If you are outside the penumbra you see the
If you are in the penumbra you see only part of
If you are in the umbra you cannot see any of the
The fact that the moon is just barely big enough to
block out the sun results from a coincidence:
The sun is 400 times bigger than the moon,
but also almost exactly 400 times further
The orbit of the moon is elliptical.
it can block out the full sun
it isnt quite big enough,
giving an annular eclipse.
From our text:
Horizons, by Seeds