T'ain't art, but it's salvaged.

Open both the dark and light image files in Photoshop. Arrange windows
to see both shots, select the move tool, hold down Shift, and drag the
dark image into the lighter one. Using the Shift key ensures "pin
registration" of the two layers. Bring the light one (the background
layer) to the front and make sure it's selected within the Layers palette.

Select the eraser tool, set a low opacity to avoid doing too
much at a time, and begin erasing through the top layer, thereby
revealing the (darker) material in the bottom layer a little at a time.
Make multiple passes as need be. I should have darked the sky a bit
more, but hey, this is all re-do-able.

It sounds less elegant to me than sandwiching layers in Photoshop and then
using a layer mask, but well, uh, um, I don't know how to do that yet.

If you click the "Original" link to view the photo at its largest
possible size here, you'll get an idea of the actual foreground
density (it gets a bit dark in the small versions).

All praise to SilkyPix for its ability to leave color balance entirely
alone when it is changing density. Photoshop deserves a bit of credit, too.

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