Putting the cameras 100 yards across simulates the scale of a person with a face 100 yards between eyeballs. That's enough to make the clouds seem smaller.
How far apart do the cameras need to be to allow you to perceive depth between the stars?
Lets take as a round number 3 inches as a normal eye separation. If we put a camera on either side of the country, roughly 3000 miles apart, the scale would seem to suggest the moon could appear to be (200,000 / 1000) = 200 inches away, and the rest of the stars would seem to be out in infinity I imagine. At that scale, mars could appear as close as (36,000,000 / 1000) inches, or just 3000 feet way! That is certainly close enough for your brain to perceive depth against the stars.
Let's see, what is the moon in diameter? Roughly 2200 miles? If we follow our 1000 miles to an inch scale, the moon would appear the size of a say, a tennis ball hovering 15 feet away. Mars could be a street light as close as under a mile, and the rest of the stars would probably still be hung on their blanket out in infinity.
Here's another idea, take two images of the stars 6 months apart. The distance between your eyes would be roughly 183 million miles.
Nope, nope, that's not right. Different sets of stars would be visible at those times. You would have to go it at the spring solstice and the fall solstice, one at dawn and one at sunset. I'm not sure you can get stars to appear on camera though at those times. Perhaps if you were up high enough in elevation?
Well, I guess you could go like 3 or 4 months apart instead of six, that way you can time your shots for nighttime. 1 month after fall solstice and shoot at 8pm local standard time. Then come back 1 month before spring solstice and shoot at 4am local standard time. I figure you' could just shoot straight at Polaris for both shots, rotate one of them 180 degrees.
Hell I am doing this!