Check it for other times of the year- and other years. When Romer obtained his timings, was Jupiter particularly above or below the ecliptic? If an eclipse starts very close to the end of an occultation, or vice-versa, you get just about 5.5 hours. You can't get an eclipse adjacent to a transit, they have to be separated by about 1/2 an Io orbit. Just guessing here, but the 5.5 hour figure is highly suspect of occultation and eclipse durations summed. On Dec 30, 2007 1:45 PM, Kurt Fisher <fisherka@csolutions.net> wrote:

Thanks, Chuck.

I guess "emersion" means "exiting" - the shadow or transit. Granted that the date of opposition of Jupiter probably was completely different in 1676 from July 9 in 2008, but still looking at my 2008 RASC Handbook at page 218 (August) and page 220 (November), I don't see any combination of Io events with a 5.5 hour separation. OcD-EcR is about 3.5 hours. TrI-TrE is about 2 hours.