Ganymede Totally Occults Io - May 4

[Centaur]

The Earth passes through Jupiter’s equatorial plane approximately once every six years and recently did so on 2009 APR 16. The orbital planes of Jupiter’s four great Galilean satellites lie close to the planet’s equatorial plane. That means now we’re in a period that allows for the mutual occultation/transits and shadow occultation/transits among the satellites, i.e. satellite to satellite and not necessarily involving Jupiter.

There will be many of these mutual events from now until 2010 APR 07. I’ll provide alerts roughly a week before an event of interest to North American observers.

I predict that Jupiter’s satellite #3 Ganymede will totally occult #1 Io on 2009 MAY 04 during the pre-dawn hours for most North Americans. Below is a timetable in CDT (UT – 5). The timings are specifically for Chicagoland observers, but will vary by no more than a few seconds for those located elsewhere on Earth (in most cases less than one second).

04:35:56 CDT Partial Occultation Begins
04:39:10 CDT Total Occultation Begins
04:39:16 CDT Minimum Separation Between Centers
04:39:22 CDT Total Occultation Ends
04:42:37 CDT Partial Occultation Ends

A transit occurs when a body passes in front of one with a larger angular diameter.
An occultation occurs when a body passes in front of one with a smaller angular diameter.

I’ve created three preview graphics related to this event. They can be seen at: http://www.curtrenz.com/astronomical.html

Photos, descriptions and timing reports of this event would be welcome additions to this thread.

[hhEb09'1]

Thanks, Centaur. Anyone interested in the "dance" of the satellites, can watch Ganymede skim by Europa around midnight (CDT) that night, and slowly move to occult Io a little more than four hours later, while Callisto stays far on the other side of Jupiter.

[Centaur]

Thanks, Centaur. Anyone interested in the "dance" of the satellites, can watch Ganymede skim by Europa around midnight (CDT) that night, and slowly move to occult Io a little more than four hours later, while Callisto stays far on the other side of Jupiter.

You're welcome hh. Thanks for the added info. I did not mention that 22% partial occultation, because at that time Jupiter will be beneath the horizon for North Americans.

[hhEb09'1]

because at that time Jupiter will be beneath the horizon for North Americans.Good point! :)

All we need is an earth filter.