Re: Distant planets

[T3D john bercovitz <bercov@xxxxxxxxxxx>]

> I cannot resolve much more at high contrast
> conditions, like Venus or Jupiter on a dark night.  If I could, I
> would notice that they are spatially distributed and not a point
> source.
[...]
> you still can't tell that Jupiter or Venus have
> phases under optimal viewing conditions.
 
Just so everyone doesn't have to run to their calculators 8-), I
find that at opposition, Jupiter subtends 1 part in 4400 and at
elongation, Venus subtends 1 part in 4150.  A minute of arc is
1 part in 3440.  So seeing phases might be tough but seeing that
the disk is a disk should be possible.  However, I think there's
a problem here.  The eye adapts for the dark and then there is a
loss of acuity.  If we had clear skies, I think I'd try a 3 mm
aperture over my eye when looking at these planets (or the moon 
for that matter) and see if my acuity goes up.
 
John B


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