hours by the time we were clouded out...

But I wasn't really cold until I got down to Conway. I took off my cold weather gear for the drive, and without the warming effect of the Lake nearby, it felt much colder than the Chicago lakefront. My weather app said 25 degrees at 12:49 AM, but I swear it felt more like 15 degrees. Damn axial tilt...

[Paulie pchris00]

Late on Sunday, December 28, and into early Monday, December 29, I wrapped up several hours of observing in two states with a Jovian observation that, as Curt stated in the title of this thread, included Ganymede partially occulting Io.

When I left Northerly Island once the Chicago Astronomer crew was clouded out while tracking down Comet Lovejoy, I headed to Conway Observatory instead of home. For much of the drive I could see Jupiter shining brightly, so I figured the thin clouds and haze that ended our session had moved through. It was much colder down at Conway than by the Chicago Lakefront, and I had shed my cold weather clothes for the drive. I never put them back on, which made this portion of the night far less comfortable than the evening observing. It also kept me from staying out much later than I did.

While I was setting up my Dob, some haze over Lepus had moved on, so I started by finding the comet. I also tried to get some more lunar images before moonset. So by the time I turned my attention and scope to Jupiter, Ganymede was just about to start to occult Io. In fact, I could not distinguish them as separate moons. They appeared to be just a single, bright Jovian satellite.










Ganymede and Io are indistinguishable as separate moons in this image, and at the eyepiece.


After warming up for awhile inside the observatory control room, I went back out around 12:30, and documented the Galilean Moon positions before packing up and leaving.











My only goals at the start of the evening had been to observe this partial occultation, Venus, and Comet Lovejoy. Venus and the comet I observed, and if we hadn't been clouded out in the city, I think I could have done a better job documenting this partial occultation. Under the circumstances, I'm satisfied with what I was able to observe and document.

[Centaur]

Thanks, Paulie, for again providing fine photos and documentation for a mutual Galilean satellite event. These only occur in groups lasting several months before another six-year drought. It's great that you're taking advantage of the current downpour. 

[Paulie pchris00]

It's been fun. I must have bought my Dob at the end of the last period of mutual events (July 2008), or as an inexperienced observer, I hadn't noticed them. I observed Jupiter (and not much else) from July through September that year as often as I could, but without knowledge that mutual Galilean Satellite events were occurring, it would have taken some luck to see one. Now, with clear skies and frequent observing I might be able to figure out mutual events, but I appreciate the heads up you give us. I can go out at just the right time to document the event. Thank you.

[Chicago Astronomer - Astro Joe]

This is quite cool to have documented.

Wish I could have observed/imaged it as well.

Good job Paulie.

[Paulie pchris00]

Jan 8, 2015 11:05:05 GMT -6 Chicago Astronomer - Astro Joe said:

This is quite cool to have documented.

Wish I could have observed/imaged it as well.

Good job Paulie.

Thank you. I still need to post photos from the annular eclipse of Ganymede by Europa's shadow over the holiday break. That observation was interesting, but mostly inconclusive both visually and photographically.

And I have a New Year's Eve observation of the Jovian system still to post. That was interesting mostly because here in the Central Time Zone we ended 2014 with Callisto being Jupiter's only visible moon.