Anyone able to identify this moth?

It is approximately 5 1/2 or 6 inches at its widest spot, and was discovered on the outside light switch this morning. We get a lot of moths around here, but this is an awe-inspiring specimen.


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Added later:

Thanks to Ria at the Well-Trained Mind boards, I have my answer in less than twenty minutes.

This is a Polyphemus Moth (Antherae polyphemus). For more Saturniid moth information see the University of Kentucky Entomology website here.

From their website:

This light brown or fawn colored moth has a wing spread of 3.5 to 5.5 inches. Except for the eye-spots, it is less distinctly patterned than either the cecropia or promethea. There is a relatively small window-like spot near the middle of each wing, but the window of the hindwing is surrounded by a dark patch which makes it appear larger.

The polyphemus caterpillar prefers oak, hickory, elm, maple and birch but apple, beech, ash, willow, linden, rose, grape and pine are also satisfactory host plants. The caterpillar's color is light green with narrow white bars on the sides.

They are stocky and slightly thicker in the middle. Caterpillars reach their full grown length of a little less than four inches by August or September. At this time it spins an oval tough cocoon usually with a leaf of the host plant securely webbed to its surface.

The caterpillar changes to a pupa in the completed cocoon and spends the winter in this stage. The moths emerge from their cocoons and lay eggs the following June.

WOW! I can't believe we get to observe such a beautiful moth.