Hi Mark,

Looks to me as if from Worthington, Ohio, you'll see
the limb of the moon running halfway through Venus. Guide's
positions for the Moon and Venus, which come from the JPL
DE ephemerides, should be good to a small fraction of an
arcsecond, much better than is really needed for this
particular case.

My guess would be that S&T and IOTA don't consider it to
be a "real" occultation unless Venus is completely, 100%
hidden by the moon. The situation you have, with 50% of
Venus hidden, doesn't count as a "real" occultation (in their
view).

Venus has an apparent diameter of about an arcminute.
You would have to have a _really_ bad computation to get this
one wrong. (Certain other occultations -- notably of stars
by asteroids -- are much more demanding: the asteroids have
apparent diameters on the order of a tenth of an arcsecond,
so even small errors will throw the path off significantly.
Even in Guide, you have to go through a few steps to get
a really good asteroid/star occultation prediction.)

-- Bill