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[Centaur]

The Galilean satellite Io will be transiting Jupiter simultaneously with its shadow and that of Europa during the morning of 2012 AUG 29. This will be the final dual shadow transit until 2012 DEC 27.

Since Jupiter is reentering our evening sky, I have resumed daily publication of my four preview graphics related to its Galilean satellites. Two will be appropriately updated to graphically illustrate upcoming shadow transits visible at night from North America. The Galilean satellite event timetable and the pictorial presentation of the satellite arrays visible throughout the night from North America will be updated daily.

The four preview graphics can be found toward the bottom of: www.CurtRenz.com/jupiter

Photos and descriptions of the upcoming dual shadow transit would be welcome additions to this thread.

[Paulie pchris00]

I was able to confirm Io's first contact at transit ingress at 4:32 AM CDST, and second contact about 4:36. Those were the only observations I was able to make. I need to sleep now, but I'll try to post pictures and write up later.

[Centaur]

Thanks for the confirmation of my timings, Paulie. After you've had a nice rest, we look forward to your follow-up.

[Paulie pchris00]

Well, Tuesday night/Wednesday morning was a work night, but it tends to be the slowest night of the week. I was able to sneak away for some scope time, but I had to pick and choose what I was going to observe. I spent about 20 minutes on a lunar session around 2 AM. For the dual shadow transits and shadow transits I had to choose what I was going to observe, since I couldn't observe every critical moment. The timing of Io's transit ingress fit best into my work schedule.




Early in the night I consulted Curt's transit event timetable to determine what I was going to observe.


When I finished my lunar session earlier in the night, I wanted a quick look at Jupiter and the Galilean Moons. Here is how they looked.







I went back out after 4 AM to capture the Io transit ingress. Io's shadow was already about halfway across Jupiter's disk. I would have guessed it to be about 55-60% across the disk. In some of my pictures, there appears to be a dark spot roughly where Io's shadow was. Could be the shadow, or it could be random noise on the sensor.












Io approaches the Jovian disk, while its shadow traverses Jupiter ahead of the moon.











I was using my 6" Dob with a 7.5mm eyepiece, and also a 2x Barlow. I went back and forth between using the Barlow and without, but as first contact neared, I ditched the Barlow lens. The seeing wasn't steady enough to justify it. I was getting better views with just the 7.5mm EP. I would have liked to have timed the contact down to the second (practice for the next ToV ), but this was a minimalist observation. All I had with me for timing was my phone, and I wasn't going to count down the seconds to the next minute. Besides, I'm not sure how accurate the time on my phone is. When I was sure the moon was tangent to the planet, I looked at my phone and saw 4:32. That was good enough for me this time.

I watched as Io crossed in front of Jupiter's eastern limb, and tried to determine when the tiny disk of the Moon was in front of Jupiter. This was much harder, especially with only 6" aperture to work with, but again, when I thought there was contact, I looked down at my phone. 4:36. Both times within at least a minute of Curt's predictions. I'd like to get more accurate timings on a Galilean transit, but obviously this wasn't a session for a high degree of accuracy. I do think I'm getting pretty good at timing the contacts, so if anybody is in need of a navigator at sea, we can negotiate my services. ;D




Io is too close to Jupiter for my camera to discern, but Europa is clearly visible. Too bad I knew I wasn't going to see its shadow transit or transit ingress.






Io was fully in transit now, and time for me to get back to work.


Looking forward to December's dual transit.

[Centaur]

Aug 31, 2012 9:23:10 GMT -6 Paulie pchris00 said:

Looking forward to December's dual transit.

Thank you so much for your fine photos, descriptions and timings, Paulie. You are a trooper.

Unfortunately, the next dual shadow transits will occur beneath the Chicagoland horizon or during our daytime on 2012 DEC 27, 2013 JAN 03, MAR 09, MAR 16, MAR 23, MAY 26, JUN 03, SEP 08, SEP 27, OCT 01, OCT 04 & OCT 08.

However, your long wait will be rewarded during the night of 2013 OCT 11-12. Shortly after Jupiter rises for Chicagoland a triple shadow transit will commence.

[Paulie pchris00]

That's good to know. We're working on next year's open house schedule at Conway, and I'm going to make sure we don't schedule anything public that night.

But on the other hand, next year isn't nearly as exciting as this year was, with partial solar and lunar eclipses (both clouded out) and the ToV. We're looking for some sort of event to feature.