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[Centaur]

A rare simultaneous transit across Jupiter by the shadows of three of its four great Galilean satellites will occur during the night of January 23-24. The next triple shadow transit won’t happen until 2032.

Bright Jupiter currently rises during the early evening for all observers. The triple shadow transit will be best viewed from the Americas.

I’ve created two preview graphics. They can be downloaded at CurtRenz.com/jupiter.html

I’ll publish on my website a detailed timetable for the triple shadow transit by midday on January 23. In the meantime, tonight’s Galilean satellite timetable appears there.

Photos and descriptions of the event would be welcome additions to this thread.

[Centaur]

Here are a couple of unusual events that I predict will occur during the triple shadow transit across Jupiter on the night of January 23-24.

23:49:42 CST (05:49:42 UT) – Callisto’s shadow eclipses 54% of Io, while both of their shadows fall on Jupiter and appear merged with each other.

00:21:00 CST (06:21:00 UT) – A fully lit Io appears totally immersed within the shadow of Callisto that falls on Jupiter. (Io will not be shadow eclipsed at that time.)

[Paulie pchris00]

Jan 21, 2015 21:29:09 GMT -6 Centaur said:

Here are a couple of unusual events that I predict will occur during the triple shadow transit across Jupiter on the night of January 23-24.

00:21:00 CST (06:21:00 UT) – A fully lit Io appears totally immersed within the shadow of Callisto that falls on Jupiter. (Io will not be shadow eclipsed at that time.)

I'm struggling to picture this. I take it that Io will be directly in front of the spot that Callisto's shadow will be falling on Jupiter?

When I checked the forecast this afternoon it was looking favorable. Still, I might try to find a virgin to sacrifice to Jupiter and the weather gods, just to be sure.

[Centaur]

Jan 21, 2015 22:16:36 GMT -6 Paulie pchris00 said:

Jan 21, 2015 21:29:09 GMT -6 Centaur said:

00:21:00 CST (06:21:00 UT) – A fully lit Io appears totally immersed within the shadow of Callisto that falls on Jupiter. (Io will not be shadow eclipsed at that time.)

I'm struggling to picture this. I take it that Io will be directly in front of the spot that Callisto's shadow will be falling on Jupiter?

Yes, Paulie. About a half hour after Io is partially eclipsed by the shadow of Callisto, Io will have already moved into full sunlight, and from our perspective Io will appear to be a shiny disk within the shadow of Callisto seen falling on Jupiter.

[Paulie pchris00]

Thank you for the clarification. I was having a hard time envisioning it without Io being eclipsed by Callisto's shadow, which I knew was incorrect.

[Centaur]

For those seeking my triple shadow transit graphics, my website will be down during the night of January 22-23 while my webhost transfers my website to a new server.

[Centaur]

My timetable for the January 23-24 triple shadow transit is now available: CurtRenz.com/jupiter.html

Please note that .html must now be added to the links to my webpages other than my home page. This is due to my webhost moving my website to a new server overnight. If you have bookmarked my webpages, you may have to alter the links.

[Chicago Astronomer - Astro Joe]

Man...it's perfectly clear now, (5:00 pm), but the forecast is calling for close to roll in by mid evening.

[Paulie pchris00]

I've had some sucker holes in the last hour, and clearly saw Callisto's shadow. Watching the weather satellite data, it looks like there will be opportunities to see all three shadows tonight, but with a rather short window of opportunity for the simultaneous triple shadow transits, seeing them all at the same time is questionable. I'm going to wait it out.

[Paulie pchris00]

Another sucker hole is opening up just in time for Io's shadow transit to begin.

[Paulie pchris00]

The sky was opening up nicely, and there is a nice break in the clouds coming again, but currently have a cloud band over Jupiter. Io's shadow was visible in transit, much smaller than Callisto's shadow. Will attempt to image the Jovian surface plus shadows in a few minutes.

Oh, and I had a mouse join me, running around outside the Conway basement. At least it hasn't run under the base of my Dob like the mouse outside Adler did last month.

[Paulie pchris00]

Becoming cloudy again, although it's more of a haze than clouds. All first magnitude or brighter stars are shining through the haze, and some second magnitude stars, but it's obscuring the surface of Jupiter, and Europa and Callisto are barely showing through telescopically. Callisto's shadow was still visible, but I could not see Io's smaller shadow. Looking at satellite images, this haze is likely to be around for awhile. Observing the triple shadow transit is now very much in doubt.

[Paulie pchris00]

What a weird night. Nearly the entire sky is clear again. About to go observe the beginning of Europa's shadow transit, and thus, the triple shadow transit.

[Paulie pchris00]

Jupiter has three shadows!!!

Interestingly, rotating into view about the same time as Europa's shadow fell on the planet, was a dark spot in Jupiter's North Equatorial Belt. This confused my observation, and I had to come in to check Curt's graphic to see where Europa's shadow was going to fall.

The haze has moved in again, and Jupiter is just barely visible at all naked eye. I think I'm going to end the observation now, and call it a success. I obtained very little photographic evidence tonight, given the short windows of opportunity for observing, but I'll try to see if I have anything worth editing and sharing.

Also, while searching for Europa's shadow, right around 12:30, when it was fully on the planet but near the limb, I heard a noise that sounded very close. I looked up, and saw something black moving across the south end of the concrete observing circle. I'm not certain, but I think for only the second time in my life I saw a live, wild skunk. I was tempted to follow it to get a closer look, but perhaps wisely opted not to. It could have been a fat cat, but wasn't very cat-like in its movement.

[Paulie pchris00]

When I first arrived at Conway Observatory just before 9:00 PM, it was a pretty calm night. An hour or so later, there was a steady breeze. While writing my previous post, I could hear the wind really pick up. Given that's it's still cloudy, it feels like the weather is about to take a turn for the worse. I feel very lucky that the weather held just long enough for me to observe this triple shadow transit. I may never see it again, but now I can add a triple shadow transit to the list of events I've observed. I hope anybody else trying to observe it had similar luck.

[Centaur]

Thanks for your fine reports on the triple shadow transit, Paulie. I'm glad you had success. Now you can rest up until the next similar event in 2032. 

That may well have been a skunk. Don't do anything that might scare one of them or you may regret it.  

Your recent photos and descriptions of the Moon and a mutual Galilean shadow eclipse are also appreciated. 

[Paulie pchris00]

Jan 24, 2015 0:54:34 GMT -6 Paulie pchris00 said:

Interestingly, rotating into view about the same time as Europa's shadow fell on the planet, was a dark spot in Jupiter's North Equatorial Belt. This confused my observation, and I had to come in to check Curt's graphic to see where Europa's shadow was going to fall.

I wonder if the dark spot I almost mistook for Europa's shadow wasn't a feature in Jupiter's NEB at all, but rather Callisto? It seems to have been in the right place at about the right time.

[Paulie pchris00]

Jan 24, 2015 0:01:43 GMT -6 Paulie pchris00 said:

Callisto's shadow was still visible, but I could not see Io's smaller shadow.

Jan 21, 2015 21:29:09 GMT -6 Centaur said:

23:49:42 CST (05:49:42 UT) – Callisto’s shadow eclipses 54% of Io, while both of their shadows fall on Jupiter and appear merged with each other.

Well, duh. Of course I didn't see Io's shadow. That was about the time the shadows appeared merged, and in the poor observing conditions, was practically impossible to tell them apart. No wonder I could see the shadow was so obvious, while Jovian cloud features were muddled.