Io transit 25th July

[hickny]

Tonight I finally got to witness Io's transit of Jupiter in my 8" Dob. Sky and Telescope Magazine in the US maintains a site http://www.skyandtelescope.com/observing/objects/javascript/jupitee#
that lets you know when the Galilean moons transit and occultate.
Question
I am convinced that the image I saw was the Direct View image.
When I click on the Chose Your View button for Newtonian/Dobsonian the image I saw was not the same as this. Is this because I'm in the Southern Hemisphere or is there some other explanation?:shrug:

[jjjnettie]

Isn't it a blast to watch a transit!
The Australian publication,"Astronomy 2007" has an ephemeris for this as well.
Just wait till you see a double shadow transit, totally out of this world.

[erick]

Yes Peter, it's just a matter of working out the orientation as we see it from "down under". Northern hemisphere observers and southern hemisphere observers see things upside down relative to each other. (Wonder how confused observers at the equator are!) Choose a time when you can look at the "big picture" of Jupiter and the location of its four moons - a time when you have the four moons in a position that isn't confusing (confusing such as symmetrical, two on either side) - say three on one side and one on the other. Then fiddle with the software view until you see what you see in your scope or binoculars. Then make a note somewhere so that you don't forget the next time you look at the software, like I always do :P

I like sky view cafe (http://www.skyviewcafe.com/index.php ) as a simple bit of planetarium software. Once you get it running, click on the "Moons/GRS" tab at the top. "Zoom In" or "Zoom Out" to get Jupiter and its four moons nicely spaced on the display, then click "North on top" and "Celestial east on left" on/off until you get the view you are seeing through your scope or binoculars.

Eric :)

[hickny]

Eric Thanks for the feedback and the Sky Cafe web site. I'll check it out.
Jeanette Yeah! There was one about a month ago. We had a clear night but I had a family engagement at the time of the transit and so unfortunately missed it. I have bookmarked the site and check it daily that is how I knew when to look. Not sure about an "ephemeris" I'll have to delve into that one.

[iceman]

Hi Peter

I use a program called "Jupiter 2" which gives you a visual representation of the current Jupiter system, position of moons and the GRS. It's also great to go forwards and backwards in time to verify what you saw, or to plan to view the next transit.

It also lets you flip the N-S and E-W orientation to match what you see in the eyepiece. Just go out tonight and check the positions of the moons ni the eyepiece in relation to how they appear in the software, and set the orientation accordingly. Then you'll be right for future events.

[hickny]

Mike,
I have downloaded Jupiter 2. It is a really net program. It will make my observations of Jupiter in the future a lot easier.
Thanks:)