[Physics] Physics Digest, Vol 7, Issue 3

[cj at mb-soft.com]

An additional observation.  Io and Europa are each about 2000 miles in diameter.  Say that one passed the other 2000 miles in the Z-axis.  Then no actual mutual eclipse even happens.  However, the Earth is bigger, and from certain locations on Earth, an observer could see a partial or total occultation of one by the other, even when no actual (solar) mutual eclipse had occurred.  Such detaills were part of why the math was so overwhelmingly complex.  And why an exact location on Earth was critical.  Actually, "partial" eclipses or occultations seem unimportant, as they only last a few seconds and if they result in only a minimal dimming, no big deal.

So my interest (and apparently also that of Meeus) was exclusively for total eclipses.  They only lasted a few seconds, (up to about 16 seconds max, as I recall), but they were apparently brain-jarring, as a reliable object rather suddenly disappeared, and then reappeared.

Carl Johnson
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