(Viewed 1,630 times)

[Centaur]

I calculate that a series of three dual shadow transits due to Galilean satellites will be seen on Jupiter this month. They all involve the shadows of #1 Io and #3 Ganymede appearing simultaneously on the planet.

Below are my predictions in CDT (UT-5) of when at least some portions of two shadows will be seen simultaneously.

2010 AUG 13 from 05:09 to 06:02 CDT
2010 AUG 20 from 07:04 to 09:21 CDT
2010 AUG 27 from 10:49 to 11:16 CDT

For Chicagoland observers the sun will rise in the middle of the August 13th event, although Jupiter will remain above the horizon throughout and should remain visible telescopically. During the August 20th event the Sun will be up throughout, and Jupiter will set shortly before the event completes. Jupiter will not be above the Chicagoland horizon for the August 27th event.

For my astronomical webpage I’ve created a couple of preview graphics of the August 13th event. I’ll switch to graphics for the later events as they approach. Click www.curtrenz.com/astronomical then go to the page for Superior Planets.

[Chicago Astronomer - Astro Joe]

Curt,

Do you think you could calculate what transit shadow was occurring at 12:00 midnight this morning, the 6th of August 2010?

I observed a transit, I think, but it was like no other one I witnessed before.

[Centaur]

Aug 6, 2010 18:22:50 GMT -6 Chicago Astronomer - Astro Joe said:

Curt,

Do you think you could calculate what transit shadow was occurring at 12:00 midnight this morning, the 6th of August 2010?

I observed a transit, I think, but it was like no other one I witnessed before.

Sure, Joe, here is my timetable for the transit of #3 Ganymede’s shadow during the night of 2010 AUG 05/06.

22:50 CDT Partial Shadow Transit Begins
23:02 CDT Total Shadow Transit Begins
01:52 CDT Total Shadow Transit Ends
02:02 CDT Partial Shadow Transit Ends

Below is my graphic. North is up. In what way was the event strange for you?

[Chicago Astronomer - Astro Joe]

Curt,

Curt is the man!

Yep...looks like direct confirmation of what I observed and imaged was indeed Ganymede.

The "dot" was not the sharp point I have witnessed before, but rather "soft" and smeared. But another astronomer with much better equipment imaged a satellite transit, and here too, it looks smeared...

(Got to gets me some better imager!)

Thanks Curt!

[Centaur]

You’re welcome, Joe. Perhaps seeing conditions were simply not good for you that night. Regarding the other guys photos, the shadow transits that night due to Io and Ganymede were not simultaneous. According to my calculations, the Io shadow transit began more than an hour after the Ganymede shadow transit had ended. He labels the images as shadows of Ganymede and Io. What actually appears is the shadow of Io and the bodies of the satellites Io and Ganymede. Since he apparently assumed there were two shadows, he may have photoshopped the image of Gamymede to make it appear darker. In the process it may have become smeared. Below is my graphic for what seems to be about the time of his rightmost photo. Again north is up, which is a 180° rotation of his images.

[Paulie pchris00]

You mean astronomers might fudge their photos?!?

[Paulie pchris00]

Hmmm... I'll be at work for the dual shadow transit next Friday morning. I haven't seen ANY shadow transits in a long time. I may have to get sick at 5 AM...

[Chicago Astronomer - Astro Joe]

"You mean astronomers might fudge their photos?!?"

Dang!....

Curt shakin' out the facts.

Sweet!

[Paulie pchris00]

Wait! I forgot I'm probably going to call off Thursday night for the Perseids, so I will get the double transit too! (As long as the "c" word isn't a problem.)

[Chicago Astronomer - Astro Joe]

Chicago Astronomer Research Site #1 for the Perseids.

Details to come.

[Centaur]

Aug 7, 2010 12:42:47 GMT -6 Chicago Astronomer - Astro Joe said:

Chicago Astronomer Research Site #1 for the Perseids.

Details to come.

Rather than change the subject of this thread, folks may want to add to my earlier Perseids thread: astronomer.proboards.com/index.cgi?board=NightSky&action=display&thread=2815

[RobbW]

Wow, Curt! Getting a little defensive about your threads, eh?!?!

P.S. That is purely sarcasm as I am merely goading you into making your 1000th post. Congrats!!!

[Paulie pchris00]

We were lucky enough to catch this Friday morning at the CARS site. Details to come soon.

[Paulie pchris00]

I have had a cheap Meade Lunar & Planetary CCD imaging system for awhile now, but have not used it much. I brought it for the Perseid peak to try to capture the dual shadow transits on Jupiter Friday morning. The results are not great, but over the course of nearly four hours I recorded the motions of the Galilean Satellites.