Good morning,

On Sat, 23 Aug 2003, Martha H Adams wrote:

Every time I see an image like the giant moon on the cover of the
August 2003 issue of Locus, I think it makes a wonderful image but
then I ask, but can that really happen?
[...]

For those (including yours truly) who do not read Locus regularly, here's
the image in question:
http://www.locusmag.com/2003/Issue08/cover511big.gif

The first thought that comes to mind is the photographic technique to
create a picture of a "big moon" behind a silhouetted house or grove or
what-have-you. Bearing in mind that the angular width of the moon is (for
all practical purposes) the same, regardless of your location, you travel
an appropriate distance from the house to be in the photo, such that the
house has a narrower angular width than the moon (and such that nothing
blocks your view of the house). Use a lens with a sufficiently large
magnifying power that the image will occupy most of the frame (or use a
film with a sufficiently small grain that you'll be able to blow up the
image in the darkroom to fill the photograph), and take the picture when
the moon is behind the house.

Of course, such a technique would also make the sun(?) in the Locus cover
image appear abnormally large.

Interesting conclusion we can draw from that cover image -- the star we
see must not be the primary source of light, or
1) the surface of the moon(?) would not be so visible (though this might
be dismissed as the planet having suffient albedo to reflect light onto
the moon), and
2) there wouldn't be specular reflection on the vehicles' hulls on the
viewer's side.


Take care,
cb

--
Christopher A. Bohn ____________|____________
http://www.cis.ohio-state.edu/~bohn/ ' ** ** " (o) " ** ** '
"To be prepared for war is one of the most effectual means of
preserving the peace." - George Washington, 1790