From: "Terrence R. Redding, Ph.D." <tredding@mac.com>

Date: October 4, 2009 6:35:52 PM MDT

To: "iotAoccultations@yahoogroups.com" <IOTAoccultations@yahoogroups.com>

Cc: macastronomer@yahoogroups.com, astro_IIDC@yahoogroups.com, osxastro@yahoogroups.com, palmbeachastro@yahoogroups.com

Subject: Europa (II) occults Io (I) 0211 UTC / 22:11 East Coast


For those planning to do this event this evening, I believe there is a problem.


At the time of the event it appears Io will be deep within the shadow of Jupiter and thus the shadow of Europa will have no effect on Io's light curve.


I try to run a simulation on every event I plan to observe using planetarium software before actually conducting the observation.  I normally do it to identify and become familiar with the star field.  For these mutual events I have primarily used the simulation to consider field of view issues associated with the mutual event and to insure stable objects to support comparative photometry will be within the field of view during an entire event.


While running the simulation for this event I noticed that Io was unobservable until 0305 UTC/ 11:05 local.  That appears to be when it comes out of Jupiter's shadow.


I plan to image this phenomena and expect to capture Io emerging from the shadow of Jupiter at about 0305 UTC.


Comments are welcome.


Terry - W6LMJ - 14.287 


Terrence R. Redding, Ph.D. 

Redding Observatory South, West Palm Beach, Florida

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