Well I only tried to model a lunar eclipse once so I could get the image on
the 'home' page. It wasn't ideal, but it gave the impression of the Moon in
shadow so I used it.

Eclipse.pov models the Sun, Earth and Moon at any given time and date.

Solar Eclipses seem more interesting because you can recognise the places
the Moon's shadow falls on, but recreating the circumstances of a lunar
eclipse should be just a matter of finding the date and time when it
happens (what astronomers call the central eclipse, I think) and then
pointing the camera at the Moon's co-ordinates instead of the Earth's. The
Earth's shadow is much bigger than the Moon and you might see only a
completely darkened Moon. On the other hand a penumbral eclipse might not be
the spectacle you'd like it to be.

My comment about the light source not being able to see the shadows it makes
follows from the idea that a shadow is a place where a light source can't
reach. If your eye was a light source, it couldn't see the shadows it makes
because they're in places where your eye (as light source) isn't visible.

In a way, it reminds me of the signs we see on trucks here in Australia - If
you can't see my mirrors, I can't see you.

And I'm talking in general terms about a simple system with one real light
source and not about POVRay constructs like shadowless light sources.

It's very strange if the night and day sides of the Earth don't correspond
to the Sun because eclipse.pov (in spite of the complexity of the
astronomical calculations) essentially creates a scene with a light source
and two bodies. If POVRay can't render a simple scene like that, there's
something seriously wrong ;-)

The only fiction I introduced to my simple scene was the additional Sun and
Moon so that I could get a distinct umbra and penumbra. These extra
components are arranged inline with the real Sun and Moon so the shadows
they create line up too.

An area light sounds like a more realistic approach, provided it's
dimensioned properly, but the edges of the Moon's shadow will be indistinct
and
you won't be able to see the path of totality. I once found on the Internet
a short movie of a solar eclipse taken by Shuttle astronauts. The shadow
was precisely as I've just described.

It looks like I'll have to invest in some hardware which will run POVRay
once more. I have actually tried running POVRay on a 75MHz Pentium under
OpenBSD with no graphics capability. It actually generated 25x80 ASCII text
images onscreen while saving GIF files to disk. It was fascinating to watch
but only marginally faster than watching grass grow.

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