AlexT wrote:
Folks

Reading through various articles about the upcoming launch of the New
Horizon probe I did not manage to locate any solid information about
the amount of energy & light available from the Sun on Pluto.

I remember having read something like "about the size and brightness
of Venus as seen from earth".

If it's true I find it really remarkable that an earth based
telescope would manage to "see" Pluto...


In 2012, for example, Pluto will be 32.2 times as far from the Sun
as we are, so sunlight will be 32.2^2 = 1037 times weaker than
we see it. That means it still delivers 1.3 W/meter^2. The sun
wojld still apear quite bright; that would make it apparent
magnitude -18.5, which is still 250 times as bright as our
view of a full Moon. That's plenty of light to see your way
around or get good images (and it's not all that much less light
than Voyager 2 had to deal with at Neptune and Triton).

Bill Keel